[Controlled Veterinary Drug Delivery Systems against Parasitic Infection]

Parasitic infections, especially the gastrointestinal and lung nematode infections, are most common in livestock in temperate areas, and it is the major constraints affecting livestock production. In grazing season, outdoor activities of animals cause inconvenience to the application of antiparasitic drugs. Therefore, controlled drug delivery systems can prolong the effect time and reduce the difficulty of drug administration. This review summarizes several types of long-term delivery devices and dosage forms including intraruminal devices, long-acting injectables, in-situ forming implants, novel microparticles and nanoparticles. Their advantages and drawbacks are dicussed.