Controlled degradation of multilayered poly(lactide‐co‐glycolide) films using electron beam irradiation

Abstract

The ability to undergo predictable and controlled degradation allows biopolymers to release prescribed dosages of drugs locally over a sustained period. However, the bulk or homogeneous degradation of some of these polymers like poly(L-lactide) (PLLA) and poly(lactide-co-glycolide) (PLGA) work against a better controlled release of the drugs. Inducing the polymers to undergo surface erosion or layer-by-layer degradation could provide a better process of controlled drug release from the polymers. This study has demonstrated that surface erosion degradation of PLGA is possible with the use of a multilayer film system, with PPdlLGA [plasticized poly (D,L-lactide-co-glycolide) (PdlLGA)] as the surface layers and poly(L-lactide-co-glycolide) as the center layer. The use of the more hydrophilic PPdlLGA as the surface layer resulted in a faster degradation of the surface layers compared to the center layer, thus giving a surface erosion degradation effect. The rate of surface degradation could also be controlled with electron beam (e-beam) radiation, where e-beam irradiation was shown to alter the degradation time and onset of polymer mass loss. It was also shown that the more highly irradiated PPdlLGA surface layers had an earlier onset of mass loss, which resulted in a faster reduction in overall film thickness. The ability to control the rate of film thickness reduction with different radiation dose promises a better controlled release of drugs from this multilayer PLGA film system. 2007 Wiley Periodicals, Inc. J Biomed Mater Res 84A: [980][981][982][983][984][985][986][987] 2008

Manipulation of process parameters to achieve different ternary phase microparticle configurations

“…Previous studies have shown that the degradation behavior of multi-layer polymer films differs from that of single layer polymer films, with the degradation of the top polymer layer accelerating hydrolysis of the underlying layers [12,13]. Thus it is postulated that a composite multi-layer or multi-phase microparticulate system may also possess unique hydrolytic degradation characteristics that differ from single walled particles.…”

Drug Release From Irradiated PLGA and PLLA Multi-Layered Films

“…27,28 Preliminary drug release results from these irradiated polymer films also show that radiation accelerates the onset (or reduces the lag phase) of drug release from these bulk degrading polymers (results not published). At the same time, ebeam irradiation had also been shown to elicit surface degradation characteristics from single layer 29 and multi-layer non-drug loaded PLGA films, 30 which incidentally may allow for a better control and predictability of drug release rates from PLGA. 31 Controlling rate of hydrolytic degradation is desirable in order for drug delivery to be effectively applied.…”

Surface modification of poly(l-lactic acid) with biomolecules to promote endothelialization

“…Our group has demonstrated enhanced endothelialization rate in vitro by several physical surface modification methods, such as salt-leaching 12 and lithography 13 to create nanosized surface features. Zhu et al [14][15][16][17] used aminolysis to introduce primary amine groups on the surface of PLA, PLGA, and PCL, followed by introduction of gelatin, chitosan, and collagens through glutaraldehyde or layer-by-layer assembly.…”