Stability indicating RP-HPLC method for methylcobalamin determination in different dosage forms: Application to photodegradation kinetics and pH rate profiling

J Sep Sci. 2022 Aug;45(15):2877-2886. doi: 10.1002/jssc.202200132. Epub 2022 Jun 14.

Abstract

A stability-indicating RP-HPLC method for methylcobalamin determination was developed. Stress degradation under variable conditions was carried out. Methylcobalamin had pronounced susceptibility to hydrolysis under acidic, alkaline, and photolytic conditions; further study of photolytic degradation kinetics and pH rate profiling over pH range 2-11 was carried out. Photodegradation of methylcobalamin followed zero-order kinetics with half-life 0.99 h equivalent to 1971.53 lux. Methylcobalamin followed pseudo-first-order kinetics upon exposure to acidic and alkaline hydrolysis with highest stability at pH 5 and least stability at pH 2. Optimization of chromatographic conditions was performed using two level full factorial design, and chromatographic analysis was executed using Inertsil column (250 × 4.6 mm, 5 μm) maintained at 25 C. Elution was carried out using 25 mM potassium dihydrogen phosphate (pH adjusted with phosphoric acid to 3.8): methanol:acetonitrile (55:35:10, v/v) as mobile phase. The flow rate was 1.0 ml/min. Detection was carried out at 220 nm using diode array detector. The method was validated as per ICH guidelines; the linearity was over concentration range 2-160 μg/ml with coefficient of determination 0.9995. The method was effectively applied for determination of methylcobalamin in Cobalvex ampoule, Cobal tablet, Cobal-F tablet, and Methyltechon oral dissolvable film without interfering from excipients within run time 6 min.

Keywords: degradation kinetics; factorial design; methylcobalamin; photodegradation; stress degradation.

MeSH terms

  • Chromatography, High Pressure Liquid* / methods
  • Drug Stability
  • Hydrogen-Ion Concentration
  • Kinetics
  • Photolysis
  • Reproducibility of Results
  • Tablets / chemistry
  • Vitamin B 12 / analogs & derivatives

Substances

  • Tablets
  • mecobalamin
  • Vitamin B 12