Accelerated polymer biodegradation of risperidone poly(D, L-lactide-co-glycolide) microspheres

Area of Science:

• Polymer Chemistry
• Materials Science
• Pharmaceutical Sciences

Background:

• Poly(D, L lactide-co-glycolide) (PLGA) is a widely used biodegradable polymer for drug delivery systems.
• Tertiary amines, like risperidone, are common in pharmaceuticals but can influence polymer degradation.
• Understanding drug-polymer interactions is crucial for designing stable and effective drug formulations.

Purpose of the Study:

• To investigate the influence of risperidone, a tertiary amine, on the hydrolytic degradation of PLGA microspheres.
• To characterize the impact of risperidone on PLGA microsphere properties and degradation kinetics.
• To provide insights for designing PLGA-based drug delivery systems containing tertiary amine drugs.

Main Methods:

• Fabrication of risperidone-loaded and blank PLGA microspheres at 65:35 and 85:15 lactide/glycolide ratios.
• Characterization using HPLC (drug loading), laser diffractometry (particle size), and SEM (surface morphology).
• Polymer degradation studies monitored by gel permeation chromatography (molecular weight) at 37°C in PBS.

Main Results:

• Risperidone presence enhanced hydrolytic degradation of both PLGA ratios, with faster degradation in 65:35 PLGA.
• Molecular weight reduction followed pseudo-first-order kinetics.
• Drug-loaded microspheres showed shriveled morphology; blank microspheres incubated with risperidone exhibited concentration-dependent surface porosity.

Conclusions:

• Risperidone accelerates the hydrolytic degradation of PLGA microspheres.
• The degradation is influenced by the drug's presence within the microenvironment and its concentration.
• Consideration of risperidone's effect is essential when designing PLGA dosage forms for tertiary amine drugs.