A rapid LC-MS/MS method for the simultaneous quantification of ivacaftor, lumacaftor, elexacaftor, tezacaftor, hexyl-methyl ivacaftor and ivacaftor carboxylate in human plasma.

Cystic fibrosis is one of the most common genetic diseases among caucasian population. This disease is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene encoding for the CFTR protein. Lumacaftor, elexacaftor, tezacaftor, and ivacaftor were currently used as the treatment to Cystic fibrosis. In this study, we describe a new method for the simultaneous quantification of four molecules: lumacaftor, elexacaftor, tezacaftor, and ivacaftor, alongside two metabolites of ivacaftor, specifically hexyl-methyl ivacaftor and ivacaftor carboxylate by liquid chromatography-tandem mass spectrometry. This method holds significant utility for therapeutic drug monitoring and the optimization of treatments related to CFTR modulators. Molecules were extracted from 100 µL of plasma by a simple method of protein precipitation using acetonitrile. Following extraction, chromatographic separation was carried out by reverse chromatography on a C18 analytical column, using a gradient elution of water (0.05 % formic acid, V/V) and acetonitrile (0.05 % formic acid, V/V). The run time was 7 minutes at a flow rate of 0.5 mL/min. After separation, molecules were detected by electrospray ionization on a Xevo TQD triple-quadrupole-mass-spectrometer (Waters®, Milford, USA). The calibration range were: 0.053-20.000 mg/L for elexacaftor, tezacaftor and lumacaftor, 0.075-14.000 mg/L for ivacaftor, and 0.024-6.500 mg/L for hexyl-methyl ivacaftor and ivacaftor carboxylate. The proposed method underwent throughout validation demonstrating satisfactory precision (inter- and intra-day coefficients of variation less than 14.3 %) and a good accuracy (inter- and intra-day bias ranging between -13.7 % and 14.7 %) for all the analytes. The presented method for the simultaneous quantification of CFTR modulators and their metabolites in human plasma has undergone rigorous validation process yielding good results including strong precision and accuracy for all analytes. This method has been effectively used in routine analytical analysis and clinical investigations within our laboratory.

The use of design of experiments to develop hot melt extrudates for extended release of diclofenac sodium.

The effect of formulation and processing parameters on processability and release from hot-melt extrusion (HME)-based matrices appears to be API and polymer dependent. Accordingly, the aim of this work was to design an extended-release formulation of diclofenac sodium by using HME technique and design of experiment (DoE). The extrudates were prepared using a vertical lab-scale single screw extruder. A D-optimal design with 16 formulations was employed to evaluate and model the effect of diclofenac sodium, ethyl cellulose and Natrosol L levels on the release profile. The percentage of drug release at 2, 4, 8 and 16 h were the dependent variables. The formulation factors that affect drug release were identified and satisfactorily modeled. The goodness of fit (R2) and goodness of prediction (Q2) parameters obtained for release responses were 0.913 and 0.682 at 2 h, 0.946 and 0.67 at 4 h, 0.942 and 0.658 at 8 h, and 0.892 and 0.673 at 16 h, respectively. The design space of optimal fractions of ethyl cellulose and Natrosol L at various drug levels was successfully constructed by response surface methodology. In conclusion, the DoE approach helped to identify and quantify formulation variables that affect the release of diclofenac sodium from HME-based formulation.