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Austin Therapeutics A Austin
Publishing Group

Review Article

Veterinary Pharmaceutical Dosage Forms: A Technical
Ramteke KH*, Joshi SA, Dighe PA and Kharat AR
Department of Pharmaceutics, Pune University, India Abstract

*Corresponding author: Ramteke KH, Department of Animal provide us with companionship, recreation, and manual labor.
Pharmaceutics, P.E.S’s Modern College of Pharmacy (for Just like a human these animal receive medicine to keep them healthy, and
ladies) Moshi, Pune University, Maharashtra, India the reasons for producing single dose veterinary dosage forms is the same as

those in humans; to permit delivery of an active in a forms that is effective, safe,
Received: September 15, 2014; Accepted: October 08, and able to handled and administered by the end user. The primary purpose
2014; Published: October 08, 2014 of this review is to provide the basic background in the design and evaluation

of veterinary dosage forms. The basic dosage forms are describe according to
their pharmaceutical characteristic, whereas the description of advanced drug
delivery system are organized according to route of administration. In contrast
in the veterinary field, the major reasons for developing a drug into a long-acting
drug delivery system is to minimize animal handling to reduce the stress to the
animals from repeated administration and to reduce the cost of treatment in the
terms of money and time spent by the end user on drug administration.

Keywords: Product quality and efficacy; Quality control tests; Solid dosage
forms; Veterinary medication

Introduction veterinary formulations, protein veterinary formulations, bolus
veterinary formulations, etc., which are presented in tablet, bolus,

Veterinary dosage forms are drug preparations designed for powder and liquid [4]. These are widely accepted in both domestic
used in or topical application to, one or more species of domestic as well as in global regions. Featuring effective curing capability,
animal and/ or other species of veterinary interest. Although the long shelf life & fast relief, these are prescribed by veterinary doctors
majority of veterinary dosage forms contain the same drug as human for various ailments in sheep, poultry, cattle, goat and camel. Cited
dosage forms, some veterinary preparation contain drugs that below is our entire range of veterinary formulations with their brief
are not widely used in humans. Examples include benzimidazole descriptions.
anthelmintics, macrolide endectocides, salicylamilide flukicides, and
chloramphenicol derivatives [1]. Veterinary pharmacology differs Tablets and boluses
from human pharmacology both in the diversity of species interest Solid dosage forms, such as compressed tablets, are one of the
and in emphasis placed on the various classes of drug. Some types most common means of administering medications to humans.
of dosage forms are suitable for used in humans and certain animal These are less popular for animals because administration may be
species. They include parenteral solution; conventional tablets and time-consuming, hazardous, and uncertain because one cannot be
capsules; oral solution and suspensions. sure the tablet is swallowed, spit out, or dropped from the mouth after

the administrator has left or moved on to another animal. Tablets that
Animal provide us with companionship, recreation, and manual are accepted voluntarily by the animal are typically chewed, which

labor [2]. Just like a human these animal receive medicine to keep them exposes the disagreeable taste of some drugs. Thus, the advantage of
healthy, and the reasons for producing single dose veterinary dosage the dosage form may be lost. This can be overcome in some cases by
forms is the same as those in humans; to permit delivery of an active the use of odors, flavors, or sweeteners [5,6]. Tablets can be coated
in a forms that is effective, safe, and able to handled and administered to differentiate the product by color, to help mitigate offensive-
by the end user. Drugs have been compounded for veterinary tasting compounds, or to prevent dusting in the bottle. Again, same
practice for many years but, Regulations and Compliance Policy techniques used for human products are utilized.
Guidelines (CPGs) should be recognized. A CPG issued in July 2003
listed the current Food and Drug Administration (FDA) limitations Drugs are given on the basis of weight or body surface area, be it
on compounding for veterinary medicine. However, veterinarians for mammals, avian species, or humans. The amount of drug needed
and pharmacists must be aware of potential incompatibilities and for a large mammal, such as a cow, or horse, tends to be stated in mg
practices that may interfere with the drug’s stability, purity, and/or or g tablet per lb (kg) of body weight. Drugs such as sulfonamides are
potency [3]. dosed at relatively high amounts; it is not unusual to prescribe as much

as 15 g of drug for each 150 lb of body weight a 750 lb cow or horse
Veterinary science is vital to study and follow practices to protect would receive 75 g of drug. Various formulations which are available

animal production practices, herd health and monitoring the spread in tablet/bolus forms are manufactured by “Dips Vetcare Genevet Pvt.
of disease. We are one of the prominent manufacturers of veterinary Ltd.” Researched and tested formulations such as PETAZOLE-300,
formulations like pharmaceutical veterinary formulations, chewable LEAV-FIN, PETAZOLE-1500 and many others. LAMISOLE -300 is

Austin Therapeutics – Volume 1 Issue 1 – 2014 Citation: Ramteke KH, Joshi SA, Dighe PA and Kharat AR. Veterinary Pharmaceutical Dosage Forms: A
ISSN: 2472-3673 | Technical Note. Austin Therapeutics. 2014;1(1): 10.
Ramteke et al. © All rights are reserved


Ramteke KH Austin Publishing Group

Figure 1: Levamisole Hcl BP 300MG. Figure 2: Balling /Bolus Gun.

highly effective and is easily available in the market. It is frequently
prescribed against all common round worms of G.I. tract and lung
worms in poultry, cattle & sheep. Tablet of LAMISOLE -300 contains
Levamisole HCl BP 300MG (Figure 1). Dosage prescribed is 7.5mg
Levamisole / kg bwt for elimination of aforesaid infestation in cattle,
sheep & goats.

