ABSTRACT
Animals provide us with companionship (e.g., dogs and cats), recreation (e.g., horses),
food (e.g., cattle and pigs), and manual labor (whether an elephant carrying logs in
Thailand or a hunting dog retrieving a downed pheasant in South Dakota). Just like
humans these animals receive medicines to keep them healthy, and the reasons for
producing single-dose veterinary dosage forms is the same as those in humans; to permit
delivery of an active in a form that is effective, safe, and able to be handled and
administered by the end user. However, when one extends that comparison to long-acting
dosage forms, the reasons for developing such a system differs between humans and
animals. In the case of humans, the reasons for developing a drug into a long-acting
delivery system include the reduction of dose frequency to improve patient compliance, or
to improve the efficiency of therapy and thereby improve the health of the patient. 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 animals from
repeated administration and to reduce the cost of treatment in terms of money and time
spent by the end user on drug administration. These reasons do not impact on the science
used to develop such dosage forms, but they do impact heavily on the outcomes such as
the size, shape, volume administered, etc. of the dosage form.
