Drug interaction studies of gliquidone with fexofenadine, cetirizine, and levocetirizine

Simultaneous Determination of Chloroquine and Pyrimethamine with Cetirizine in an Active Form and Human Serum by RP-HPLC

A simple, accurate and precise RP-HPLC method was developed for the simultaneous determination of chloroquine, pyrimethamine and cetirizine hydrochloride concentrations in bulk drug and human serum. The assay was performed using a mobile phase of methanol: water (70:30) at pH of 2.8 ± 0.05 on the Purospher C-18 column with UV detection at 230 nm and rosuvastatin used as an internal standard. The retention times observed for chloroquine, pyrimethamine and cetirizine hydrochloride were 3.5, 2.5 and 5.5 minutes, respectively. The method was found to be specific for the assayed drugs showing a linear response in the concentration range of 1-100 μg mL-1 with coefficients of determination values of (r = 0.999). The method was developed and validated according to ICH guidelines. The method was used to monitor the serum samples and was found to be sensitive for therapeutic purposes, showing the potential to be a useful tool for routine analysis in laboratories.

In vitro drug interaction of levocetirizine and diclofenac: Theoretical and spectroscopic studies

Levocetirizine dihydrochloride is known to interact with some anti-inflammatory drugs. We report here a comprehensive integrated theoretical and experimental study for the in vitro drug interaction between levocetirizine dihydrochloride (LEV) and diclofenac sodium (DIC). The interaction of the two drugs was confirmed by the molecular ion peak obtained from the mass spectrum of the product. Moreover, FTIR and ¹HNMR spectra of the individual drugs and their interaction product were inspected to allocate the possible sites of interaction. In addition, quantum mechanical DFT calculations were performed to search for the interaction sites and to verify the types of interactions deduced from the spectroscopic studies such as charge-transfer and non-bonding π-π interactions. It was found that the studied drugs interact with each other in aqueous solution via four types of interactions, namely, ion-pair formation, three weak hydrogen bonds, non-bonding π-π interactions and charge-transfer from DIC to LEV.