Oral controlled-release formulation in veterinary medicine

The development of controlled-release dosage forms (CRDFs) is highly desirable both from a convenience and compliance perspective. Furthermore, these formulations release drugs at a prescribed rate, leading to relatively constant blood drug concentrations or to pulse dosing. Another benefit is the ability to administer medications in infrequent regimens. For example, antimicrobial agents generally require very frequent administration regimens. In recent years, the pharmaceutical industry has realized the potential of this treatment modality and efforts have been made to develop a variety of CRDFs exclusively for veterinary use. While there are a number of controlled-release products available for veterinary applications, only a limited number of therapeutic niches (such as the application of antiparasitic drugs in cattle) are associated with products that have been developed as oral controlled-release products. In addition to reviewing potential new therapeutic areas where oral controlled-release products can be applied in veterinary medicine, this article reviews differences in the gastrointestinal tracts of various species and the significance of the dissimilarity in the development of CRDFs. Technological aspects involved in veterinary CRDFs are also assessed.