Determination of indinavir, potassium sorbate, methylparaben, and propylparaben in aqueous pediatric suspensions.

A gradient, reversed phase, HPLC method was developed for simultaneous analysis of potassium sorbate, methylparaben, propylparaben, and indinavir in aqueous suspensions that contain a proprietary orange flavoring and Magnasweet sweetener enhancer (MacSanrews and Forbes Company, Magnasweet product brochure). The chromatographic separation is performed on an Eclipse XDB-C8 column using a gradient run with an analysis time of 35 min. The mobile phase consists of acetonitrile and acetonitrile:citrate buffer, pH 4.0 (20:80 v/v). The method successfully separates the three preservatives, indinavir (active ingredient), the orange flavoring, the Magnasweet species, and the indinavir lactone degradate. Recovery, linearity, and precision results for the three preservatives and indinavir are described. The method applies to two types of formulations: Xanthan Gum suspension and NanoSystems suspension.