Abstract. Chemical coupling of polyethylene glycol (PEG) to proteins or particles (PEGylation), prolongs their circulation half-life by greater than 50-fold, reduces their immunogenicity, and also promotes their accumulation in tumors due to enhanced permeability and retention effect. Herein, phase separation method was used to prepare bovine serum albumin (BSA) nanoparticles. PEGylation of BSA nanoparticles was performed by SPA activated mPEG through their free amino groups. Effect of process variables on PEGylation efficiency of BSA nanoparticles was investigated and optimized through response surface methodology with the amount of free amino groups as response. Optimum conditions was found to be 32.5 g/l of PEG concentration, PEG-nanoparticle incubation time of 10 min, incubation temperature of 27°C, and pH of 7 for 5 mg of BSA nanoparticles in 1 mL phosphate buffer. Analysis of data showed that PEG concentration had the most noticeable effect on the amount of PEGylated amino groups, but pH had the least. Mean diameter and zeta potential of PEGylated nanoparticles under these conditions were 217 nm and −14 mV, respectively. In conclusion, PEGylated nanoparticles demonstrated reduction of the negative surface charge compared to the non modified particles with the zeta potential of −31.7 mV. Drug release from PEGylated nanoparticles was almost slower than non-PEGylated ones, probably due to existence of a PEG layer around PEGylated particles which makes an extra resistance in opposition to drug diffusion.

Curcumin was loaded into different polysaccharide nanoparticles chitosan, alginate and starch, using the desolvation method. Curcumin-loaded nanoparticles exhibited enhanced solubility in aqueous solutions comparing with free curcumin. Effects of formulation parameters such as curcumin concentration and different volumes of ethanolic solution were affected the particle size and loading efficiency. Under optimum conditions, curcumin-loaded chitosan, starch and alginate nanoparticles with mean particles sizes of 66.3, 61.1 and 78.8nm, and maximum loading efficiencies of 11.9%, 14.3% and 13.35% were achieved, respectively. Additionally, the minimum inhibitory concentration for chitosan, starch and alginate nanoparticles against the microorganism, Streptococcus mutans, were 0.114, 0.204 and 0.204mg/mL, respectively. Curcumin was observed to release from nanoparticles under physiological pH over a period of 96h. The effect of curcumin-loaded nanoparticles on S. mutans biofilms was assessed on dental models. According to the results, curcumin-loaded chitosan nanoparticles hold promises for being used in dental decay fighting products.

Abstract. Over the past few decades, there has been considerable interest in developing protein nanoparticles as drug delivery devices. The underlying rationale is their exceptional characteristics, namely biodegradability and nonantigenicity. Herein, phase separation method was used to prepare 5-fluorouracil-loaded bovine serum albumin (BSA) nanoparticles. Drug release was tracked by continuous flow dialysis technique. Effect of process variables on loading efficiency of 5-fluorouracil was investigated and optimized through Taguchi's M16 design with the amount of entrapped drug as response. Optimum condition was found to be 2 mg/mL of 5-fluorouracil, 3.7 mL of added ethanol, 176 µL of glutaraldehyde, drug-protein incubation time of 30 min, and pH of 8.4 for 200 mg of BSA in 2 mL drug solution. pH had the most noticeable effect on the amount of entrapped drug, but glutaraldehyde had the least. Mean diameter and zeta potential of fabricated nanoparticles under these conditions were 210 nm and −31.7 mV, respectively. Drug-loaded BSA nanoparticles suspension maintained constant release of drug for 20 h under experimental conditions, so this colloidal drug carrier is capable of releasing drug in a sustained manner.

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