Encapsulation and modified-release of thymol from oral microparticles as adjuvant or substitute to current medications

tThe aim of this study was to encapsulate, thymol, in natural polymers in order to obtain (i) taste mask-ing effect and, then, enhancing its palatability and (ii) two formulations for systemic and local deliveryof herbal drug as adjuvants or substitutes to current medications to prevent and treat several humanand animal diseases. Microspheres based on methylcellulose or hydroxypropyl methylcellulose phtha-late (HPMCP) were prepared by spray drying technique. Microparticles were in vitro characterized interms of yield of production, drug content and encapsulation efficiency, particle size, morphology anddrug release. Both formulations were in vivo orally administered and pharmacokinetic analysis wascarried out. The polymers used affect the release and, then, the pharmacokinetic profile of thymol. Encapsulation into methylcellulose microspheres leads to short half/life but bioavailability remarkablyincreases compared to the free thymol. In contrast, enteric formulation based on HPMCP shows verylimited systemic absorption. These formulations could be proposed as alternative or adjuvants for con-trolling pathogen infections in human or animal. In particular, methylcellulose microspheres can be usedfor thymol systemic administration at low doses and HPMCP particles for local treatment of intestinalinfections.