Quantification of three macrolide antibiotics in pharmaceutical lots by HPLC: Development, validation and application to a simultaneous separation

A new validated high performance liquid chromatographic (HPLC) method with rapid analysis time and high efficiency, for the analysis of erythromycin, azithromycin and spiramycin, under isocratic conditions with ODB RP18 as a stationary phase is described. Using an eluent composed of acetonitrile –2-methyl-2-propanol –hydrogenphosphate buffer, pH 6.5, with 1.5% triethylamine (33:7: up to 100, v/v/v), delivered at a flow-rate of 1.0 mL min-1. Ultra Violet (UV) detection is performed at 210 nm. The selectivity is satisfactory enough and no problematic interfering peaks are observed. The procedure is quantitatively characterized and repeatability, linearity, detection and quantification limits are very satisfactory. The method is applied successfully for the assay of the studied drugs in pharmaceutical dosage forms as tablets and powder for oral suspension. Recovery experiments revealed recovery of 97.13–100.28%

Bioavailability of different artemisinin tablet formulations in rabbit plasma - correlation with results obtained by an in vitro dissolution method

The demonstration of a good overall correlation with in vivo data is the ultimate proof of qualification for any dissolution-rate test. For artemisinin, a very hydrophobic compound at a high content in oral solid dosage forms, all official dissolution apparatus were estimated unsuitable. A modified two phase partition-dissolution method was applied to solve this problem. This study reports on the bioavalability of three different formulations of artemisinin tablets in rabbit plasma. Artemisinin concentrations in plasma were determined by liquid chromatography. A linear correlation between results obtained by the partition-dissolution method described and the obtained in vivo data confirmed the validity of the dissolution method. (C) 1997 Elsevier Science B.V

Minimal number of chromatographic test parameters for the characterisation of reversed-phase liquid chromatographic stationary phases

This paper focuses on the classification or differentiation of RP-HPLC columns based on measured chromatographic properties. A chemometric study has been conducted on a published data set consisting of 85 RP-HPLC columns and on a data set consisting of 47 self-tested columns. Principal component analysis enables determination of the number of parameters necessary for a rational differentiation. The results show that reducing the number of parameters for such differentiation still allows classification of the columns just as a higher number did. It is shown that three test parameters produce a classification similar to that obtained with five parameters</p

Steroidal Indoxyls: Evaluation of Pka Values and Anti-inflammatory Activity

Three steroidal indoxyls, 3-oxo-16,17-seco-16-nor-1,4-androstadien-15-(7\'-methoxy-2-indoxyliden)17-oic acid, 1-(2\'-indoxyliden)-2-nor-1,2-secocholestan-3-oic acid and 1-(5\'- chloro-2-indoxyliden)-2-nor-1,2-secocholestan-3-oic acid were synthesized and screened for anti-inflammatory activity. Their pKa values were also determined using a solubility method. The first compound, 3-oxo-16,17-seco-16-nor-1,4-androstadien-15-(7\'-methoxy-2-indoxyliden) 17-oic acid, had an ED50 value of 15.3 mg/kg and a pKa of 7.09. The cholestane derivative, 1-(2\'-indoxyliden)-2-nor-1,2-secocholestan-3-oic acid, and its chloro analogue 1-(5\'-chloro-2-indoxyliden)-2-nor-1,2-secocholestan-3-oic acid had ED50 values of 16.2 and 22.8 mg/kg, while their pKa values were 6.56 and 7.07, respectively, suggesting that these compounds are relatively weak acids. Keywords: Steroidal indoxyls, pKa values, anti-inflammatory The East and Central African Journal of Pharmaceutical Sciences Vol. 9 (2) 2006: pp. 52-5