Simultaneous determination of olanzapine and fluoxetine hydrochloride in capsules by spectrophotometry, TLC-spectrodensitometry and HPLC

This paper describes sensitive, accurate and precise spectrophotometric, TLC-spectrodensitometric and high performance liquid chromatographic [HPLC] methods for simultaneous determination of olanzapine and fluoxetine HCl. Two spectrophotometric methods were developed, namely; first derivative [D[1]] and derivative ratio [DD[1]] methods. The TLC method employed aluminum TLC plates precoated with silica gel GF[254] as the stationary phase and methanol: toluene:ammonia [7:3:0.1, by volume] as the mobile phase, where the chromatogram was scanned at 235 nm. The developed HPLC method used a reversed phase C18 column with isocratic elution. The mobile phase composed of phosphate buffer pH 4.0:acetonitrile:triethylamine [53:47:0.03, by volume] at flow rate of 1.0 mL min[-1]. Quantitation was achieved with UV detection at 235 nm. The methods were validated according to the International Conference on Harmonization [ICH] guidelines. The selectivity of the proposed methods was tested using laboratory-prepared mixtures. The developed methods were successfully applied for the determination of olanzapine and fluoxetine HCl in bulk powder and combined capsule dosage form

Simultaneous determination of bisoprolol Fumarate and hydrochlorothiazide in tablets by derivative spectrophotometry and densitometry

Derivative spectrophotometry [second and fourth] and densitometry were used to determine bisoprolol fumarate [I] and hydrochlorothiazide [II] simultaneously in combined pharmaceutical dosage form. Using second derivative spectrophotometry, the amplitudes in the second derivative spectra at 272.6nm and 284.8nm were selected for simultaneous determination of [I] and [II], respectively, in the mixture. Where, the HZ concentration was calculated from the amplitude at 284.8 nm [where BSF showed no absorbance] and BSF concentration was calculated from the amplitude at 272.6 nm after subtraction of the amplitude due to HZ. While, applying fourth-derivative spectrophotometry technique, the peak amplitudes at 289.8 nm and 272.8 nm were selected to determine [I] and [II], respectively. The calibration graphs were linear in the range of 30-280 microg/ml for [I] and 3-24 microg/ml for [II] in both methods. Furthermore, a densitometric procedure with ultraviolet detection at 223nm was applied using chloroform: ethanol: Glacial acetic acid [7:3:2 by volume] as a developing system. The plot of peak area of [I] and [II] to the respective concentrations of each drug was found to be linear in the range of 2.5-30micro g/spot and 1-7 micro g/spot, respectively. The suggested methods were used to determine both compounds in synthetic mixtures and in commerical tablets. The validity of the proposed methods was further assessed by applying standard addition technique. The obtained results were statistically compared with compandial HPLC method, showing no significant difference with respect to accuracy and precision