A novel method for the determination of chemical purity and assay of menaquinone-7. Comparison with the methods from the official USP monograph

[Display omitted] •HPLC UV method for simultaneous determination of MK7 purity and assay was developed.•The proposed methodology can be applied for MK7 samples of different purity.•Low time, solvent and sample consumption, high selectivity and accuracy of the method.•The method is superior to the methods published in the USP Monograph.•The use of USP methodology leads to serious overestimation of MK7 purity and assay. An HPLC method with UV detection and separation with the use of a C30 reversed phase analytical column for the determination of chemical purity and assay of menaquinone-7 (MK7) in one chromatographic run was developed. The method is superior to the methods published in the USP Monograph in terms of selectivity, sensitivity and accuracy, as well as time, solvent and sample consumption. The developed methodology was applied to MK7 samples of active pharmaceutical ingredient (API) purity, MK7 samples of lower quality and crude MK7 samples before purification. The comparison of the results revealed that the use of USP methodology could lead to serious overestimation (up to a few percent) of both purity and MK7 assay in menaquinone-7 samples.