Encapsulation of Opiorphin in Polymer-coated Alginate Beads for Controlled Delivery and Painkilling

Abstract
Opiorphin (Oph) is a naturally produced endogenous peptide with a strong analgesic effect, superior to that of morphine, and without the severe side effects that morphine and morphine-like drugs exert. However, despite its strong therapeutic potential, the short duration of action, probably due to its low chemical stability and rapid degradation by the peptidases in the bloodstream, represents a serious obstacle to the Oph use into clinical practice. In this work a novel approach to construct Oph-loaded particles as a platform for its delivery has been developed. Gel beads loaded with Oph were synthesized from alginate, a naturally occurring biodegradable anionic polysaccharide, and coated with polyelectrolyte multilayers (from natural polyelectrolytes (chitosan and hyaluronic acid) and synthetic polyelectrolytes (poly(allylamine hydrochloride) and poly(styrene sulfonate)) or hybrid polyelectrolyte-graphene oxide multilayers. All coated Oph-loaded alginate beads show prolonged drug release compared to the non-coated ones, but the extent of the prolongation depends on the type of the coating. We expect that the successful encapsulation of opiorphin in biodegradable particles will provide an opportunity for the development of adequate drug delivery system with effective and prolonged analgesic activity and will offer a new alternative for pain management.