M. Pastusiak

Local delivery system of doxycycline hyclate based on ϵ-caprolactone copolymers for periodontitis treatment

The aim of the study was to evaluate kinetics of doxycycline hyclate release from polymeric bioresorbable implants and to examine suitability of this system for local treatment of periodontitis. Selected trimethylene carbonate/ϵ-caprolactone (TMC/CL) and glycolide/caprolactone (GL/CL) copolymers were synthesized and used as carriers in the form of small elastic rings with 5 wt% and 10 wt% doxycycline hyclate content, or in the form of flakes obtained through electro-spinning technique. The release of the drug under in vitro conditions has been tested. The study has shown that equimolar TMC/CL copolymer loaded with 10 wt% of doxycycline hyclate appears to be the most suitable copolymer for assumed system. The drug release proceeds mainly by diffusion of medium into the polymeric matrix and then the drug is washed out. Daily validation of doxycycline doses released by the system should ensure accurate course of the therapy.

Effect of vascular scaffold composition on release of sirolimus

Graphical abstract Figure. No Caption available. Abstract Despite extensive development of bioresorbable drug‐eluting vascular scaffolds it is still challenging to achieve controlled drug delivery. The lack of capacity for adjusting the drug dose and inadequate release behavior are one of the main reasons of the side effects. However, so far, mainly biodegradable drug‐eluting coatings of metallic stents have been studied in regard to explain drug release mechanisms. The objective of this study was to develop degradable polymer coatings applicable to bioresorbable polymer‐based scaffolds. Moreover, a detailed analysis of sirolimus release and scaffold degradation has been conducted. Coating layers of the same composition were applied by the same method on the surface of two different kinds of scaffolds in order to explain the effect of scaffold structure on release process. The developed coatings showed controlled release of antiproliferative agent with elimination of burst effect. However, differences in drug release profile from two kinds of scaffolds were observed. Scaffold composed of polymer with higher lactide content showed slower and bi‐phasic, erosion‐controlled release of sirolimus. On the contrary, sirolimus release from scaffold composed of polymer with lower content of lactide was mainly controlled by diffusion. These results demonstrate that characteristics of scaffold is another crucial factor that must be considered in further development of bioresorbable vascular scaffolds (BRS) with controlled release of antiproliferative agent.