Validation of a simple RP-HPLC method developed for the quantification of meta-cresol in parathyroid hormones formulation.

Aim: To develop and validate a rapid and sensitive reverse phase high performance liquid chromatography (RP-HPLC) method with UV detection for quantification of meta-cresol (m-cresol) in pharmaceutical preparation of parathyroid hormone (1-34) (PTH).

Materials And Methods: Chromatography was performed on a Jupiter RP C-18 (4.6 mm ID × 250 mm L, porosity 300 Å, particle size 5 μm) with a guard column (reversed-phase C18 column of 4.6 mm ID × 12.5 mm L, porosity 300 Å, particle size 5 μm) using a mobile phase containing 0.1% TFA in 60% methanol with isocratic program at 1.0 mL/min flow rate. Detection was carried out at 217 nm. The method was validated as per ICH guidelines for linearity (correlation coefficient = 0.99), range, accuracy, precision, and robustness (n = 9 during accuracy parameter whereas n =15 during linearity and range parameter and n = 6 during repeatability). Robustness was confirmed by considering two factors; age effect of the mobile phase and test sample and with different columns during method development.

Results: The method was linear over the concentration range of 75-120 μg/mL. The precision of the method in terms of relative standard deviation was evaluated from intra- and inter-day replicate injections of system suitability standards of m-cresol using different equipment and different columns. Components of within- and between-batch variances were found to be below 2% (n = 30) and 3%, respectively, which constituted an acceptable level of variation. Retention time was found to be about 5.2 min and 10.9 min for m-cresol and PTH, respectively.

Conclusion: The developed method thus has the potential of being useful for routine quality control of m-cresol.