ABSTRACT
A simple, rapid and accurate ultra-high performance liquid chromatographic (UHPLC) method with a UV detection for the determination of the chemical purity and assay of bimatoprost (BT-1) was developed. The chromatographic separation was achieved with the use of an Acquity BEH C8, 150â¯×â¯2.1â¯mm, 1.7⯵m reversed phase analytical column. The mobile phase consisted of 0.01% H3PO4: acetonitrile (initial conditions 80 : 20, v/v) was passed through the column at the flow rate of 0.7â¯mL min-1. The separation was carried out in the gradient elution mode. The presented method allows to separate ten potential impurities of BT-1. The full validation according to the ICH Q2 (R1) guidelines was carried out for five of the potential impurities while limit tests were performed for four BT-1 related substances. The performed validation tests proved the suitability of the method for its intended purposes. An additional LC/MS method was utilized for the identification of the unknown impurities in bimatoprost as well as the degradation impurities generated during the forced degradation studies.
Subject(s)
Bimatoprost/analysis , Chemistry, Pharmaceutical/methods , Chromatography, High Pressure Liquid/methods , Chromatography, Reverse-Phase/methods , Drug Contamination , Drug Stability , Acetonitriles/chemistry , Limit of Detection , Linear Models , Mass Spectrometry , Quality Control , Reproducibility of ResultsABSTRACT
Theoretical and experimental evidence of a weak M(z)(R) dipole transition moment between the X(1)0g+ ground and (3)1u(5(3)P1) excited states in Cd2 is presented. Two independent attempts at recording an excitation spectrum of the (3)1u <-- X(1)0g+ transition using a laser beam crossed with a supersonic free-jet expansion beam are reported. The measurements were performed in a spectral range predicted as a result of both ab initio calculations of the electronic energy-state potentials involved in the transition and a simulation of the excitation spectrum. Unfortunately it was impossible to provide unambiguous experimental support for the calculated (3)1u-state potential, due to the very poor signal to noise ratio. However, the experimental results corroborate the very small values of the <(3)1u|M(z)|X(1)0g+> elements obtained in the calculations. This work provides as a reliable starting point for further analysis of the (3)1u-state characteristics.