A special tablet called a “bolus” is commonly used to provide
these large dosages. A bolus is nothing more than a very large tablet,
which can range from 3 to 16 g or more. Although commonly called
“horse pills,’’ they are not used exclusively with horses. Because
of the difficulty in handling horses, which may be less docile than
cows, and the possibility of choking, the bolus form must be used Figure 3: 27g Copper & 500mg Selenium Long Acting, Slow Release, Intra-
with special care in horses. Boluses are capsule shaped or cylindrical ruminal Bolus.
because a round bolus would be unwieldy and difficult to administer release Copper and Selenium supplementation in bolus form.
or swallow. Boluses are administered by an apparatus called a balling
gun, consisting of a barrel with a plunger that can hold one or more Marketed oral controlled release pharmaceuticals tablets and
boluses. The tube is inserted into the animal’s mouth over the base of boluses are given in table 1.
the tongue, and as the animal swallows the plunger is de-pressed to Capsules
push the bolus into the gullet. The bolus is thus expelled gently into
the gullet, after which it is swallowed by reflex. Stainless steel balling/ Capsules are mainly used for dogs and cats, but there are some
bolus gun with plastic head calves, goats and sheep (Figure 2) [7]. vitamin and mineral supplement capsules formulated for cattle.

There are three main treatment areas using capsules as the dosage
Bolus formulation poses challenges because of the high drug- form: nutraceuticals, vitamins and minerals, and antimicrobials.

to-excipient ratio. Less room is left for diluent, binders, and other
adjuvant needed to overcome objectionable features of the drug or While the typical gelatin capsules used for human can be used
to facilitate bolus manufacture. In ruminant animals, such as cattle for veterinary medicine if the dogs are small (e.g. Sizes no.000, no.
or sheep, it is possible to utilize the concept of long-acting boluses, 00), there are very large veterinary capsules that range in sizes from
which stay in the gastrointestinal track for periods of much longer no. 13 (2-3g) to no. 7 (14-24g). Interestingly, Capsuline manufacture
than 12 hours (sometimes days or weeks). This is because solid DOGCapsTM and CATCapsTM, which are capsule containing beef,
objects can remain in the ruminoreticular sac, a part of the bovine chicken, or bacon flavoring in the shells to entice dogs and cats to
gastrointestinal tract, indefinitely. The density of the bolus is the consume the products [3]. Rumacin TM (Figure 4) cattle capsule is
critical factor for retention in the sac. The range of density from 1.5 to a yeast / microbial supplement fortified with 6 grams of niacin, B
8.0 is believed to be desirable for prolonged retention. This is achieved vitamins and digestive enzymes for cattle during calving, shipping,
by including excipients such as iron, clay, sodium sulfate dihydrate, and during veterinary treatment. Designed to get the rumen
and dicalcium sulfate in these formulations Weight and size influence organisms functioning and manage ketosis with research proven
retention, but not as significantly as density. In small animals it is levels of niacin.
best that oral medications are tested by the animal on its own, thus Feed additives
the special compounding with flavors and in appropriate textures Feed additives are preparations used in veterinary medicine to
discussed earlier. There are still occasions when an owner may have deliver the API(s) via the water or food given to animals. The feed
to open a pet’s mouth and administer a pill through a “piller,’’ which additive may be either a solid or liquid and sometimes is called a
is a tube with a plunger [6]. 27g Copper and 500mg Selenium Bolus premix. Feed additives are further subdivided into three types [8].
for Cows and Cattle. Long acting, Slow Release Intra-ruminal Copper
and Selenium Bolus for Routine supplementation of Cows and Cattle TYPE A medicated articles: Type A medicated articles are
(Figure 3). Use at 6 Month Intervals. It provides a long acting, slow products containing one or more animal APIs, and that are sold to

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Table 1: Marketed oral controlled release pharmaceuticals product.

Brand Name Active Ingredient(s) Therapeutic
Segment Pack Details Animal Species

Zenvet Bolus Closantel 1000mg Ectoendecto
Paraticide 4 Bolus in a blister Cattle / Buffalo / Camel /

Fentas Bolus Fenbendazole 1.5gm/3gm Endoparasiticide 1.5 gm – 4 Bolus in a blister/3 gm- Cattle / Buffalo / Camel /

1 Bolus in a blister Horse
Ecotas Sacchromysescerevisiae +Lactobacillus sporogenes+ Fortified Synbiotic Cattle / Buffalo / Sheep /

Aspergillusoryzae Combination 8 Bolus in a blister Goat / Camel
Eazypet Praziquantel 50mg +pyrantelpamoate 144mg +

fenbendazole 500mg Endoparasiticide 2 Tablets in a blister/10 Tablets in
a blister Dog / Cat

A medicated articles are added to the feeds (e.g., ground corn or oats)
during the milling process of making feeds. Liquid type A medicated
articles often are sprayed in at set rates, and solid type A medicated
articles are added slowly to aid in creating uniform distribution in the
feeds. Liquid type A medicated articles can also be mixed in with bulk
water sources at prescribed amounts.

Labeling and packaging: Type A medicated articles or type B
medicated feeds include special labeling to indicate that they should
be used in the manufacture of animal feeds or added to the drinking

Figure 4: Microbial, Yeast, Niacin capsules for adult cattle. water. The labels indicate that they are not to be fed directly to animals.
licensed feed mills or producers and are intended to be further diluted Also included is a statement indicating ‘‘Not for Human Use’’. Type
by mixing into food or water prior to consumption by the animals. A medicated articles or type B medicated feeds are packaged either
Because these preparations are not actually dosed to animals, they are in paper bags, often with polyethylene liners, for solids and in plastic
not considered dosage forms. containers for liquids. Typical sizes are 50-lb bags or several-gallon

containers. Additionally, medicated feed must be stored for several
TYPE B medicated feeds: Type B medicated feeds are products months while they are being used on daily basis to mix the final feeds.

