Among the microorganisms employed in the study, Aspergillus niger (GUFCC5443), Escherichia coli (ATCC9637), Streptomyces halstedii (CKM-2), Pseudomonas putida (NCIB9494), Cunninghamella elegans (NCIM689) and Sphingomonas paucimobilis (NCTC11030) were capable for the enantioselective conversion of racemic Carvedilol. Immobilization technique enhanced the enantioselectivity of microorganisms and thus increased the enantiomeric purity of the drug. Excellent enantiomeric ratios (E) were found in reactions catalyzed by immobilized A. niger and E. coli with values 174.44 and 104.26, respectively. Triacylglycerol lipase from Aspergillus niger was also employed in this study as a biocatalyst which resulted in the product with 83.35% enantiomeric excess (ee) and E of 11.34 while the enzyme on immobilization has yielded 99.08% ee and 216.39 E. The conversion yield (C%) of the drug by free-enzyme was 57.42%, which was enhanced by immobilization to 90.51%. Hence, our results suggest that immobilized triacylglycerol lipase from A. niger (Lipase AP6) could be an efficient biocatalyst for the enantioselective resolution of racemic Carvedilol to (S)-(−)-Carvedilol with high enantiomeric purity followed by immobilized cultures of A. niger and E. coli.

A simple chiral HPLC method was developed and validated for quantification of S(-)-Carvedilol in Active Pharmaceutical Ingredient (API) and marketed tablet formulation of racemic Carvedilol. Chiral resolution of enantiomers of Carvedilol was achieved on Phenomenex Lux-cellulose-4 (250 mm × 4.6 mm; 5 µ particle size) chiral column by using a mobile phase, Isopropanol and n-Heptane (60:40 v/v), at a flow rate of 1.0 ml/min and by employing UV detection at 254 nm wavelength. The method was validated according to the ICH guidelines and was proved to be specific, linear, precise and accurate for the analysis of S(-)-Carvedilol.

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The present study involves the enantioselective resolution of racemic Felodipine by using free and immobilized forms of microbial cultures as well as an enzyme (Lipase AP6). Among the microbial cultures employed in the present study, Aspergillus niger, Sphingomonas paucimobilis, Cunninghamella elegans, Escherichia coli, Pseudomonas putida and Cunninghamella blakesleeana were found to possess capability of enantioselective resolution of racemic Felodipine. The enantiomeric excess (ee%) of Felodipine after reaction catalyzed by whole-cell A. niger and S. paucimobilis was found as 81.59 and 71.67%, respectively. Immobilization enhanced the enantioselectivity (enantiomeric ratio (E)) of the biocatalysts and hence this led to enhanced enantiomeric purity of the drug. The ee% values were found to be enhanced in reactions catalyzed by A. niger and S. paucimobilis cultures after immobilization as 98.27 and 93.56%, respectively. Enantiomeric ratio (E) of the reactions catalyzed by all the biocatalysts has been improved after immobilization. E value of the reaction catalyzed by immobilized A. niger was found to be excellent (E > 100) and hence the drug showed high enantiomeric purity. In lipase AP6 catalyzed study, the enantioselectivity was enhanced after immobilization with excellent E value, which led to enhanced enantiomeric purity of the drug (99.21% ee%).

Background. Dengue is a mosquito-borne disease and its occurrence is a worldwide problem. The health seekers may turn to the Internet based data for possible complications and various therapeutic approaches for the treatment. Therefore, our objective is to identify and characterize the seasonal transition of dengue fever using Google Trends. Methods. This was a cross-sectional study of dengue fever internet searches between 2004 and 2017. The Google was indexed the aggregated web data and ranked based on the search volume with respect to time. The countries selected for the study include India, Brazil, Paraguay, Philippines and Singapore based on the maximum number of cases across world. The selected regions were further classified in to seasonal time points and the relative search volume ranks were categorized to two season variables. Mann–Whitney U test was applied to identify the statistical significance. Results. The summer to monsoon transitions were showed highest number cases beginning from 2004 in the selected regions. Furthermore, dengue searches were peaked in both the seasons of summer and monsoon in selected regions. The analyses of data further revealed that 16.2 % of variation in dengue trends is associated with the time between 2004 and 2017.