Effect of nonionic surfactants [Dodecyl Maltoside and Polysorbate 20] on prevention of aggregation and conformational changes of recombinant human IFN beta_1b induced by light

Liquid protein formulations are prone to form aggregates. The effect of nonionic surfactants such as Polysorbate 20 [PS 20] and n-Dodecyl beta-D-maltoside [DDM] on the prevention of aggregation and conformational changes of recombinant human IFNbeta-1b [rhIFN beta_1b] was explored. Polysorbate has been used in formulations of protein pharmaceuticals. There have been concerns about using PS 20 due to its residual peroxide content which may negatively affect protein efficacy. n-Dodecyl beta-D-maltoside has been of interest and shown to be highly effective in prevention of aggregation. Fresh bulk of rhIFN beta_1b was formulated using DDM or different concentrations of PS 20. Formulations were exposed to light stress condition according to the ICH guideline of Q1b. The overall conformational integrity of individual samples was characterized by a combination of Circular dichroism [CD], Fluorescence spectroscopy and RP_HPLC techniques. The CD spectrum depicting the conformational integrity of rhIFN beta_1b showed 31.9% and 31.2% decreases in alpha-helix content of protein samples with 0.2% or 0.02% of PS20 compared to only18.2% of that containing 0.2% DDM. The RP-HPLC analysis also showed that the oxidized impurity in formulation containing DDM is less than those contain PS 20. Complementary analysis of the liquid formulations using IFR and UV methods also was in compliance with the data obtained by CD. Compared to PS 20, the sample of rhIFN beta_1b formulation with DDM was more resistant to the destruction effect of light. Results were in accordance with previous studies and could suggest DDM as a reliable anti-aggregation surfactant in biopharmaceutical formulations

Evaluation of thimerosal removal on immunogenicity of aluminum salts adjuvanted recombinant hepatitis b vaccine

Thimerosal, which is approximately 50% mercury by weight is a preservative widely used in vaccines since the 1930's. It meets the requirements for a preservative as set forth by Pharmacopeia challenge test and has been shown to be effective against a broad spectrum of pathogens. In July 1999, the Public Health Service agencies and vaccine manufacturers agreed that thimerosal should be reduced or eliminated in vaccines as a precautionary measure but, due to the lack of appropriate alternative, it is still extensively used in multiple dose formulations of vaccines such as hepatitis-B in developing countries. In this study the effect of the removal of thimerosal in two formulations of hepatitis B vaccines containing either aluminum hydroxide or aluminum phosphate were evaluated in Balb/c mice. These formulations were administered interperitoneally and the titer of antibody was determined by ELISA technique after 28 days. The geometric mean of antibody titer [GMT], seroconversion and seroprotection rates, ED50 and relative potency of different formulations were determined. The ED50 of thimerosal-free formulations were reduced by more than 35% in both preparations. In addition, GMT of antibody titer, seroconversion and seroprotection indicated significantly higher immunogenicity for thimerosal free formulations for both aluminum phosphate and hydroxide adjuvants

Optimization of enzymatic synthesis of ampicillin using cross-linked aggregates of penicillin G acylase

Penicillin G acylase from E. coli TA1 was immobilized by Cross-Linked Enzyme Aggregates [CLEA], a new method for immobilization. This biocatalyst and commercial immobilized penicillin G acylase [PGA-450] were used to study the effect of pH, temperature and substrate concentration on the synthesis of ampicillin from phenyl glycine methyl ester [PGME] and 6-aminopenicillanic acid [6-APA]. Compared with PGA-450, this immobilized enzyme showed a high synthesis activity. The optimum conditions for synthetic activity was at pH 6, 25°C and 2:6 [6-APA:PGME] substrate ratio

Bioburden of pharmacy prepared eucerin-urea ointments

Pharmaceutical products prepared in pharmacies have the potential of contamination with different microorganisms. This is in part due to the unhygienic environment and also lack of a suitable preservative system. In this study, microbial quality of Eucerin-Urea ointments prepared at different pharmacies in Tehran, at the point of sale and also after two weeks storage at room temperature was examined. All the samples examined immediately after purchase found to have total viable counts of lower than 102 cfu/g. The objectionable organisms e.g. Staphylococcus aureus, Candida albicans, Escherichia coli and Pseudomonas aeruginosa, however, were found in about 77%, 45.5%, 9.1% and 4.5% of the samples, respectively. After two weeks storage, contamination levels increased such that about 36.4% of samples were found to have the total viable counts greater than 102 cfu/g and Staphylococcus aureus, Candida albicans, Escherichia coli and Salmonella sp. were isolated from 86%, 59%, 18.2% and 9.1% of the samples. Depicted results show that significant microbial contamination of unhygienically produced or poorly formulated products in pharmacies can occur and because of lacking a suitable preservative system, the microbial population will increase during storage which may be harmful to the consumers or patients