that contain a type A medicated article, or another type B medicated Storage can be in hot, moist grain bins or sometimes in the open
feed, plus a substantial quantity of nutrients (not less than 25% of the where the sun and rain can further cause problems.
total weight). Like type A medicated articles, type B medicated feeds
are intended for mixture with food or water and additional nutrients, “Vetbiolyte Supplement” (Figure 5), this range of feed supplement
are not to be fed directly to the animals, and are not considered contains Sodium chloride, Calcium lactate, Magnesium sulphate,
dosage forms. Calcium gluconate, Potassium chloride, Sodium Citrate, Sodium

bicarbonate, Ascorbic acid, Dextrose monohydrate and Carriers.
TYPE C medicated feeds: Type C medicated feeds are made Available in packed size of 250 gm, 500 gm and 1 Kg pack size.

from type A medicated articles or type B medicated feeds and are
prepared at concentrations of the API appropriate for administration 1. Provides energy and supportive therapy for chicks
to animals by mixing in food or water. Administration of type C immediately after arrival at farm.
medicated feeds can be accomplished by blending directly into the 2. For energy and supportive therapy during diseases
feed; top-dressing the preparation onto the animal’s normal daily like Nephritis, Nephrosis, Perosis, salmonellosis,
rations; or heating, steaming, and extruding into pellets that are Salmonellosis, E. coli and Coccidiosis.
mixed or top-dressed onto the animal’s food. Another form of type C
medicated feeds is compressed or molded blocks from which animals 3. In diarrhea and dysentery.
receive the API or nutrients via licking the block. 4. To maintain correct osmotic pressure and precise acid-

Preparation: Type A medicated articles that are liquids are base equilibrium.
produced by mixing the API(s) with a suitable solvent (e.g., water
or propylene glycol). The API(s) is usually dissolved to produce a
solution, but suspension products also could be produced. Type A
medicated articles that are solids are produced by blending the API
with excipients to provide a uniform dosage form when mixed with
the animal’s feed. Often the API is first mixed with an excipient
(e.g., starch or sodium alumino silicate) that has a similar particle
size and can help distribute the API uniformly throughout the final
drug product. This pre-blend is then mixed with bulking excipients
(e.g., calcium carbonate or soybean hulls). Mineral oil may be added
to aid uniform distribution, to prevent particle segregation during
shipping, and to minimize formation of airborne API particles during
production of type B or C medicated feeds. Type B or C medicated
feeds are produced at licensed feed mills or by farm producers. Type Figure 5: Feed Supplements: VETBIOLYTE.

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Factors that need to be considered in formulating premixes and through the drinking water. The medications are formulated as:
the choice of carrier are [7]: (a) Dry powders for reconstitution into liquid concentrates to be

1. Drug concentration in the premix. added to the drinking water or to be added directly to the drinking
2. Drug concentration in the final feed: if a drug premix is water or,

added to a feed so that the drug level is less than 150 ppm, (b) Concentrated solutions, which are dispensed directly in
a carrier is needed to insure adequate dilution. drinking water or injected into the drinking water through medication

3. Moisture content of drug and carrier: if the drug is proportioners incorporated into watering lines.
moisture sensitive or the carrier is subject to breakdown The advantage of medicating through drinking water versus feed
or spoilage from moisture levels in the drug or carrier is that sick or unhealthy animals will continue to drink water whereas
itself, appropriate drying or other steps may be required. they may not eat. The use of water as the drug medium is limited,

4. Electrostatic charges: fine drug powders will often however, by the solubility of the drug moiety. Since animals drink
develop static charges during particle size reduction and twice as much water as they consume feed, the concentration of the
flow through material-handling systems. These charges drug in the water needs to be only half that of feed. This factor may
need to be minimized to prevent unmixing or loss in even overcome the problem of limited solubility.
distribution throughout the premix and subsequent feed. Automatic metering devices or medication proportions are used

5. pH extremes: these can frequently be compensated for for treating large numbers of animals. The powder medication is
by use of sodium carbonate to neutralize acid mixtures dissolved at the time of administration into water to make a stock
or calcium phosphate monobasic or fumaric acid to solution, which is proportioned into the drinking water system as
neutralize basic mixtures. the water is consumed by the animals. The common dilution in the

United States is one fluid ounce of stock solution (or liquid drug
6. Flow: this is important when automatic premix addition concentrate) to 127 ounces of water, producing a one fluid ounce per

equipment is used in modern feed mills. Bridging (an gallon dilution. Whether a product is formulated as a dry powder,
organized structure of product that impedes flow), which dispensing tablet, or liquid concentrate, the product development/
inhibits addition of the premix to the feed batch, will compounding pharmacist must be concerned with the effects of the
cause the mill to shut down until the correct amount of properties of the diluting water media. Tablet or granule hardness,
premix is added. This shut-down of the mill can cause buffer capacity, pH, and total dissolved solids all play a role in the
considerable consternation to the operators of the mill solubility rate and availability of the drug substance, as well as its
who are producing multiple batches of feed per day. stability [7].

The normal standard of premix usage in feed is one part In addition, dry products are usually formulated with a sugar
medicated premix to 1999 parts of feed. A properly formulated diluent such as lactose or dextrose. The use of these may cause a
premix can be used directly in preparing a medicated feed without build-up of bacteria and fungi in water lines when the sugar level
further dilution. It can be further diluted in the feed mill by the use is high for an extended period of time. In the product development
of in-plant premixes (type B medicated articles), but this would beat laboratory, medicated drinking water samples must be prepared from
the discretion of the feed mill operator. Although the pharmacist may these formulations using a range of hard and soft waters and stored
only infrequently have contact with this particular dosage form, there at 25oC and 37±40o C in metal containers or troughs (galvanized iron
has been a movement to give some feed additive drugs veterinary or rusty metal) to simulate the worst possible conditions of use. The
prescription status, which has been done in several European drug stability in the drinking water should be adequate for the storage
countries. This may have future implications to those pharmacists length of time listed on the label. Consideration also has to be given
practicing in rural areas. when formulating a liquid concentrate using solvents other than water
Drinking water medication of the possibility of precipitation or recrystalization of the drug when

diluted with water. All of the above factors make the formulation of
Oral liquids are one of the easier dosage forms to develop. The animal drinking water products an interesting and challenging task.

