Influences of process parameters on nanoparticle preparation performed by a double emulsion pressure homogenization technique

The preparation of nanoparticles (NP) as an improved colloidal carrier syst em for proteins was investigated. Bovine serum albumin (BSA) was used as mo del drug. Owing to the high solubility of the protein in water, the double emulsion technique has been chosen as one of the most appropriate method. I n order to both reaching submicron size as well as increasing the grade of monodispersity compared to previous preparation techniques, a microfluidize r as homogenization device was used. All experiments were performed using t wo biodegradable polymers, poly[D,L-lactic-co-glycolic acid] 50/50 (PLGA) a nd poly[epsilon-caprolactone] (PCL). The homogenization procedure has been optimized with regard to particle size and monodispersity by studying the i nfluence of the homogenization time as well as the amount of polymer and su rfactant in the external aqueous phase. The drug loading has been improved by varying the concentration of the protein in the inner aqueous phase. By increasing the protein concentration in the inner aqueous phase the polydis persity was slightly higher, while the particle size was not influenced sig nificantly. The BSA encapsulation efficiency decreased with higher protein concentration in the inner aqueous phase. All release profiles were charact erized by a initial burst effect, a higher release rate was obtained after 4 weeks for PLGA NP (60%) compared with PCL NP (47%). (C) 2000 Elsevier Sci ence B.V. All rights reserved.