Amoxicillin sodium-potassium clavulanate: evaluation of gamma radiation induced effects by liquid chromatography on both the individual drugs and their combination.

The effects of gamma irradiation on the stability of potassium clavulanate, amoxicillin sodium and their combination were investigated. A decrease in purity and increase in degradation products up to 30 days after the irradiation were evaluated by reversed phase HPLC. The comparison between unirradiated and irradiated amoxicillin sodium, performed within 24 h following the irradiation process, showed no significant increase in the pre-existing impurities and no evidence of newly induced degradation products.

Development and validation of a liquid chromatographic method for the determination of related substances in verapamil hydrochloride.

The development of a reversed-phase liquid chromatographic method for the determination of related substances in verapamil hydrochloride is described. The method is based on the use of a simple mobile phase on a specialty base-deactivated reversed-phase column. It enables the resolution of 13 related compounds from the parent drug and from each other.

Investigation of a new amoxicillin sodium impurity unstable in solution.

A new amoxicillin sodium impurity was detected by reversed-phase HPLC in commercial injectable preparations only when examined very soon after the drug was dissolved in the solvent vial (within about 10 min). The stability of this impurity was investigated by the degradation kinetic of its aqueous solutions. Ionspray mass spectrometry with flow-injection analysis and HPLC-MS methods were used to establish its nature.

The identification of related substances in triamcinolone acetonide by means of high-performance liquid chromatography with diode array detector and mass spectrometry.

A study of an HPLC method for the analysis of related substances in triamcinolone acetonide is described. Several systems of solvents and samples of different lots and preparative origins were examined and a rapid-scanning diode array UV detector (DAD) was particularly useful. With the proposed technique it was possible to identify 9 alpha-bromo desonide as a principal impurity, which was present in all examined samples of triamcinolone acetonide.

Quantitative analysis and purity evaluation of medroxyprogesterone acetate by HPLC.

A reversed-phase high-performance liquid chromatographic method was developed for the assay of medroxyprogesterone acetate and for the detection and determination of related steroids present as impurities in the drug. The method was compared with the normal-phase technique of the USP XX and was also applied to the analysis of tablets and injectable suspensions.