Approaches to the Development of New Simple Rapid HPLC–Photodiode Array Method for the Simultaneous Determination of Levomenthol and Ibuprofen in Gel Pharmaceutical Formulation.

We have developed a new approach in creating a simple, fast analytical method for the simultaneous determination of ibuprofen and menthol in pharmaceutical dosage form by using an HPLC‐photodiode array system with a selected reversed‐phase column after numerous experiments with columns covering the full spectrum of polarities; C‐18, C‐8, phenyl, cyanopropyl, and silica‐based liquid chromatography matrices. The main problem and challenge for the development method was using many liquid chromatography features to detect and measure the analyte molecule of menthol, which is almost UV‐invisible, having a structure without any chromophore in its structure. The enormous UV‐absorbing characteristics between ibuprofen and menthol complicate the creation of a simple, rapid, reproducible, rugged, and accurate simultaneous analytical method with high throughput character. Low injection volumes were used for conceptual purposes. The final analytical method has been developed with one simple sample preparation for the determination of two distinct analytes, always determined with two different techniques or one with more sophisticated detection systems and separate sample preparation. As we could check and compare, the proposed HPLC simultaneous quantification method for levomenthol and ibuprofen is one of the simplest and shortest analytical methods for mutual determination in pharmaceutical dosage forms. [ABSTRACT FROM AUTHOR]