Controlled release systems based on poly(lactic acid). An in vitro and in vivo study

Area of Science:

• Biomaterials Science
• Drug Delivery Systems
• Infectious Diseases

Background:

• Bone infections pose significant treatment challenges requiring localized, sustained antibiotic delivery.
• Biodegradable polymers offer promising platforms for controlled drug release, minimizing systemic exposure.
• Poly(lactic acid) is a well-established biocompatible and biodegradable polymer for medical applications.

Purpose of the Study:

• To formulate and evaluate a novel biodegradable delivery system based on poly(lactic acid) for sustained antibiotic release.
• To assess the in vitro and in vivo release kinetics of pefloxacin from poly(lactic acid) matrices.
• To determine if the released pefloxacin concentrations are effective against common bone infection pathogens.

Main Methods:

• Formulation of biodegradable discs using poly(D,L-lactic acid) with varying molecular weights (Mw = 2 x 10^3 and 2 x 10^4).
• Incorporation of pefloxacin at different drug loadings (2% and 10% w/w).
• In vitro and in vivo release studies to measure drug elution over time.
• Determination of Minimum Inhibitory Concentration (MIC) to assess antibacterial efficacy.

Main Results:

• Sustained in vitro release of pefloxacin from poly(D,L-lactic acid) (Mw = 2 x 10^3) lasted for 56 days.
• In vivo delivery of pefloxacin from the system lasted for 33 days.
• Release rates were governed by drug diffusion and polymer degradation, with degradation being predominant.
• Pefloxacin concentrations remained above the MIC for major bone infection bacteria.

Conclusions:

• Poly(lactic acid) serves as an effective biodegradable matrix for sustained antibiotic delivery systems.
• The developed system demonstrates potential for implantable applications in treating bone infections.
• Controlled release kinetics ensure therapeutic antibiotic levels at the infection site.