main challenges are finding a vehicle that result in adequate chemical Marketed drinking water medications are given in Table 2.
stability while achieving a solution. The first vehicle choice will be
water. Good understandings of the pH and temperature effect on Parenteral dosage forms
solubility are needed to ensure no precipitation of the marketed Parenteral dosage forms and delivery systems include injectables
product when exposed to abrupt changes in temperature and pH. (i.e., solutions, suspensions, emulsions, and dry powders for

If the water does not solubilize the drug, a co-solvent system is reconstitution), intra-mammary infusions, intra-vaginal delivery
next explored. Vehicles to consider include ethanol, propylene glycol, systems, and implants [9].
(low molecular weight), glycerin and triacetin as examples. These can A solution for injection is a mixture of two or more components
be used alone or in combination to give a truly nonaqueous system. that form a single phase that is homogeneous down to the molecular
In some cases cosolvents with oleaginous vehicles may be utilized to level. “Water for injection” is the most widely used solvent for
solubilize the drug [3]. parenteral formulations.

A common form of medicating animals for herd or flock health is A suspension for injection consists of insoluble solid particles

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Table 2: Marketed oral controlled release pharmaceuticals product.
Brand Name Active Ingredient(s) Therapeutic Segment Pack Details Animal Species

Alzonic Albendazole 3% w/v + Niclosamide 10%
w/v Endoparasiticide 500 ml and 1000 ml bottles Sheep / Goat

Solution Closantel 15% w/v Ectoendectoparaticide 30ml, 100ml and 500ml bottles Cattle / Buffalo / Sheep / Goat / Camel /

Pig / Horse
Feed-O-Tas Oranic Acids with silica and bentonite Feed Acidifier Poultry 1 kg and 25 kg bags

Fentas Powder Fenbendazole 25% w/w Endoparasiticide Cattle / Buffalo / Sheep / Goat /
Dog / Camel / Horse 60 gm and 120 gm pack

E-Booster Gluconeogenic precursor + Nicotinamide +
Cyanocobalamin Energy booster Cattle / Buffalo 1 Liter

Table 3: Marketed parenteral controlled release pharmaceuticals product.
Brand Name Active Ingredient(s) Therapeutic Segment Pack Details Animal Species

AC-Vet Ampicillin 1 gm + Cloxacillin 1 gm Anti-Infective 2 gm vial with WFI Cattle / Buffalo

AC-Vet Forte Ampicillin 1.5 gm + Cloxacillin 1.5 gm Anti-Infective 2 gm vial with WFI Cattle / Buffalo

Zubion Buparvaquone 50 mg Anti Protozoal 2ml and 20 ml vials Cattle / Buffalo / Camel / Horse

Anistamin Chlorpheniramine maleate 10 mg/ml Anti-Histaminic 50ml and 100 ml vials Cattle / Buffalo / Sheep / Goat / Dog / Cat / Camel /
Horse / Pig

dispersed in a liquid medium, with the solid particles accounting for A paste of the proper consistency adheres to the tongue or buccal
0.5-30% of the suspension. The vehicle may be aqueous, oil, or both. cavity and is not readily dislodged. The animal will eventually end up
Injectable suspensions are commonly used. swallowing it. Characteristics of a suitable paste formulation are [7]:

An emulsion for injection is a heterogeneous dispersion of one 1. When placed in the palm of the hand and the hand is
immiscible liquid in another; it relies on an emulsifying agent for inverted (palm down), it should remain there without
stability. Parenteral emulsions are rare because it is seldom necessary falling.
to achieve an emulsion for drug administration. 2. When the paste is ejected from the applicator, it should

A dry powder for parenteral administration is reconstituted as break free cleanly when rubbed against a flat surface.
a solution or as a suspension immediately prior to injection. The
principal advantage of this dosage form is that it overcomes the 3. No paste should continue to ooze from the applicator
problem of instability in solution after the dose has been ejected.

Mastitis intra-mammary infusion products are available for 4. The paste or gel should be free from air bubbles or voids.
lactating and non-lactating (dry) cows. Lactating cow intra-mammary 5. Only a minimum of force should be needed to expel the
infusions should demonstrate fast and even distribution of the drug paste from the dispensing device.
and a low degree of binding to udder tissue. These properties result in
lower concentrations of drug residues in the milk [10,11]. Biotene Maintenance Gel (Figure 6) is pet toothpaste that provides

long-lasting protection to your pet’s teeth and gums. The plaque-
Intra-vaginal delivery systems included polyurethane sponges removing gel contains Bio-Active Enzymes that effectively inhibit

containing synthetic progestins; silicone based inserts containing odor-causing bacteria. These 6 enzymes (Lysozyme, Lactoferrin,
the naturally occurring hormone progesterone including: the Glucose Oxidase, Lactoperoxidase, Mutanase and Dextranase) each
PRID, CIDR-B, CIDR 1380 Cattle, CIDR Pig Inserts; electronically have their own unique properties, but the combination provides a
controlled inserts (Intelligent Breeding Device and EMIDD) capable powerful antimicrobial defense system against plaque and bacteria.
of delivering multiple drugs at a predefined time, either pulsed Not only that, but it also relieves, soothes and protects their mouth
or continuous fashion; and a biodegradable insert called the PCL tissues against dryness, irritation, inflammation and redness. The
Intravaginal Insert [12-14]. gentle formulation has a pleasant flavor and is safe for pets of all ages.

