Development and characterization of an intraocular biodegradable polymer system containing cyclosporine-A for the treatment of posterior uveitis

Abstract

The aim of this study was to synthesize and characterize the biodegradable intraocular implants based on poly (D,L-lactide-co-glycolide) (PLGA 75:25) with Cyclosporine-A (CyA) and to evaluate their in vitro drug delivery profile. Thermal analysis was conducted by using Thermogravimetry (TG) and Differential Scanning Calorimetry (DSC). Phase analysis and crystallinity of the polymer-CyA samples were assessed through X ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). Finally, microstructure and morphology of the systems were investigated by Scanning Electron Microscopy (SEM). The results showed that CyA was successfully incorporated into PLGA network with drug loading of approximately 31.6%. Also, based on FTIR and thermal analyses (TGA/DSC) no significant physical-chemical interaction was detected at the micro-nanoscale level between polymer/drug. SEM micrographs have indicated a uniform drug distribution in PLGA matrix. XRD patterns have showed that the incorporated semi-crystalline structure of CyA has not significantly altered the polymeric mainly amorphous network. In addition, the results have confirmed the chemical and biological drug stability, the drug distribution into the polymeric matrix and the possibility of cyclosporine prolonged delivery system profile.

Novel use of superdisintegrants as viscosity enhancing agents in biocompatible polymer films containing griseofulvin nanoparticles

“…On the other hand, the films containing traditional viscosity enhancing agents, i.e., F-GG, F-XG, and F-Pectin display slower release; t 80 is about 26, 46, and 58 min, for F-GG, F-Pectin, and F-XG, respectively. These observations for the traditional viscosity enhancing agents are generally in agreement with literature findings[68][69][70][71][72][73][74]. Films containing gums or pectin swell upon contact with media, which creates a diffusion barrier for the drug release resulting in slower drug release.…”

Sistemas biodegradáveis contendo acetato de prednisolona para administração orbitária

“…Embora a concentração teórica da formulação seja de 10%, raros são os casos em que 100% do fármaco é efetiva-mente encapsulado durante a formação de microesferas poliméricas e o teor de encapsulação encontrado pode ser considerado bastante satisfatório quando comparado com outros estudos (4,7) . A morfologia da superfície de sistemas poliméricos tem um papel importante no seu processo de degradação e de liberação dos fármacos nele presentes, pois a presença de poros ou canais na matriz pode permitir uma difusão do fármaco possivelmente não controlada pela velocidade de degradação do polímero (12) . A quase ausência de poros observada nas MEs incubadas durante um mês sugere que o AP liberado durante este período é decorrente basicamente da difusão do fármaco que ficou adsorvida na superfície das MEs.…”

Design and characterization of a multi‐layered polymeric drug delivery vehicle

“…The low concentrations of BSA measured in the solution could be the result of loosely entrapped BSA molecules on the PLGA polymeric surface that passively diffused into solution. [27][28] Saliba et al [27] reported that PLGA polymeric particles showed complete mass loss of 100 % over the temperature range of 247-378 8C, indicating that the observed mass loss of DP and DPAP microparticles could be the result of PLGA degradation. Thermogravimetric Analysis of DP and DPAP Micro-particle Both thermogravimetric analysis and differential scanning calorimetric analysis were used to study the thermal stability of DP and DPAP micro-particles.…”