Simultaneous high-performance liquid chromatographic determination of atenolol and amlodipine in pharmaceutical-dosage form.

A simple, rapid and precise method is developed for the quantitative simultaneous determination of atenolol and amlodipine in a combined pharmaceutical-dosage form. The method is based on High Performance Liquid Chromatography (HPLC) on a reversed-phase column, shim-pack CLC, ODS (C18), 4.6 mmx25 cm & 0.5 mm, using a mobile phase of ammonium acetate buffer (the pH was adjusted to 4.5+/-0.05 with glacial acetic acid), acetonitrile and methanol (35::30:35 v/v). The buffer used in the mobile phase contains ammonium acetate in double-distilled water. The chromatographic conditions are- flow rate of 1.5 ml/min, column temperature at 40 degrees C and detector wavelength of 237 nm. Both the drugs were well resolved on the stationary phase and the retention times were around 1.5 minute for atenolol and 3.4 minute for amlodipine. The method was validated and shown to be linear for atenolol and amlodipine. The correlation coefficients for atenolol and amlodipine are 0.999963 and 0.999979, respectively. The relative standard deviations for six replicate measurements in two sets of each drug in the tablets is always less than 2% and mean % error of active recovery not more than +/-1.5%. The method was validated for precision and accuracy. The proposed method was successfully applied to the pharmaceutical dosage forms containing the above-mentioned drug combination without any interference by the excipients.

In vitro antimicrobial and cytotoxic activities of ferrocene derivative compounds.

The aim of the present study was to investigate the biocidal activity of four new ferrocene derivative based coordination complexes, [1,2,3-trithia-/3/-ferrocenophane, C1]; [disodium-1,1'-ferrocenedithiolate, C2]; [1,1'-(ferrocene-1,1'-diyl)-diethanol, C3]; [ferrocenyl(ethyl-phenyl)-methanol, C4]; against microbes (bacteria and fungi) and brine shrimp (Artemia salina Lech.) nauplii. C2 showed modest antibacterial activity at the concentration of 200 microg disc(-1) and gave its Minimum Inhibitory Concentration values at 32-64 microg mL(-1) against the tested bacteria. These complexes gave comparatively better antibacterial activity against the Gram-positives than the Gram-negatives. C3, C1 and C4 showed moderate antifungal activity at concentration of 200 microg disc(-1). Brine shrimp eggs were hatched in artificial sea water and exposed to the complexes. Median lethal concentration (LC50) values were calculated. Both complexes showed toxicity against brine shrimp but complex C3 explored its potent cytotoxicity having LC50 values at 6.031 microg mL(-1) (ppm).

Streptomyces bangladeshensis sp. nov., isolated from soil, which produces bis-(2-ethylhexyl)phthalate.

The taxonomic position of an actinomycete strain isolated from soil from Natore, Bangladesh, was examined by using a polyphasic approach. The strain, designated AAB-4(T), was assigned to the genus Streptomyces on the basis of chemical and morphological criteria. It formed Rectiflexibiles aerial hyphae that carried long chains of rounded spores. The 16S rRNA gene of strain AAB-4(T) was sequenced directly and then compared with those of previously studied streptomycetes following the generation of two phylogenetic trees by using maximum-likelihood and neighbour-joining algorithms. This confirmed the assignment of the novel strain to the genus Streptomyces. This strain showed a high level of 16S rRNA gene sequence similarity to Streptomyces thermoviolaceus, Streptomyces thermodiastaticus and Streptomyces longisporus, among others, but could be distinguished from them by phenotypic and physiological traits. This micro-organism produces bis-(2-ethylhexyl)phthalate, an antibacterial and antifungal agent. It is proposed that strain AAB-4(T) be classified as a novel species within the genus Streptomyces, as Streptomyces bangladeshensis sp. nov. (type strain, AAB-4(T)=LMG 22738(T)=NRRL B-24326(T)).