A stability-indicating HPLC method for simultaneous determination of morphine and naltrexone

• Answer to growing need for simultaneous analysis of morphine and naltrexone.
• Plotting effective parameters against peak retention times.
• Exploring the active ingredient and internal standard in biological fluids (urine and plasma).
• Applying method for simultaneous assaying of morphine and naltrexone in commercial product.

This study developed a stability-indicating reversed-phase HPLC method for the simultaneous determination of morphine sulfate and naltrexone hydrochloride content in bulk, Solid dosage forms and in-vitro dissolution samples to support product development and quality control efforts. Chromatographic separation of the pharmaceutical compound was achieved on a perfectSil™ MZ C18 column (250 × 4.6 mm, 5 μm) with an isocratic mobile phase composed of a mixture of acetate buffer (10 mM, pH 4, containing 0.1% of 1-heptanesulfonic acid sodium salt) and acetonitrile with 80/20 at a flow rate of 1.5 ml min−1. Both analytes were quantified using a photodiode array detector set at a wavelength of 280 nm and column temperature was set to 30 °C. naltrexone, morphine and a mixture of the two were subjected to thermal, peroxide, acid, base and photolytic degradation and their peak homogeneity was obtained using a photodiode array detector, demonstrating the specificity of method. These pharmaceuticals were spiked in biological fluid to examine method selectivity. The method was validated for system suitability, linearity, accuracy, precision, detection and quantification limits and robustness and was found it is acceptable in range of 2–250 μg ml−1 for morphine and 4–100 μg ml−1 for naltrexone.