The majorities of implants used in veterinary medicines are Contain no Xylitol, alcohol, chlorhexidine or chlorine compounds,
compressed tablets or dispersed matrix systems in which the drug is making it a safe part of your pet’s daily oral care program.
uniformly dispersed within a non-degradable polymer. The three types of vehicles used in formulating a paste or gel are

Marketed parenteral controlled release pharmaceuticals products aqueous bases, oil or oleaginous bases, and organic solvents.
are given in Table 3. An aqueous base is the least expensive vehicle and poses no
Oral pastes and gels toxicity problems. A solution of the drug in water or water and

cosolvent is made. Glycerin, glycols, natural and synthetic gums, and
Pastes and gels are semi-fluid masses that can be administered or polymers are used to increase viscosity, cohesiveness, and plasticity.

from a flexible tube, syringe, package, or other specialized dosing To overcome syneresis, or water separation in the gel, a common
device. The advantage of a paste or gel dosage form is that it cannot be problem with aqueous bases, one can use absorbing materials such as
expelled from the animal’s mouth as readily as a tablet or liquid. Also, microcrystalline cellulose, kaolin, colloidal silicon dioxide, starch, etc.
mass medicating of animals can be achieved rapidly and easily with
a paste medication using a multiple-dose dispenser such as a syringe. Oleaginous bases consist of vegetable oil thickened with agents

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and liquids (solutions, suspension concentrates, suspoemulsion,
and emulsifiable concentrates). Of special interest are transdermal
delivery systems that elicit clinical responses by carrying medications
across the skin barrier to the bloodstream. Examples of these are
transdermal gels and patches that are used in companion animals

A transdermal delivery gel consists of a vehicle, most commonly
pluronic lecithin organogel (PLO gel), which delivers drug via the
transdermal route to the bloodstream. The micellar composition
of PLO gel enhances skin penetration of the pharmaceutical agent
present in the formulation. PLO gel is generally well tolerated
and is nontoxic if ingested. However, not all drugs are suitable for

Figure 6: Biotene veterinarian oral care kit and maintenance oral gel. transdermal application and there are relatively few studies of
the bioavailability of drugs from compounded transdermal gels.

such as aluminum monostearate, colloidal silica, and xanthan gums. Transdermal gels are used to deliver drugs to treat several diseases
The lubricant properties of the oil make these formulations less in dogs and cats, including undesirable behavior, cardiac disease,
adhesive than water bases. and hyperthyroidism. The dose is applied to the inner surface of the

Glycerin, propylene glycol, and polyethylene glycol thickened pinnae, thereby offering ease of administration, especially in cats.
with carboxy vinyl polymers (CarboxamerNF) provide organic A  transdermal delivery patch  typically consists of a drug
solvent bases. Consistencies ranging from soft jelly to peanut butter incorporated into a reservoir, a protective backing layer, a rate-
can be achieved. limiting release membrane, and an adhesive layer for securing the

A paste is administered to an animal volumetrically. The drug patch to the skin. The physicochemical properties of a drug suitable
level and density of the paste must be known to determine the for transdermal delivery ideally include low molecular weight (<500
amount of drug delivered per given volume. This takes trial and error daltons), high potency, water solubility (to facilitate movement of the
in the formulation process to arrive at the volume of paste necessary drug out of the reservoir and to allow passage through the epidermal
to provide the required dose. Sometimes pastes are used in small and dermal layers of the skin), and lipid solubility (to permit
animals by applying them to an animal’s fur on the front paws. The penetration of the stratum corneum of the skin). Fentanyl, a synthetic
animal will lick the paste off to stay clean. opioid agonist, is delivered by transdermal patch in dogs, cats, and
Drenches and tubing products horses.

Horses are administered certain medications by running a There are several unique topical dosage forms for animals. Four
lubricated tube up through the nostrils and down into the stomach. types of which the pharmacist should have a basic understanding or
A funnel attached to the tube is held above the horse’s head and the awareness are: (a) pour- on/spot-on applications, (b) dust bags, (c)
liquid medication is poured down the tube. This is known as “tubing’’. dips, and (d) flea and tick collars5. These are used for treatment and

prevention of internal and external parasites. The control of internal
The normal dose for a horse by this method is approximately 10 and external parasites of companion and food-producing animals has

fluid ounces. It needs to be formulated so that the amount will flow led to the development of specialized dosage forms, delivery systems,
through the tubing (i.e., 6 1/2 ft × 3/8 in.) in 60 seconds. Wetting and application methods that are unique to veterinary medicine.
agents are used to increase flow rate. Thickening or suspending agents
are contraindicated since the formulations will thicken and resist flow Pour-On/Spot-On applications: These liquid products affect
when shear is removed. systemic activity after being poured onto an animal’s backline or

applied as a one-spot concentrate on the animals back or rump.
The administration of a drug to animals by pouring a liquid Some spot-on products now help small animals combat fleas and

medication down an animal’s throat is called “drenching’’. Drenches ticks. These products are generally preferred to flea and tick collars.
are dispensed via syringe or drenching guns. The viscosity should The oils from the drug mix with the pet’s natural oils. They act as a
be adequate to prevent dripping from the syringe during movement neurotoxin against the ectoparasites. In cattle, spot-ons are mainly
from the drug container to the animal. Drenching gun can utilize used for control of grubs and lice. However, there is one pour-on/
formulations that are less viscous since leakage from the gun is not spot-on product (levamisole) that has broad-spectrum anthelmintic
a major problem. Too viscous a product may cause administrator activity. These formulations contain organophosphorus insecticides
fatigue when large numbers of animals are dosed. These drenches or the anthelmintic dissolved in organic solvents, such as dimethyl
and tubing products are often given over extreme ranges of sulfoxide and/ or aromatic hydrocarbons. The advantages of these
temperatures in field conditions. The formulator must take this into formulations are:
consideration when developing the dosage formula and testing it in
the administration equipment. 1. Risk of trauma and inhalation pneumonia associated

with drenching or damage at injection site (for parenteral
Topical dosage forms products) are eliminated.

