Novel Aqueous solvent based method for protein based nanoparticles

The objective of the present study is to develop a novel method for the preparation of poly(D,L-lactide-co-glycolide)(PLGA) nanoparticles for protein/peptide delivery, and compare this method with traditional solvent evaporation methods for nanoparticle particle size and entrapment efficiency. The nanoparticles were prepared by three different methods namely: w/o/w emulsification-solvent evaporation method (ESE), nanoprecipitation method, and novel aqueous mixed micelle (MM) method. The prepared nanoparticles were evaluated as drug carrier systems using bovine serum albumin (BSA) as a model peptide. The physicochemical characteristics of the nanoparticles; morphology, particle size, zeta potential, and the effect of different parameters (method of preparation, time of stirring, drug concentration, and polymer concentration) on particle size and protein encapsulation efficiency percent (EE%) were studied. Severe aggregation of nanoparticles was noticed after freeze drying, especially for MM method. To reduce or completely prevent nanoparticle aggregation during freeze drying, three sugar cryoprotectants (glucose, trehalose, and mannitol) were evaluated. Results showed that all the preparation methods yielded greater than 90% EE of BSA into nanoparticles. Increasing the time of stirring during preparation decreased the particle size and was of a little effect on EE% in case of ESE and nanoprecipitation methods. On the other hand, the time of stirring has no effect on the particle size and EE% in case of MM method. Increasing the drug concentration and PLGA concentration was found to increase both particle size and EE%. Both glucose and trehalose protected nanoparticles from aggregation during freeze drying while mannitol had increased their aggregation. In conclusion, this study suggested the potential of preparing PLGA nanoparticles using aqueous solvent that can be used for loading peptide drugs.