Poly(DL-lactide-co-glycolide)/norethisterone microcapsules: an injectable biodegradable contraceptive.

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Pharmacology

Background:

• Biodegradable polymers are crucial for controlled drug delivery systems.
• Poly(DL-lactide-co-glycolide) (DL-PLGA) is a widely used biocompatible excipient.
• Norethisterone (NET) is a progestin used in various therapeutic applications.

Purpose of the Study:

• To investigate the impact of DL-PLGA composition and microcapsule size on NET release kinetics.
• To evaluate the in vivo biodegradation rates of DL-PLGA microcapsules.
• To identify an optimal NET microcapsule formulation for sustained release and complete biodegradation.

Main Methods:

• Solvent-evaporation microencapsulation was used to prepare NET-loaded DL-PLGA microcapsules.
• In vivo studies in baboons assessed NET release rates via radioimmunoassay (RIA).
• In vivo biodegradation was monitored in rats using radiolabeled DL-PLGA and combustion analysis.

Main Results:

• Increasing glycolide content in DL-PLGA accelerated NET release and copolymer biodegradation.
• Smaller microcapsule size resulted in faster NET release rates.
• A formulation was identified for 3-month NET release and complete biodegradation within 6 months.

Conclusions:

• DL-PLGA composition and microcapsule size are critical parameters for controlling drug release and biodegradation.
• The developed NET microcapsule formulation shows promise for clinical applications requiring long-term, controlled drug delivery.
• This research contributes to the advancement of biodegradable drug delivery systems for hormonal therapies.