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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. 52-57

A gradient liquid chromatographic method which can separate isoniazid, pyrazinamide and rifampicin is described. A Hypersil C18, 5 mm, 250 mm x 4.6 mm internal diameter column was maintained at 40°C. The method was developed by systematic evaluation of the influence of the buffer concentration, column temperature and the mobile phase pH. The method proposed uses isocratic elution with potassium phosphate buffer (pH 6.0; 0.05 M) for 10 min, followed by linear gradient to potassium phosphate buffer (pH 6.0; 0.05 M)-methanol (40:60, v/v) in 5 min, isocratic elution at the same composition for a further 15 min and then linear gradient back to potassium phosphate buffer (pH 6.0; 0.05 M) in 5 min. The flow-rate was 1 ml/min and UV detection was at 254 nm. The method was validated and it has been used for routine analysis of tablets containing isoniazid, pyrazinamide and rifampicin. Analysis time is 35 minutes. (E & C Afr Jnl Pharm Sci: 2002 5(1): 8-14)