The topical dosage forms available for treating animals include
solids (dusting powders), semisolids (creams, ointments, and pastes), 2. No special skills are required for application since they

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are administered topically by use of sprays or spotter constructed of concrete or slats to remove dirt from the animals’ feet
bottle (a bottle with a squeeze- on applicator). and for animals to be held in a yard overnight prior to dipping, during

3. Sterile precautions are not necessary. which time they are offered water but no food.

4. Troublesome animals are dosed easily with safety to the Shower dips  are less labor intensive than plunge dips and
person performing the application. are cheaper to operate. A typical shower dip consists of a sump

containing the dip wash, a pump, and a showering pen constructed
5. Speed of treatment is quick. with a concrete floor and fitted with an overhead rotating boom
Dust bags: Cattle are treated with insecticide powders through with nozzles and fixed nozzles near ground level. There are two

use of a device called a dust bag. Dosing is accomplished by the types of shower dips: a conventional shower dip in which the sump
animals brushing against the bag as they walk beside or under it. volume is periodically maintained by adding fresh dip wash, and a
The bag has an inner porous storage bag containing the insecticide constant replenishment shower dip in which a small-volume sump
dust formulation. This is protected from the elements by an outer is continuously filled from a large-volume supply tank to maintain
protective waterproof skirt open to the porous dust bag at the bottom. dip levels. Proper dip management requires attention to the factors

described above for plunge dipping [16]. In addition, all equipment
The cattle can have free-choice application or are forced to use must be functioning properly for the fleece to become saturated. Sheep

dust bags depending upon where they are hung. Forced-use bags are should not be dipped (by either the plunge or shower method) until
hung in doorways, lanes, gateways, etc. Free-choice applications can shearing wounds have healed to avoid clostridial infections or caseous
be achieved by suspending the bags from overhead structures, like a lymphadenitis caused by  Corynebacterium  pseudotuberculosis.
tree or pole. One would be surprised at the will ingness of the majority Moreover, the correct use of bacteriostats is recommended to prevent
of range cattle to come to a free-choice application sit post-dipping lameness caused by Erysipelothrix insidiosa.

Dips: For control of ectoparasites in economic animals, dipping Flea and tick collars: This dosage form will be most familiar to
is an extensively used method of sheep and cattle for external the pharmacist since it is used for companion animals (dogs and
parasites requires a dipping vat, which may be a portable unit or a cats) and is sold in most drugstores, supermarkets, and animal health
permanent in-ground structure shielded from direct sunlight by product centers. There are two types of flea and tick collars, also
roofing. A draining pen located at the exit of the vat allows dip wash known as slow-release pesticide generators: vaporous and powder-
draining off treated animals to return to the vat. Dip chemicals are producing collars. Both contain the insecticide and a plasticized solid
usually formulated as aqueous solutions, emulsifiable concentrates, thermoplastic resin.
or suspension concentrates, all of which are diluted with water
prior to use. The high costs associated with plunge dipping relate The vaporous collar contains a relatively high- vapor-pressure
principally to the costs of chemicals for charging large vats, labor, and liquid pesticide mixed throughout the collar. The pesticide is slowly
the disposal of the hazardous wastes. A dip formulation containing released and fills the atmosphere adjacent to the animal’s surface with
the drug is diluted in a large dipping bath through which the animal a vapor of pesticide that kills the pest but is innocuous to the animal.
is driven. This bath must be long, wide, and deep enough to cause The powder-producing collar contains a solid solution of the
immersion of the animal. The formulation of the ectoparasiticide is drug in the resin. Shortly after the collar is processed, the particles or
challenging. It must not be inactivated by matter that accumulates in molecules of the pesticide migrate from within the body of the resin
the dipping bath and should maintain stability throughout a range of and form a coating of particles, known as “bloom,’’ resembling a dust
concentrations and temperatures. In addition, it must be nontoxic to or powder on the collar surface.
the animal but toxic to the ectoparasites. This dosage form is used in
both large and small animals. Ticks and fleas tend to concentrate in or migrate through the neck

area of the animal. As they do this, they contact the active pesticide
Plunge dips must be managed properly, and the pesticide on or released by the collar and are killed. Powder-producing collars

maintained at the concentration recommended by the manufacturer. have an advantage over vaporous ones in that by the movement of the
Dipping of sheep and cattle is associated with “stripping” of the dog or cat, the powder crystals (bloom) are rubbed or wiped onto the
active ingredient from the dip wash, eg, pesticide loss from the dip fur, which expands the contact area allowing it to continue to control
wash occurring at a greater rate than water loss, and is categorized as the ticks and fleas.
mechanical or chemical. In the case of sheep, mechanical stripping
results from the fleece acting as a sieve toward the active ingredient, Product Quality and Efficacy
with the degree of filtration being primarily determined by particle Before they can be put on the market, the efficacy of veterinary
size. Chemical stripping is due to the preferential absorption of products is confirmed by trials under field conditions [17].
pesticide by the fleece. To counteract stripping, a complex dip
management regimen that involves reinforcement and ‘‘topping-up” High standards of purity and consistency
is used. Reinforcement refers to the addition of undiluted chemical Pharmaceutical quality is an essential ingredient of product
product to the dip without the addition of water, whereas topping- safety, and requires the product to be manufactured according to
up refers to the addition of water and undiluted chemical product specific standards of purity and consistency. These standards apply
to the dip vat to return the volume to the starting level. Proper dip throughout the production and formulation process. Stability studies
management also minimizes the contamination of the dip with ensure that the product retains its potency, efficacy and safety, for the
organic matter. This requires that the race leading to the vat is full duration of the shelf-life.

