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.