Bhavin P. Marolia

Simultaneous Estimation of Ofloxacin, Clotrimazole, and Lignocaine Hydrochloride in Their Combined Ear-Drop Formulation by Two Spectrophotometric Methods

Two sensitive, accurate, and precise spectrophotometric methods have been developed and validated for the simultaneous estimation of ofloxacin (OFX), clotrimazole (CLZ), and lignocaine hydrochloride (LGN) in their combined dosage form (ear drops) without prior separation. The derivative ratio spectra method (method 1) includes the measurement of OFX and CLZ at zero-crossing points (ZCPs) of each other obtained from the ratio derivative spectra using standard LGN as a divisor, whereas the measurement of LGN at the ZCP of CLZ is obtained from the ratio derivative spectra using standard OFX as a divisor. The double divisor-ratio derivative method (method 2) includes the measurement of each drug at its amplitude in the double divisor-ratio spectra obtained using a standard mixture of the other two drugs as the divisor. Both methods were found to be linear (correlation coefficients of >0.996) over the ranges of 3-15, 10-50, and 20-100 μg/mL for OFX, CLZ, and LGN, respectively; precise (RSD of <2%); and accurate (recovery of >98%) for the estimation of each drug. The developed methods were successfully applied for the estimation of these drugs in a marketed ear-drop formulation. Excipients and other ingredients did not interfere with the estimation of these drugs. Both methods were statistically compared using the t-test.

Development and Validation of Stability-Indicating HPTLC Method for Estimation of Naratriptan Hydrochloride in Its Pharmaceutical Dosage Form and Its Content Uniformity Testing.

The present research project involves development and validation of a stability-indicating HPTLC method for the estimation of naratriptan-HCl in their pharmaceutical dosage forms and its content uniformity testing. Naratriptan-HCl was subjected to alkaline, acidic, oxidative, neutral, thermal (dry heat) and photo-degradation conditions. The chromatographic separation was carried out using a precoated silica gel G 60 F254 TLC plate as the stationary phase and dichloromethane-toluene-methanol-triethylamine (4 : 4 : 2 : 1, v/v/v/v) as the mobile phase. The spots of NRT-HCl and its degradation products were detected at 290 nm. The Rf value of NRT-HCl was found to be 0.60 ± 0.02. The linearity was obtained in the range of 100-500 ng/spot. The limit of detection and limit of quantitation were found to be 6.07 ng/spot and 18.41 ng/spot, respectively. The percentage recovery was found in the range of 98.87-99.55%. NRT-HCl was degraded under acidic, alkaline and oxidative conditions while stable under photolytic, neutral and dry heat conditions. The developed method was applied for estimation of naratriptan-HCl in marketed formulations and its content uniformity testing.

Degradation Kinetics Study of Alogliptin Benzoate in Alkaline Medium by Validated Stability-Indicating HPTLC Method.

A rapid, sensitive, and stability-indicating high-performance thin-layer chromatographic method was developed and validated to study degradation kinetics of Alogliptin benzoate (ALG) in an alkaline medium. ALG was degraded under acidic, alkaline, oxidative, and thermal stress conditions. The degraded samples were chromatographed on silica gel 60F254-TLC plates, developed using a quaternary-solvent system (chloroform-methanol-ethyl acetate-triethyl amine, 9+1+1+0.5, v/v/v/v), and scanned at 278 nm. The developed method was validated per International Conference on Harmonization guidelines using validation parameters such as specificity, linearity and range, precision, accuracy, LOD, and LOQ. The linearity range for ALG was 100-500 ng/band (correlation coefficient = 0.9997) with an average recovery of 99.47%. The LOD and LOQ for ALG were 9.8 and 32.7 ng/band, respectively. The developed method was successfully applied for the quantitative estimation of ALG in its synthetic mixture with common excipients. Degradation kinetics of ALG in an alkaline medium was studied by degrading it under three different temperatures and three different concentrations of alkali. Degradation of ALG in the alkaline medium was found to follow first-order kinetics. Contour plots have been generated to predict degradation rate constant, half-life, and shelf life of ALG in various combinations of temperature and concentration of alkali using Design Expert software.

Alkaline Degradation Kinetic Study of Thiocolchicoside by Stability Indicating High-Performance Thin-Layer Chromatographic Method

A stability indicating high-performance thin-layer chromatographic (HPTLC) method was developed using aluminum plates pre-coated with silica gel 60 F254 as the stationary phase and toluene: acetone: water (1.5:7.5:1.0, v/v/v) as the mobile phase with detection wavelength 277 nm. Thiocolchicoside was subjected to degradation in alkaline, acidic, oxidative, neutral, dry heat, and photolytic conditions. Linearity was observed in the concentration range 100–500 ng/spot with correlation coefficient (R2) 0.9961. The developed method was validated for specificity, accuracy, precision, limit of detection (LOD), and limit of quantification (LOQ) as per International Conference on Harmonisation (ICH) guidelines. The proposed method was successfully applied for the estimation of thiocolchicoside in pharmaceutical dosage forms and assay results were found to be in good agreement with the labeled claim of pharmaceutical dosage forms of thiocolchicoside. The proposed method was also applied for the degradation kinetic study of thiocolchicoside in 0.1 N, 0.5 N, and 1.0 N sodium hydroxide at different temperatures. The degradation of thiocolchicoside in all conditions was found to be first order and the highest degradation was found in 1.0 N NaOH at 60°C. The prediction of the degradation rate constant was also carried out at different temperatures and strengths of NaOH using Design Expert software-9 (trial version). The degradation products of thiocolchicoside formed in alkaline medium were isolated and characterized using infrared (IR), mass, and nuclear magnetic resonance (NMR) spectroscopy.