Valbenazine isomers and enantiomer determination by chiral normal phase liquid chromatography.

A novel, simple, specific, rapid, enantioselective normal phase chiral high-performance liquid chromatographic method with amylose-based Chiral Pak IG-3(250 × 4.6 mM) 3.0 µM column was developed and validated for separation and quantification of isomers and enantiomer of Valbenazine. The mobile phase composed of n-Heptane, isopropyl alcohol, dichloromethane, ethanol, and diethylamine in the ratio of 70:10:15:5:0.1 (V/V/V/VV) with a gradient flow rate was applied. The injection volume was 10 µl, and detection was carried out using a photodiode array detector at 282 nM. The column compartment was set at 35°C. The resolution between the enantiomer and isomers was found to be more than 2.0. The method was linear over the concentration range of limit of quantitation to 250% for isomers and enantiomers. The method was found to be robust with column temperature. The proposed chiral method is applicable for the determination of isomers and enantiomer of Valibenazine and was successfully used in the quality control of bulk drug manufacturing and pharmaceuticals.

Estimation of purity of antimicrobial lead compound sulfonamide-anthranilate derivative methyl-ester-toluene-sulfonamide using LC to develop a new drug application.

The newly synthesized lead molecule methyl-ester-toluene-sulfonamide is the combined derivative of sulfonamide-anthranilate. It was estimated by gradient elution using 0.1% triethylamine in water with pH 2.0 as mobile phase A and the mixture of acetonitrile and tetrahydrofuran in the ratio of 975:25 (v/v) as mobile phase B at a flow rate of 0.8 ml/min and 210 nm wavelength on an Agilent 1260 infinity series HPLC system equipped with a diode array detector. The column used was ACE 3 C18-PFP (250 × 4.6 mm, 3 µm i.d.) operating at 40°C. The gradient program was time (min)/% B: 0.0/50, 3.0/50, 15.0/70, 25.0/90, 30.0/90, 31/50, and 38/50. The method is simple, accurate, rapid, and selective. The method was linear with a concentration range of 1.6-240 µg/ml. The accuracy data obtained were 98.5-100.5%. The method validation data and quality by design-based robustness study results indicate that the developed method is robust and fit for routine use in the quality control laboratory. Therefore, the ready availability of the method can be useful in pharmaceutical new drug development.