Biodegradable polymers based on polylactide (PLA) and its co-polymers polylactide-co-glycolide (PLGA) were successfully spray dried with the Buchi Mini Spray Dryer B-290. Process parameters are found to prepare spherical particles with a smooth or structured surface.
A literature review demonstrates the feasibility to encapsulate different drugs in biodegradable microspheres for controlled drug delivery systems. Spray dried microparticles have a suitable size and shape for new application fields in pulmonary therapy, cancer treatment or medical devices.
Spray drying is a successfully employed method in pharmaceutical technology to prepare microspheres for controlled drug delivery systems.
Other common methods to produce microspheres are emulsification solvent evaporation, emulsification solvent extraction, or phase separation.
Comparing these methods, spray drying is a simple, rapid, reproducible and easy to scale-up technique. It is a one stage process, allowing mild temperature conditions. The spray drying technique is less dependent on the solubility of the drug (e.g. hydro solubility) and the polymer.
In the last two decades, polymers based on lactic acid and glycolic acid and their copolymers have attracted much interest as carriers in the preparation of different medical devices and drug delivery systems. These polymers meet the necessary criteria of excellent biocompatibility, biodegradability, and non-toxicity in humans – either in surgery or in drug delivery systems.
In pulmonary applications, biodegradable polymers are interesting for inhalation therapy, where the particles sizes have to be smaller than 5.8 microns in aerodynamic diameter. Spray drying has shown its potential use to achieve such small particle sizes.