Stability indicating reverse phase (RP)-high-performance liquid chromatography method development and validation for the simultaneous estimation of olanzapine and samidorphan in bulk and tablets

Background
Patients with schizophrenia are given a combination tablet combining olanzapine (OLA), an atypical antipsychotic and samidorphan (SAM), an opioid receptor antagonist.
Objectives
In bulk and tablet dosage forms, a stability-indicating reverse phase (RP)-high-performance liquid chromatography technique for the simultaneous determination of OLA and SAM has been developed and validated.
Materials and methods
The chromatographic analysis was performed using an isocratic mobile phase of 0.1% formic acid in water : methanol : acetonitrile (10 : 40 : 50, v/v) at a flow rate of 0.8 ml/min, and the eluents were monitored at an isosbestic point of 285 nm.
Results and conclusion
The suggested method’s specificity, precision, accuracy, linearity, and robustness were all validated according as per International Conference on Harmonization guidelines. The method’s stability was validated by forced degradation experiments. Retention times for OLA and SAM were 2.85 and 4.79 min, respectively. The method was found to be precise and accurate. SAM linearity was found to be between 14.0 and 45.0 µg/ml, whereas OLA linearity was found to be between 22.5 and 67.5 µg/ml. The limit of detection (LOD) and limit of quantification (LOQ) of OLA were 2.65 and 8.85 µg/ml, respectively, whereas the LOD and LOQ of SAM were 8.12 and 27.06 µg/ml, respectively. As a result, the suggested high-performance liquid chromatography method for the quantification of OLA and SAM was reliable, repeatable, accurate, and sensitive.