(39f) The Effects of the Operational Parameters on the Charactaristics of Protein Microparticles

The potential of peptid and protein therapeutics has been continuously increasing owing to the recent advances in biotechnology. Recently the demand on protein particles with qualified solid characteristics has increased e.g. because of their use for producing of protein containing pharmaceuticals. The optimum average particle size is often under 10 ìm because of the bioavailability of the macromolecules or their solubilization rate in solvents during the different drug formulation processes. Precipitation is a common method for recovery, concentration and purification of proteins. The precipitation can be carried out by different precipitating agent as inorganic salts, organic solvents and polyelectrolytes. Polyethylene glycol (PEG) is a favourable precipitant agent because it causes less denaturation of proteins at ambient temperatures. Most of the studies on protein precipitation by PEG have investigated the recovery, stability or purification efficiency of the processes. The aim of this study is to investigate the relation between the operational parameters of the salting-out precipitation and the morphological features of the protein particles (particle size and distribution, shape and agglomeration). For model material bovine serum albumin (BSA) was chosen which was salted out by different polyethylene glycols. According to the Weimarn laws supersaturation, solubility and operational time were chosen for the main operational parameters. In case of protein precipitation there is a solubility change depending on the initial protein concentration which was also investigated. The recovery and productivity rate of the precipitation process were compared to the optimum morphological characteristics of the protein microparticles.