What are the dosage forms of veterinary drugs?

Veterinary drugs can be categorized into active pharmaceutical ingredients (APIs) and formulations. APIs are generally not used directly for the prevention and treatment of animal diseases, mainly because they come in large packages, have a single formulation type, are inconvenient to use, and are difficult to store. This is precisely why formulations were developed. Formulations facilitate the transportation and storage of drugs, making them more convenient and practical to use. Moreover, by adding special excipients, synergistic agents, or employing specialized manufacturing processes, it’s possible to enhance the absorption and bioavailability of the drug, thereby improving its therapeutic efficacy.
1. Liquid preparations
1) Liquid injections—commonly referred to as “water injections”—include sterile aqueous solutions, suspensions, emulsions, and the like. These are typically administered via injection, such as oxytetracycline injection, astragalus polysaccharide injection, and ceftiofur suspension.
2) Solution preparations: The solvents used are typically water, alcohol, oil, and the like. These preparations can only be administered orally or applied topically, such as neomycin sulfate solution, enrofloxacin solution, glutaraldehyde solution, hydrogen peroxide solution, and liquid vitamin oils.
3) Tinctures and spirits: A tincture is a solution obtained by extracting crude drugs with ethanol—for example, gentian tincture, citrus peel tincture, strychnine tincture, cinnamon tincture, rhubarb tincture, and iodine tincture. A spirit, on the other hand, is an ethanol solution prepared from volatile medicinal ingredients—for example, camphor spirit and aromatic ammonia spirit.
4) Compound Preparations: Compound preparations refer to aqueous solutions or suspensions made from two or more drugs, whether soluble or insoluble—for example, Compound Licorice Preparation and Qingjie Compound Preparation.
5) Oral Chinese medicine liquids: Also known as decoctions or infusions, these are solutions primarily made by extracting Chinese medicinal herbs. Examples include Qingwen Jiedu Oral Liquid, Shuanghuanglian Oral Liquid, and Maxing Shigan Oral Liquid.
6) Emulsions or Lotions: These are primarily emulsion suspensions prepared by combining a drug with an oil, an emulsifier, and water—for example, oil vaccines and emulsified cod liver oil. Lotions, on the other hand, are solutions made by combining irritant drugs with ethanol or oil—for example, turpentine lotions.
7) Herbal extract liquid extracts: These are primarily liquids obtained by concentrating the extracts from Chinese herbs. Examples include Scutellaria baicalensis liquid extract preparations.
8) Pour-on preparations: Also known as topical transdermal agents, these are mostly used for external parasite control in animals, such as ivermectin pour-ons and moxidectin pour-ons.

2. Gas preparations:
In veterinary clinical practice, most aerosols are administered via environmental application, topical application, or respiratory administration. However, their use is not widespread; examples include ivermectin spray, scabies aerosol, and povidone-iodine aerosol.
3. Semi-solid dosage forms:
1) Ointments: These are thick, paste-like dosage forms prepared by mixing drugs with excipients such as petrolatum and oils. They are mostly used topically, examples include ichthammol ointment, erythromycin ointment, and ketoconazole ointment.
2) Pastes: These are typically prepared by mixing oil-based agents with water-soluble solid powders, with the powder content exceeding 25%. Examples include zinc oxide paste and calcium hydroxide paste.
3) Licking preparations: These are formulations made by mixing a drug with an appropriate amount of excipients (such as starch, syrup, or honey).
4) Extract paste: A paste obtained by further concentrating the extract from oral liquid preparations of traditional Chinese medicine, such as licorice extract paste.