Controlled sustained delivery of monensin in cattle: The monensin R.D.D.®

Biodegradable polymers and their potential use in parenteral veterinary drug delivery systems

Biodegradable polymers have been extensively studied for numerous drug delivery systems for human health purposes. The ever-increasing value of animals to human society allows the application of pharmaceutical developments in the veterinary field from those developed in human medicine. Although many similarities between the human and animal health industries exist there are also notable differences. This paper provides an insight into the animal health market with regard to the challenges and special considerations associated with veterinary drug delivery. It also gives an overview of biodegradable polymers that are used or have been tested in the veterinary field. The purpose of this paper is to highlight some recent developments in this area and to investigate the directions in which veterinary pharmaceutics is heading. In particular, examples of existing biodegradable veterinary drug delivery systems are presented together with applications including intravaginal devices, injectables and implantable systems.

Formulation and technology aspects of conrolled drug delivery in animals

In the veterinary field, the development of new routes of administration or new delivery systems capable of controlling the release of drugs are of considerable interest. Because of the large number of food-producing animals and the unique problems associated with the administration of drugs to these animals, the potential markets are huge and will only be fully realized if improvements to old dosage forms lead to practical and effective formulations. This review intends to summarize the state of the art in the field of veterinary controlled and/or prolonged release systems.

Intraruminal devices

Intraruminal boluses are drug delivery devices designed to provide long term delivery of drug to the reticulo-rumen compartments of ruminant animals. This cavity is the site of the bacterial fermentation and breakdown of foodstuffs and represents an ideal site for the long term delivery of drugs and nutrients to these grazing animals. Often such animals are 'turned out' in the spring to spend much of the spring, summer and autumn seasons grazing open range. As such, the administration of drugs during the grazing season is complicated by the need to first retrieve the animals prior to drug administration. Long term delivery of drug circumvents this problem providing for decreased costs and improved efficiencies for the farmer. Numerous types of delivery devices have been developed to meet this need. This review summarizes the various approaches that have been developed, provides information on the critical design features and reviews the relevant anatomy and physiology of these animals. Some comments are provided regarding needed future developments for this class of drug delivery system.