K. Vinutha

A simple, precise, and accurate UV spectrophotometric method was developed and validated for the simultaneous estimation of Lornoxicam and Thiocolchicoside in bulk and pharmaceutical formulations. The method employs methanol as solvent, and absorbance was measured at the respective wavelengths where both drugs showed maximum absorbance with minimal interference. Calibration curves were linear within the concentration ranges of 4–20 µg/mL for Lornoxicam and 5–25 µg/mL for Thiocolchicoside, with correlation coefficients (R²) of 0.9992 and 0.9995, respectively. Validation was carried out according to ICH Q2(R1) guidelines, including parameters such as linearity, accuracy, precision, LOD, LOQ, robustness, and ruggedness. Recovery studies at 50%, 100%, and 150% levels showed recoveries between 98.7–100.1%, indicating high accuracy. The proposed method is suitable for routine quality control of combined dosage forms of Lornoxicam and Thiocolchicoside.

We developed a straightforward, precise method for the simultaneous estimation of Ivacaftor, Elexacaftor and Tezacaftor in both bulk and tablet dosage forms. The chromatography analysis was performed using a Discovery C18 column measuring 150 x 4.6 mm with a 5µm particle size. The mobile phase, composed of Acetonitrile: Methanol: 0.1% OPA (10:35:55 v/v) was pumped at a flow rate of 0.9 ml/min, with the temperature maintained at 28°C. The optimized wavelength for detecting 3 drugs was set at 278.0 nm. Retention times were measured at 2.537 min, 2.089 min, and 3.090 min, respectively. The method precision showed low %RSD values, with 0.4 for Ivacaftor, 0.3 for Elexacaftor and 0.4 for Tezacaftor. Recovery percentages were determined as 99.79% for Ivacaftor, 99.72% for Elexacaftor and 100.05% for Tezacaftor. Furthermore, the LOD and LOQ values derived from the regression equations for  Ivacaftor, Elexacaftor and Tezacaftor i.e  y = 22674x + 2799.3, y = 21285x + 4513.2 and y = 21548x + 869.63  were found to be 0.06 ppm and 0.22 ppm, 0.18 ppm and 0.19 ppm , 0.07 ppm and 0.57 ppm  respectively. With reduced retention times, this method offers simplicity and cost-effectiveness, making it suitable for routine quality control testing.

A Stability indicating isocratic liquid chromatographic method with UV detection at 255 nm is described for simultaneous determination of sofosbuvir and velpatasvir  in its bulk and tablet dosage form. Chromatographic separation of two drugs was achieved on a YMC column (4.6×15mm,5 ) using a mobile phase consisting of a binary mixture of acetonitrile and 0.025M KH2PO4  adjusted to pH3..0 with orthophosphoric acid in ratio 50:50. The developed Liquid Chromatographic method offers symmetric peak shape, good resolution and reasonable retention time for both drugs. Linearity, accuracy and precision were found to be acceptable over the concentration range of 50-250 µg/ml for velpatasvir and 200-1000µg/ml for sofosbuvir and R2 found to be 0.999. Accuracy was measured via recovery studies and found to be acceptable, and the percentage recoveries were found in the range of 97-103%.Method precision results obtained are 0.1%RSD for sofosbuvir and 0.8%RSD for velpatasvir. Forced degradation studies were also conducted, and the drugs were subjected to various stress conditions such as acid hydrolysis, base hydrolysis, oxidative, photolytic and thermal degradation. The proposed method was successfully validated and applied for the quantitative estimation of these drugs in both bulk and tablet dosage forms. The LC method can be used for the quality control of formulated products containing sofosbuvir and velpatasvir.