Controlled release of sirolimus from a multilayered PLGA stent matrix

Biomaterials. 2006 Nov;27(32):5588-95. doi: 10.1016/j.biomaterials.2006.07.016. Epub 2006 Aug 1.

Abstract

The release of sirolimus from a bi-layer biodegradable polymeric film is reported in this study. Approved drug-eluting metal stents use a thin polymer coating to control drug release, but the degree of control is limited. In a fully polymeric stent, the use of multilayers allows a range of release kinetics. A bi-layer system, with PLLA as the supporting layer and PLGA as the drug-eluting layer, was used in this study to simulate release of sirolimus from a stent. The results show that the release of sirolimus is diffusion and degradation-controlled, and that the amount of sirolimus loading does not affect its release kinetics. The release of sirolimus is, however, accelerated by the addition of a plasticizer, such as PEG, as water uptake is increased. An increased water uptake increases polymer degradation, and changes the dominant mode of release to degradation-control. The release of sirolimus can, on the other hand, be retarded by using a coating of a biodegradable polyester with a lauryl ester end group. Therefore, multilayered systems offer many options for controlling sirolimus release over months.

MeSH terms

  • Delayed-Action Preparations*
  • Diffusion
  • Kinetics
  • Lactic Acid / chemistry*
  • Molecular Structure
  • Molecular Weight
  • Polyglycolic Acid / chemistry*
  • Polylactic Acid-Polyglycolic Acid Copolymer
  • Polymers / chemistry*
  • Sirolimus* / administration & dosage
  • Sirolimus* / chemistry
  • Stents*

Substances

  • Delayed-Action Preparations
  • Polymers
  • Polylactic Acid-Polyglycolic Acid Copolymer
  • Polyglycolic Acid
  • Lactic Acid
  • Sirolimus