Determination of cisapride in pharmaceutical preparations using derivative spectrophotometry.

Derivative spectrophotometric and high performance liquid chromatographic methods (HPLC) were described for the determination of cisapride in pharmaceutical preparations. Spectrophotometrically, cisapride was determined by measuring the 1D-values at 264, 300 nm and 2D-values at 276, 290 and 276-290 nm. Beer's Law was obeyed in the range 2-12 microg ml(-1). The HPLC method depends upon using micropack-Si-10 column at ambient temperature with a mobile phase consisting of methanol-concentrated ammonia (99.25:0.75) at a flow rate of 1 ml min(-1). Quantitation was achieved by UV detection at 272 nm using quinine as internal standard. Calibration curve was linear over the concentration range 2-10 microg ml(-1). Both derivative spectrophotometry and HPLC methods showed good linearity, precision and reproducibility. No interference was found from tablet or suspension matrices at the selected derivative wavelengths and chromatographic conditions. The proposed methods were successfully applied to the assay of commercial tablets and suspension. The procedures were rapid, simple and suitable for quality control applications.

Photodegradation kinetic study and stability-indicating assay of danazol using high-performance liquid chromatography.

A selective high-performance liquid chromatographic procedure for the stability-indicating determination of danazol in the presence of its photolytic degradation products is demonstrated. The photolysis was carried out in glass vials and quartz cell under UV light at 254 nm. Satisfactory results were obtained for the assay and recovery testing with RSD values less than 2%. Kinetic parameters evaluated comprise the order of reaction and the rate constants of the degradation of the danazol irradiated in glass vials or quartz cell.

Determination of astemizole by a spectrophotometric charge- transfer method.

Iodine-astemizole charge-transfer complex has been utilized for the assay of astemizole. The complex formed in the proposed method shows strong absorption at 360 nm with a corresponding molar absorptivity. epsilon of 3.26 x 10 L mol1 cm-1 and obeyance of Beer's law over the concentration range 2-12 pg/mi. When the proposed method was applied to commercial tablets labeled to contain 10 mg of active ingredient per tablet, the mean percentage found was 99.72 +/- 1.36. Analysis of variance, (ANO VA), and added recovery experiments indicated adequate precision and accuracy for the method.

AC-polarographic quantitation of tolmetin sodium.

Fundamental harmonic alternating current polarography has been described for the determination of tolmetin sodium and its capsules, (Tolectin-200 mg). The AC procedure was applied by superimposing 10 mV, rms, AC voltage on a DC ramp in the range -1200 to -1450 mV at a frequency of 50 Hz in acetate buffer of pH 5.0 containing 0.001% gelatin as a maxima suppressor. A three electrode assembly consisting of dropping mercury electrode (dme) and two Ag/AgCl/KCl (sat.) electrodes was employed. Mercury flow rate was 3 mg sec(-1) under a corrected head pressure of 80 cm. The electrode reaction was investigated by Kalousek K1 and K2 techniques which indicated the non-reversibility of the electrode process on the AC time scale. The percent result obtained by standard addition procedure was 101.4 +/- 2.0 for tolmetin sodium capsules.