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Ramteke KH Austin Publishing Group

Testing methods are continuously being improved with the feed and are usually issued as pellets, granules or powders.
The pharmaceutical manufacturer is required to guarantee If issued as granules, these are free flowing and free from aggregates.

that a medicine contains only those ingredients that are specified Suitable precautions are taken during manufacture for ensuring that
in the data file – nothing more, nothing less – and in exactly the the premix is homogeneous.
proportions indicated. Analytical test methods used to achieve this Unless otherwise stated in the individual monograph, the
are continuously being improved. concentration of the premix in medicated feedstuffs is not less than

The animal health industry has, on own initiative, introduced 0.5%.
sterility tests and visual inspection of random samples as additional Tests
control measures. As an example of the efforts made to guarantee Loss on drying: Not more than 15.0 per cent, determined on 3 g
consistent product quality, water used for dissolving the active by drying in an oven at 105º for 2 hours.
substance of a medicine is distilled twice, sterilized and then kept at
85°C until used. Labeling: The label states (1) the strength in terms of the amount
The product will live up to its claims of active ingredient(s) as a percentage; (2) the category of animal

for which the premix is intended to be used; (3) the directions for
Data must also be provided to prove that the product meets the preparation of the medicated feed; (4) where applicable, the

a specified level of efficacy in treating or preventing a particular minimum interval between the stoppage of feeding of the diluted
medical condition. Thus the customer can be assured that, when used premix and the slaughter of the animal for human consumption;
as directed (correct dose-rate, frequency and duration of treatment), (5) any special precautions to be taken for use of the premix; (6) the
a product will meet its label claims. To support this claim, a product storage conditions; (7) the date after which the preparation is not
is tested extensively in the laboratory, in disease challenge studies and intended to be used.
finally in field trials, which must demonstrate that it works under
conditions of practical field use. Veterinary oral liquids: Veterinary oral liquids intended for

administration in large animals may also be called Drenches.
The leaflet is part of the product

An animal health product does not consist of the medicine Veterinary oral powders: Veterinary Oral Powders are intended
alone. The product name together with its label and leaflet (giving for oral administration, usually after dilution in drinking water or the
indications, contra-indications, warnings and withdrawal periods) feed. They may be in the form of soluble or wettable powders.
are also essential parts of the product and its registration process. The Labeling: The label states that (1) for single dose containers,
registration authorities must also approve these and any changes to the name and quantity of active medicament(s) per container;
them. (2) for multiple dose containers, the name and quantity of active

Dosage Forms of Active Pharmaceutical Ingredients apply to all medicament(s) by weight; (3) the name of any added antimicrobial
veterinary dosage forms or preparations of the type defined. However, preservative(s); (4) the directions for use of the preparation.
a valid interpretation of the appropriateness of a test or requirement Intramammary infusions: Intramammary Infusions for
for compliance with the test given under each dosage form [18]. Veterinary Use; Intramammary Injections. Intramammary Infusions

Dip concentrates: Dip concentrates are preparations for the are sterile products intended for injection into the mammary gland
prevention and treatment of ectoparasitic infestations of animals. through the teat canal. They are solutions, emulsions or suspensions
They contain one or more medicaments, usually in the form of wet or semi-solid preparations containing one or more active ingredients
table powders, pastes or solutions from which diluted suspensions or in a suitable vehicle. They may contain stabilizing, emulsifying,
emulsions are prepared by appropriate dilution with the recommended suspending and thickening agents. If sediment is formed in a
liquid. The diluted preparations are applied by complete immersion suspension, it is readily dispersible on shaking. In emulsions, phase
of the animal or by spraying, as appropriate. They contain suitable separation may occur but this is readily miscible on shaking. There
antimicrobial preservatives. are two main types of Intramammary Infusions. One is intended for

administration to lactating animals as qualified by the term Lactating
Labeling: The label states (1) the name(s) and proportion(s) Cow/Buffalo and the other, qualified as Non-lactating or Dry Cow/

of medicament(s); (2) the name and proportion of any added Buffalo, is intended for administration to animals at the end of
antimicrobial preservative; (3) the name and quantity of the diluent lactation or during the non-lactating period for the prevention or
and the manner of preparing the diluted dip solution or spray; (4) treatment of infection during the dry period. Intramammary Infusions
any special precautions to be taken for use of the preparation; (5) the are prepared by dissolving or suspending the sterile medicaments in
storage conditions; (6) the date after which the preparation is not the sterilized vehicle using aseptic precautions, unless a process of
intended to be used. If the preparation contains an organophosphorus terminal sterilization is employed.
compound the label also states (1) that the preparation contains an
organophosphorus compound; (2) and special precautions on the use Container: Intramammary Infusions are usually supplied in
of the preparation. single dose containers for administration into a single teat canal of an

animal. If supplied in multiple dose containers, aqueous preparations
Premixes: Premixes are mixtures of one or more active ingredients contain an antimicrobial preservative in adequate concentration

with suitable bases intended for mixing with feedstuffs before except when the preparation itself has antimicrobial properties. The
administration to the animals. They are used to dilute medicament(s) containers are made as far as possible from materials that meet the

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Ramteke KH Austin Publishing Group

requirements for Parenteral Preparations intended for use in human by farmers. Thus farmed animals would benefit immensely from
beings. The containers are sealed so as to exclude micro-organisms immunization with a single dose vaccine through the use of a
and each container is fitted with a smooth, tapered nozzle to facilitate controlled release technology. However, the case of controlled release
the introduction of the infusion into the teat canal. The containers are of veterinary vaccines is interesting since, unlike other preventative
sterilized and filled aseptically unless the preparation is subjected to a or therapeutic drugs which may be directed toward a single biological
process of terminal sterilization. target, the aim is to present to the immune system a package consisting
Tests of an immunogen and immunostimulatory molecules in a particular

manner that will result in germane and sustained immunity. This
Sterility: Intramammary Infusions comply with the test for requires thoughtful presentation of antigen to the immune system in

sterility, using Method A or B, as appropriate, using the contents of the context of appropriate immune signals. Many attempts have been
10 containers mixed thoroughly before use in the test. Use for each made by formulation scientists to achieve this aim using a pulsed
medium 0.5 to 1.0 g or 0.5 to 1.0 ml, as appropriate, of the mixed delivery system [19-21].

