John R. Cardinal

Intraruminal controlled release boluses

Publisher Summary The delivery of drugs to ruminants can be a costly process since these animals are placed in remote areas. to minimize the number of times these animals must be handled during grazing periods, numerous products have been devised to provide very long-term delivery of drugs to them. This chapter reviews systems that have been designed to deliver drugs to the rumen of grazing animals focusing on those product concepts that have been commercialized in various countries of the world. The mechanisms of drug delivery utilized to achieve these product concepts vary widely. In some systems the delivery rate is largely free of local environmental influences such as the osmotic mechanism associated with the IVOMEC® SR bolus. In others the rate is strongly dependent on the local environmental factors such as the erosion-based systems utilized in various nutritional and antibacterial delivery systems. This chapter focuses on the pharmaceutical and clinical performance of these products.

Mechanisms of drug release from veterinary drug delivery systems

Publisher Summary This chapter presents an overview of controlled drug delivery system designs which exist in the veterinary literature and reviews details of the mathematical models for the description of drug release from such systems. The aim of the chapter is to describe models that aid in the understanding of drug release from veterinary drug delivery systems and to highlight how knowledge of the mechanism of release can be used to optimize such delivery systems. This chapter briefly describes the design principles of various veterinary drug delivery systems. It describes the mechanism of release, defines the physical model for drug release, and details the kinetics of drug release from such delivery systems. Overall, the chapter demonstrates how an insight into the mechanism of release of drugs from controlled delivery systems will aid their design, development, and optimization.