Spectrofluorimetric determination of macrolide antibiotics using eosin-g dye

A fully validated and simple spectrofluorimetric method was developed for the determination of azithromycin, clarithromycin, erythromycin ethylsuccinate, erythromycin stearate and roxithromycin in bulk powders and their dosage forms. The proposed method was based on ion pair formation of either one of the cited drugs with eosin-G dye in presence of Mcllvaine buffer and the resultant complex was extracted by chloroform. All variables affecting the intensity of the developed fluorescence products were studied and optimized. Straight line correlation was found over concentration ranges of 0.04–0.2, 0.4–6.4, 4.0–16, 1.6- 12, 0.4–4.0 microg ml-1 for azithromycin, clarithromycin, erythromycin ethylsuccinate, erythromycin stearate and roxithromycin respectively, with good correlation coefficients [0.9973 – 0.9994] The limits of detection and quantitation for this method ranged from 0.01 to 1.74 micro g ml-1 and from 0.04 to 5.79 micro g ml-1 respectively. The relative standard deviations were 1.54–2.15%. The proposed method was applied successfully for the determination of the cited drugs in different pharmaceutical dosage forms as tablets, capsules, granules as well as suspension without interference from common encountered additives with overall percentage recoveries ranged from 94.74 +/- 1.17 to 100.20 +/- 1.57. In addition no interference was observed due to other active ingredients as trimethoprim and sulfisoxazole acetyl. The results were compared favorably with those of reported method

Colorimetric determination of certain antifungals in pure forms and in their pharmaceutical formulations

An accurate and sensitive visible spectrophotometric method was developed and validated for the analysis of five antifungal drugs namely; clotrimazole, fluconazole, ketoconazole, miconazole nitrate and tolnaftate in pure as well as in their pharmaceutical dosage forms. This method was based on condensation of any of the cited drug with saturated solution of citric acid in anhydrous acetic anhydride in boiling water bath for about 20–30 min. The produced color was measured spectrophotometrically at 535 nm, after dilution with absolute ethanol. All variables affecting reaction conditions were optimized and the regression analysis of Beer's plots showed good correlation coefficients [0.9996 - 0.9999] for the previously mentioned drugs in a general concentration range of 0.8–7 microg ml-1 with overall limits of detection and quantitation in the following ranges: 0.039–0.26 microg ml-1 and 0.13–0.87 microg ml-1 , respectively. The proposed method has been applied successfully for the analysis of bulk drugs and their dosage forms such as topical powder and solution, oral and vaginal tablets, and topical creams. Overall percentage recoveries in the average range: 94.14–99.02% was obtained with considerable accuracy upon analysis of these dosage forms by the proposed method. No interference could be detected from betamethasone or dexamethosane, encountered excipients and additives. The obtained results have been compared with those obtained from reported and / or official method[s] and proper F- and t- values were observed; indicate no significance difference between the results of the proposed and reported methods. The good percentage recoveries and proper statistical data proved the efficiency of the proposed method for the analysis of the cited drugs in their commercial dosage forms with quite satisfactory precision

Simple spectrophotometric and spectrofluorimetric methods for determination of trimetazidine dihydrochloride

Two simple and sensitive spectrophotometric and spectrofluorimetric methods have been described for the determination of trimetazidine dihydrochloride in bulk and dosage forms. The first method depends on ion pair complexation between the cited drug with two dyes; tropaeloin 000 and methyl orange in aqueous medium. All variables affecting the formation of complex were studied and optimized. The coloured products of the drug with tropaeloin 000 and methyl orange were measured at 490 nm and 422 nm respectively, after extraction with chloroform. Beer's law was obeyed in the concentration ranges 4-20 [micro]g ml-1 and 2-12 [micro]g ml-1 for tropaeloin 000 and methyl orange respectively. The spectrofluorimetric method depends on the condensation of malonic acid and acetic anhydride under the catalytic effect of trimetazidine dihydrochloride. The condensation product gave two emission maxima measured at 452 nm [[lamda]ex 393 nm] and 470 nm [[lamda]ex 428 nm]. Variables affecting this condensation reaction were studied and optimized. At both maxima of emission good correlation was observed in the range 40-200 ng ml-1. The proposed methods were applied successfully for the determination of the cited drug in tablet dosage form without interference from common encountered additives. Percentage recoveries ranged from 98.9% to 99.7% in bulk and 96.9% to 98.3% in tablet dosage forms analysis