Simultaneous determination of ibuprofen and hydroxypropylmethylcellulose (HPMC) using HPLC and evaporative light scattering detection.

Ibuprofen may be crystallised in the presence of hydroxypropylmethylcellulose (HPMC) to improve its physical properties. This, however, creates problems with the simultaneous analysis of each ingredient. The analytical method developed utilised high performance liquid chromatography (HPLC) with a stationary phase designed for carbohydrate separation (GylcoSep N) and a mobile phase comprising methanol and water. Evaporative light scattering detection (ELSD) proved a suitable method for the analysis of both HPMC and ibuprofen. Data showed that HPMC and ibuprofen could be quantified in each other's presence. Validation studies indicated that the method was adequately accurate and precise. Baseline resolution was achieved between the two components. HPMC (1.1% w/w) was retained in ibuprofen crystals obtained from alcoholic HPMC suspensions.