Experimental Studies and Modeling of the Degradation Process of Poly(Lactic-co-Glycolic Acid) Microspheres for Sustained Protein Release.

Paolo Antonio Netti,Marco Biondi,Mariaenrica Frigione

doi:10.3390/polym12092042

Paolo Antonio Netti, Marco Biondi + Show 1 more

Open Access

https://doi.org/10.3390/polym12092042

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Abstract

In this study, poly(lactic-co-glycolic acid) microspheres (PLGA MS)for controlled protein release by double emulsion-solvent evaporation were produced and characterized for their morphological and technological features. MS autocatalytic degradation was described by a mathematical model based on a Michaelis and Menten-like chemical balance. Here, for the first time MS degradation was correlated to the advancement of MS degradation front with respect to the degraded radius, derived from mass loss experiments. The model can satisfactorily describe the kinetics of advancement of the degradation front experimentally derived for all MS formulations, especially when produced at higher PLGA concentrations.

Highlights

Synthetic and natural polymers normally degrade during their service-life, due to the exposure to different environmental conditions
The delivery of drugs from systems based on degradable biomaterials proved to offer important advantages, such as controlled drug release kinetics, which correlates with limited oscillation of drug concentration in blood, a reduction of number of drug administration, and an overall improvement of therapeutic efficacy and patient compliance [5]
poly(lactic-co-glycolic acid) (PLGA) chain undergoes hydrolytic attack to the ester bond and the polymer totally degrades into LA and GA, which are endogenous compounds normally metabolized through the Krebs cycle [8,9]

Summary

Introduction

Synthetic and natural polymers normally degrade during their service-life, due to the exposure to different environmental conditions. The delivery of drugs from systems based on degradable biomaterials proved to offer important advantages, such as controlled drug release kinetics, which correlates with limited oscillation of drug concentration in blood, a reduction of number of drug administration, and an overall improvement of therapeutic efficacy and patient compliance [5]. In this context, a pivotal biomaterial is poly(lactic-co-glycolic acid) (PLGA), which is a thermoplastic, random, synthetic copolymer made up of lactic (LA) and glycolic (GA) acid units. PLGA can be processed in many different shapes and sizes; it is able to encapsulate, and subsequently release, molecules of any size [10]

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