Green synthesis of nanosilver particles by Aspergillus terreus HA1N and Penicillium expansum HA2N and its antifungal activity against mycotoxigenic fungi.

AIMS: The aim of this study was to synthesize silver nanoparticles (AgNPs) by an eco-friendly and low-cost method using the fungi Aspergillus terreus HA1N and Penicillium expansum HA2N as an alternative to chemical procedures mostly requiring drastic experimental conditions emitting toxic chemical byproducts. Also, this study has been extended to evaluate the effect of AgNPs on the growth of some mycotoxigenic fungi and ochratoxin A (OTA) produced by Aspergillus ochraceus. METHODS AND RESULTS: The AgNPs have been characterized by UV-Visible Spectrophotometer, Dynamic Light Scattering (DLS), Fourier Transform Infrared Spectroscopy (FTIR) and Transmission Electron Microscope (TEM). The TEM analysis has revealed that the size of AgNPs ranged between 14 and 25 nm in the case of P. expansum and 10-18 nm in the case of A. terreus. The antifungal activity of AgNP colloids has indicated that the highest inhibition zone was detected with AgNPs synthesized by A. terreus HA1N against all tested fungi. The highest inhibition zone was detected with Aspergillus niger at concentrations 3 and 6 µg of AgNP solution (7·56 ± 0·38 and 11·3 ± 1·8 mm, respectively) while, A. ochraceus showed the maximum inhibition zone (16·33 ± 0·96 mm) at the concentration 9 µg of AgNPs synthesized by A. terreus. The results have also indicated that the AgNPs synthesized by A. terreus and P. expansum at the concentration 220 µg/100 ml media gave the highest reduction of OTA, where the percentages of reduction were 58·87 and 52·18% respectively. CONCLUSIONS: The smallest size AgNPs synthesized by A. terreus HA1N are better in their antifungal activity against all tested mycotoxigenic fungi than the largest one synthesized by P. expansum HA2N. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first study focused on using AgNPs in control of OTA production.

Discrepancy among dissolution rates of commercial tables as a function of the dissolution method. Part 7: Aspirin.

The dissolution rate of fifteen batches of commercial aspirin tablets manufactured by five leading pharmaceutical companies was determined by closed and open dissolution systems. The most consistent results were those obtained by the USP method. Inter-batch as well as inter-brand variations were found to be more evidently detected and evaluated by adopting the USP and beaker methods, respectively. The bioavailability of these products was assessed in human subjects according to a cross-over design system. The following pharmacokinetic parameters for the drug were computed, viz., maximum excretion rate, elimination rate constant, half-life time, area under excretion rate versus time curve and total amount of drug excreted during 24 h following administration of a single oral dose. Based on the values of the correlation coefficient of the in vitro results obtained by different methods with the in vivo results, the beaker method appears to correlate best with the area under excretion rate versus time curve and total amount of drug excreted. Thus, determination of the dissolution rate of aspirin tablets by the beaker method can be considered as a reliable tool for predicting the in vivo performance of the preparation.