Storage: Store in sterile, single dose or multiple doses, tamper

evident containers. Veterinary pharmaceuticals serve an important role in preserving
and restoring animal health, thereby also enhancing human wellbeing.

Labeling: The label states (1) the strength in terms of the weight Efficient development of safe and effective new animal drug continued
or the number of Units of activity of the active ingredient(s) or that availability of approved products is essential to maintenance of
may be expressed from the container using normal techniques; (2) animal health and productivity. For animal companions, veterinary
whether the preparation is intended for use in lactating cow/buffalo pharmaceuticals are used to treat a range of disease condition similar
or in dry or non-lactating cow/buffalo; (3) for Intramammary to those of human patients.
Infusions (Non-lactating or Dry Cow/Buffalo), that the preparation
is not intended for use in lactating animals; (4) in the case of infusions References
in multiple dose containers, the name of any added antimicrobial 1. Hunter RP, Isaza R. Zoological pharmacology: current status, issues, and
preservative. potential. Adv Drug Deliv Rev. 2002; 54: 787-793.

2. Desmond B. Veterinary Dosage Forms. In: Encyclopedia of Pharmaceutical
Veterinary parenteral preparations: Veterinary Parenteral Technology. 3rd edn. London: Informa Healthcare. 2007; 6: 1238-39.

Preparations prepared with oily vehicles are not meant for intravenous
3. Rathbone MJ, Foster TP. Veterinary Pharmaceutical Dosage Forms.

administration but are suitable for intramuscular or subcutaneous Alexander T, Florence, Juergen Siepmann, editors. In: Modern Pharmaceutics.
use. Veterinary Parenteral Preparations comply with the appropriate Applications and Advances; Drugs and the Pharmaceutical Sciences Series.
requirements for Parenteral Preparations (Injections) that are given Informa Healthcare. USA. 2009; 293-328.
in the chapter on General Monographs on Dosage Forms of Active 4. Rathbone MJ, Gurny R. Controlled Release Veterinary Drug Delivery:
Pharmaceutical Ingredients. biological and Pharmaceutical Considerations. Elsevier Science BV.

Amsterdam. The Netherlands. 2000; 375.
Veterinary tablets: Veterinary tablets are usually solid, circular

5. Thombre AG. Oral delivery of medications to companion animals: palatability
cylinders the end surfaces of which are flat or biconvex and the edges considerations. Adv Drug Deliv Rev. 2004; 56: 1399-1413.
of which are beveled except that those weighing 5 g of more may be

6. Tribble TB. Feed Flavor and Animal Nutrition. AgriAids. Inc, Chicago, IL.
elongated or biconical. 1962.
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Disintegration: The test may have to be suitably modified in dosage forms. 4th edn. Gilbert S, Banker, Christopher T Rhodes, editors. In:
Modern Pharmaceutics. Drugs and the Pharmaceutical Sciences Series.

the case of large tablets; the discs may have to be omitted because Marcel Dekker: New York. 1995; 121: 725-33.
they would otherwise be dislodged from the disintegration tubes.

8. The United States Pharmacopeial Convention Pharmacopeial Forum IN-
It may also be necessary to adjust the volume of the disintegration PROCESS REVISION. 2009; 35: 1281-1283.
medium so that the tablet does not break the surface of the medium
at the top of the upstroke, care being taken to apply the minimum 9. Drug Dosage forms in Veterinary Medicine.

practical volume of liquid for this purpose. For certain tablets where 10. Rathbone MJ. Delivering drugs to farmed animals using controlled release
the diameter of the tablet may not permit adequate movement of science and technology. IeJSME. 2012; 6: S118-128.

the disintegration medium, the apparatus and the method should be 11. Medlicott NJ, Waldron NA, Foster TP. Sustained release veterinary parenteral
suitably modified. products. Adv Drug Deliv Rev. 2004; 56: 1345-1365.

12. Brayden DJ, Oudot EJ, Baird AW. Drug delivery systems in domestic animal
Veterinary vaccines: A major cost to farmers results from the species. Handb Exp Pharmacol. 2010; 79-112.

morbidity and mortality caused by infectious diseases that can be
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prevented or improved by vaccination. However, vaccines need to commercial challenges and academic opportunities. Curr Drug Deliv. 2009;
be given at least twice and, depending on the duration of immunity 6: 383-390.
required, booster doses need to be given at intervals as frequently as 14. Shane Burggraaf, Bunt CR, L Macmillan K, Rathbone MJ. Conceptual and
every 3 months (though more usually 12 months). The high costs commercially available intravaginal veterinary drug delivery systems. Adv
associated with treating animals (herding, etc.,) results in the problem Drug Deliv Rev. 1997; 28: 363-392.
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application of veterinary drugs and parasiticides. J Am Vet Med Assoc. 1997; 19. Cleland JL. Single-administration vaccines: controlled-release technology to
210: 1288-1289. mimic repeated immunizations. Trends Biotechnol. 1999; 17: 25-29.

16. Rathbone MJ, Martinez MN. Modified release drug delivery in veterinary 20. Langer R, Cleland JL, Hanes J. New advances in microsphere-based single-
medicine. Drug Discov Today. 2002; 7: 823-829. dose vaccines. Adv Drug Deliv Rev. 1997; 28: 97-119.

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Austin Therapeutics – Volume 1 Issue 1 – 2014 Citation: Ramteke KH, Joshi SA, Dighe PA and Kharat AR. Veterinary Pharmaceutical Dosage Forms: A
ISSN: 2472-3673 | Technical Note. Austin Therapeutics. 2014;1(1): 10.
Ramteke et al. © All rights are reserved

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