Low molecular weight PLA: a suitable polymer for pulmonary administered microparticles?

Area of Science:

• Pharmaceutical Technology
• Materials Science
• Drug Delivery Systems

Background:

• Developing effective inhaled drug delivery systems is crucial for respiratory diseases.
• Microparticle formulations offer potential for controlled release of inhaled corticosteroids like beclomethasone dipropionate (BDP).

Purpose of the Study:

• To prepare and characterize beclomethasone dipropionate (BDP)-loaded microparticles for inhalatory application.
• To evaluate the influence of different polymers and molecular weights on microparticle properties and drug release.

Main Methods:

• Solvent evaporation/extraction method for microparticle preparation.
• Use of polylactic acid (PLA) and polylactic/glycolic acid (PLGA) as matrix polymers.
• Analysis of particle size, drug content, drug release kinetics, and surface morphology using HPLC and SEM.

Main Results:

• Microparticles with a mean diameter of 1-5 microns and drug content ≥23% were successfully prepared.
• PLA microparticles (MW 2000) exhibited prolonged and complete BDP release over 8 hours, while PLGA microparticles showed limited release (20% in 8 hours).
• In vitro studies showed microparticle structural integrity was maintained in diluted bronchial fluid for 36 hours, with minor degradation in other media.

Conclusions:

• PLA microparticles demonstrate promising characteristics for inhalatory delivery of beclomethasone dipropionate due to their favorable drug release profile and stability.
• The developed microparticle formulation exhibits good potential for effective respiratory drug delivery, warranting further investigation.