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Two simple, accurate, precise, reproducible and economical UV spectroscopic methods (A &  B) for simultaneous estimation of Ciprofloxacin and Tinidazole in tablet dosage form have been developed. Method A employs solving of simultaneous equations based on the measurement of absorbance at two wavelengths, 271nm and 318nm which are the ?max values of Ciprofloxacin and Tinidazole respectively in phosphate buffer (pH 6.8). Method B is based on the principle of  Q-Analysis where in the absorbance was measured at 292nm (iso-absorptive point) and 271nm (?max of Ciprofloxacin)in phosphate buffer (pH 6.8). Ciprofloxacin and Tinidazole  shows linearity at all the selected wave-lengths and  obeys Beer’s law in the concentration range of 10-35µg/mL and 10-80µg/mL respectively.  Recovery studies for Ciprofloxacin and Tinidazole were performed and the percentage recovery for both the drugs was obtained in the range of 98.1-99.7% (Method A) and 98.0-100.4% (Method B) confirming the accuracy of the proposed method. Both the methods showed good reproducibility and recovery with %RSD less than 2. Statistical validation of the data shows that the proposed methods can be successfully applied for the routine analysis of drugs in commercial tablets.DOI: http://dx.doi.org/10.3329/icpj.v1i10.11849 International Current Pharmaceutical Journal 2012, 1(10): 317-321

A simple, robust stability indicating RP-HPLC method was developed for simultaneous quantification of serdexmethyl phenidate and dexmethyl phenidate in a fixed capsule dosage form. This is the first method to be reported for simultaneous estimation and quantification of degradation products produced from forced stressing of the dosage form as per ICH guidelines. The chromatographic separation was attained on Waters X-terra C18 column using a mixture of trifluoro acetic acid and acetonitrile (70:30 v/v) as mobile phase with a flow rate of 1 mL, monitored at 265 nm over a run time of 10 min. Serdexmethyl phenidate and dexmethyl phenidate were eluted with retention times of 2.71 min and 7.33 min, respectively. The method displayed linear responses in the range of 4.2–63 μg/mL (0.9994) for serdexmethyl phenidate and 0.9 to 3.5 μg/mL (0.9998) for dexmethyl phenidate, respectively. The percentage recoveries of the two drugs were found within the acceptable limits. Forced degradation was conducted and showed considerable degradation in various stress conditions. It also confirms the specificity of the method as no interference peaks were observed concerning for to stress products. This method can be routinely used in quality control labs for simultaneous determination of respective drugs in marketed dosage form.

The spectrophotometric multi-component analysis involves spectrum recording and mathematical equations. However, spectral interference poses a major limitation when mixture samples are encountered. To overcome this derivative spectrophotometry (DS) has been introduced for the resolution of overlapping peaks. In this review modified methods like derivative quotient spectra, double divisor ratio spectra derivative method, double divisor means centering of ratio spectra method, derivative subtraction coupled with the constant multiplication method (DS-CM), amplitude subtraction (AS), modified amplitude subtraction (MAS), amplitude factor method (P-Factor), amplitude modulation method (AM), amplitude summation method (A-Sum), simultaneous derivative ratio spectrophotometry (S1DD), derivative compensation ratio via regression equation, differential dual wavelength (D1 DWL), differential derivative ratio (D1DR), successive derivative subtraction method (SDS) and derivative transformation (DT) of derivative spectrophotometry theories and applications are reviewed. These methods were applied to solve different complex pharmaceuticals mixtures. These developed methods were simple and cost-effective.

Raloxifene hydrochloride is a new anti-osteoporotic agent, effective in the treatment of breast cancer. A stability-indicating high-performance liquid chromatographic method was developed and validated for the determination of Raloxifene Hydrochloride in tablet dosage forms. Reversed-phase chromatography was performed on Shimadzu M odel LC-20AD Prominence with SPD M 20A Diode array detector using a Phenomenex Lichrosphere 100 C-18 (250 mm × 4.6 mm i.d., 5 µm particle size) column with sodium acetate: methanol (40:60, V/V) as mobile phase with a flow rate of 1 ml/min. UV detection was performed at 287 nm. Linearity was observed in the concentration range of 1.0-250 μg/mL with regression equation y = 95604 x-26215 with correlation coefficient of 0.9999. The LOD and LOQ were found to be 0.267 μg/mL and 0.813 μg/mL respectively. The percentage relative standard deviation in precision and accuracy studies was found to be less than 2%. Raloxifene hydrochloride was subjected to stress conditions of degradation in aqueous solutions including acidic, alkaline, oxidation and photolysis. It was found that the drug is highly resistant towards all degradations as the decomposition was less than 3.5%. The developed method was validated with regard to linearity, accuracy, precision, selectivity and robustness and the method was found to be precise, accurate, linear and specific.