Drug delivery systems for intra-articular treatment of osteoarthritis.

INTRODUCTION: Intra-articular (IA) drug delivery is very useful in the treatment of osteoarthritis (OA), the most common chronic joint affliction. However, the therapeutic effect of IA administration depends mostly on the efficacy of drug delivery. AREAS COVERED: The present article reviews the current status of IA therapy for OA treatment as well as its rationale. Outlines of drug delivery parameters such as release profile, retention time, distribution, size and transport that influence the drug's biological performance in the joints are summarized. New delivery systems, currently under investigation, including liposome, nanoparticle, microparticle and hydrogel formulations are introduced. Functionalized drug delivery systems by targeting and thermoresponsiveness that are being investigated for OA treatment via IA therapy are also addressed. EXPERT OPINION: Several delivery systems, including liposome, microparticles, nanoparticles and hydrogels, have been investigated for the sustained drug delivery to the joints. These can be advanced by the use of functionalized drug delivery systems that can lead targeting to specific regions and thermoresponsiveness for prolonged drug release in the joints. Further advances will bring forth new biocompatible and biodegradable materials as a drug carrier or new combination regimens. Future innovations in this field should be directed toward the development of adapted delivery systems that can induce tissue regeneration in OA patients.