The present study was initiated to understand the effect of PLGA concentration, PVA concentration, internal-external phase ratio, homogenization speed, and homogenization time on mean particle size, zeta potential, and percentage drug encapsulation using fractional factorial design. Using PLGA (50-50) as the carrier, hyaluronidase loaded PLGA nanoparticles were prepared using double emulsion solvent evaporation technique. The particle size was analyzed by dynamic light scattering technique and protein content by Lowry method. The study showed that homogenization speed as an independent variable had maximum effect on particle size and zeta potential. Internal-external phase volume ratio had maximum effect on drug encapsulation. Mean particle size also had high dependency on the combined effect of PVA concentration and phase volume ratio. Using fractional factorial design particle size of <400 nm, zeta potential of <−30 mV, and percentage encapsulation of 15–18% were achieved.

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Histidine phosphorylation plays a key role in prokaryotic signaling and accounts for approximately 6% of the protein phosphorylation events in eukaryotics. Phosphohistidines generally act as intermediates in the transfer of phosphate groups from donor to acceptor molecules. Examples include the bacterial phosphoenolpyruvate:sugar phosphotransferase system (PTS) and the histidine kinases found in two-component signal transduction pathways. The latter are utilized by bacteria and plants to sense and adapt to changing environmental conditions. Despite the importance of histidine phosphorylation in two-component signaling systems, relatively few proteins have so far been identified as containing phosphorylated histidine residues. This is largely due to the instability of phosphohistidines, which, unlike the phosphoesters formed by serine, threonine, and tyrosine, are labile and susceptible to acid hydrolysis. Nevertheless, it is possible to preserve and identify phosphorylated histidine residues in target proteins using appropriate sample preparation, affinity purification, and mass spectrometric techniques. This chapter provides a brief overview of such techniques, describes their use in confirming histidine phosphorylation of a known PTS protein (HPr), and suggests how this approach might be adapted for large-scale identification of histidinephosphorylated proteins in two-component systems.[27]identification of histidine phosphorylations 549

Cyclodextrins (CDs) are carrier molecules produced by cyclization of α-1,4-glucans by Cyclodextrin Glycosyl Transferase (CGTase). These torus shaped molecules have hydrophobic cavity and hydrophilic shell making them useful in pharmaceutical, food, textile, pesticide and cosmetic industries. In this study, culture conditions for the production of CGTase by organism belonging to Arthrobacter genus obtained from a paddy field soil were optimized by single parameter mode. Soluble starch, yeast extract and magnesium sulphate played an important role in CGTase production. Percentage increase in CGTase yield under optimized conditions was 396.77%. The enzyme precipitated by 60% ammonium sulphate was purified using DEAE-sepharose. The molecular weight of the purified protein as determined by SDS-PAGE was 75 kDa. Purified CGTase was thermostable and stable over a wide pH range. Dissolution studies on β -cyclodextrin-Irbesartan complex revealed that β -CDs formed were useful in preparing immediate release oral dosage forms.