New Salting Out Stability-Indicating and Kinetic Thin Layer Chromatographic Method for Determination of Glimepiride and Metformin HCl Binary Mixture.

A simple, selective salting out and stability-indicating thin layer chromatographic (SOTLC) technique was developed for determination of two antidiabetic drugs; glimepiride and metformin HCl in pure and in tablets as a binary mixture. Separation was performed on silica gel 60 F254 plates using aqueous ammonium sulfate and acetonitrile (7:3, v/v) as a mobile phase. The Rf values were 0.26 ± 0.02 and 0.73 ± 0.02 for glimepiride and metformin HCl, respectively. The separated bands were scanned at λ 237 nm using CAMAG TLC scanner III. The proposed method focusing on study of all the factors that play important role in the mechanism of salting out process. The proposed method was validated according to ICH guidelines and complied with USP31-NF26 validation guidelines. The correlation coefficients of calibration curves were 0.996 and 0.997 for glimepiride and metformin HCl, respectively, in the concentration range of 60-1,400 ng/band for both drugs. The investigated drugs were also subjected to acidic, basic, oxidative and photo-degradation and kinetic study was carried out.

Salting-out thin-layer chromatography and computational analysis of some oral hypoglycemic drugs.

A quantitative structure-retention relationship study of some oral hypoglycemic drugs was carried out using a salting-out thin-layer chromatographic technique. Aqueous solution of ammonium sulfate and acetonitrile was used as a mobile phase. It was established that the applied mobile phase has different effects on retention of the studied oral antidiabetic drugs. The factors that affect the salting-out process were determined. In this study a good correlation between the structures of the investigated drugs with the retention data and molecular descriptors was established throughout computational analysis and using molecular operating environment software, focusing on octanol/water partition coefficient, molar refractivity, total hydrophobic surface area, hydrophobic volume, Van der Waals energy and solvation energy. Quantitative structure-retention relationship modeling for the separation of the investigated drugs was carried out, validated and evaluated.