ABSTRACT
Three sensitive, accurate and rapid methods were suggested for the determination of the suggested drugs in pure form and in pharmaceutical preparation. The first method was based on the determination of sulpiride and tiapride by charge transfer complex formation with each of 2,3 dichloro-5,6-dicyano-p-benzoquinone [DDQ], 7,7,8,8-tetracyanoquinodimethane [TCNQ] and Iodine [12] and measuring the formed coloured complexes spectrophotometrically at 463 nm, 842 nm and 360 nm. Respectively for both drugs. All the experimental conditions affecting the reactions such as type of solvent, reagent concentrations, time, and temperature were studied and optimized. Beer's law was obeyed over the concentration range of 20-100 microgram/L for sulpiride with mean percentage accuracies of 100,00 +/- 0.06. 99.98 +/- 0.053 and 100.02 +/- 0.056 and 20 - 140 microgram/L for tiapride with aa reagents with mean percentage accuracies of 99.99 +/- 0.073, 99.97 +/- 0.051 and 100.04 +/- 0.076. The stoichiometry of the reaction was assessed by applying the molar ratio and continuous varation methods and found to be 1: 1. The second method was based on the determination of sulpiride and tiapride and veralipride by thin layer chromatography [TLC] method using developing system of acetonitrile: water: glacial acetic acid [10: 10: 1 v/v/v] followed by densitometric measurements of the spots of intact drugs at 290 nm. The determination was carried out on silica gel 60F254. The limits of Beer's law were 5-60, 10-60, and 5-60 microgram/spot for sulpiride, tiapride and veralipride, respectively. The third method was based on the determination of the drugs by high performance liquid chromatography [HPLC] methods using Luna CN 150x4.6 mm column. Buffer [0.1% heptanes sulphonic acid sodium salt + 0.1 ml of triethylamine + 1 ml of glacial acetic acid dissolved in 100 ml water]: methanol in ratio 35: 65 was used as mobile phase and the detection was at 244 nm with flow rate 1.5 ml/min using theophylline as an internal standard
ABSTRACT
Two chromatographic methods have been developed for the separation and determination of paracetamol [P] and tramadol [T]. The methods are applicable for the determination of both drugs either separately or in mixture. The first method is TLC scanning method in which the two drugs were separated on silica gel plate using methanol: water: glacial acetic acid 50: 50: 25 v/v as a developing system and spots were detected by UV scanning at 250nm for paracetamol and 275nm in case of tramadol. The calibration curve was found linear from 3 to 15 micro g/spot and from 14 to 80 micro g/spot in case of paracetamol and tramadol, respectively. The method was applied for the determination of both drugs in pure form with mean percent recoveries of 100.34 +/- l. 124 and 100.59 +/- 1.104 for paracetamol and tramadol, respectively. The method was successfully applied for the determination of both drugs in laboratory prepared mixture. The second method is an HPLC method in which the two drugs were separated on Hypersil MOS CIS [200x4.6mm] column using a mixture of 0.5M solution of potassium dihydrogen phosphate pH 3.3 and methanol 35:65 as a mobile phase. Detection was carried out by ultraviolet detection at 280nm. Linear relationship between the peak areas and concentrations were given over a range of 10-360 micro g/ml and from 20 to 360 micro g/ml for paracetamol and tramadol, respectively. The HPLC method was applied for the determination of both drugs in pure form with mean percent recoveries of 100.43 +/- 0.84 and 100.19 +/- 0.78 for paracetamol and tramadol, respectively. The method was successfully applied to the determination of both drugs in laboratory prepared mixture. The validity of TLC method and HPLC method was assessed applying the standard addition technique for the determination of paracetamol and tramadol in acetamadol tablets. Statistical comparison between the reference methods and the proposed methods showed no significant difference