Abstract

Background: Formulating protein drugs into delivery systems with high drug loading is particularly challenging. Another major hurdle for formulation processes generally used for protein drugs is their scalability. In this article, we present the application of spray drying to prepare polymeric microparticles of human recombinant IL-1 receptor antagonist (IL-1 ra).

Objective: The objective of this study was to formulate polymeric microparticles entrapping a therapeutic protein, human recombinant IL-1 ra using a spray drying process.

Methods: IL-1 ra was formulated using three polymers viz. gelatin, pectin, and sodium alginate by using a spray drying process to produce polymer entrapped drug microparticles. A single drug to polymer ratio was used in the three drug-polymer formulation combinations. The prepared microparticles were evaluated for morphology by scanning electron microscopy, average particle size by dynamic light scattering and drug entrapment efficiency by ELISA.

Results: Microparticles of three drug-polymer combinations were prepared using the Buchi B-90 spray dryer. The morphology of the three types of polymeric microparticles was found to be uniform by scanning electron microscopy. The average particle size for the three formulations ranged from 1 to 2.2 μ with a low standard deviation implying narrow particle size distribution. The drug loading efficiency ranged from 62 to 90 % W/W for the three formulations.

Conclusion: The presented study demonstrates the feasibility of using spray drying to prepare morphologically uniform polymer entrapped protein drug microparticles with high drug entrapment efficiency.

Keywords: Spray drying, IL-1 receptor antagonist, polymeric microparticles, gelatin, pectin, sodium alginate.

Graphical Abstract