Solid-phase extraction and HPLC analysis of methylparaben and propylparaben in a concentrated antibiotic suspension.

An accurate and precise solid-phase extraction coupled with high performance liquid chromatography (SPE/HPLC) method developed for the quantification of antimicrobial preservatives (methylparaben and propylparaben) in oxytetracycline injectable suspension is described in this article. The SPE technique was necessary to quantify the preservatives since the high concentration of the drug and excipients was masking low levels of preservatives, making quantification difficult. This developed HPLC method was stability-indicating and found to be linear between 1.

Determination of polysorbate 80 in parenteral formulations by high-performance liquid chromatography and evaporative light scattering detection.

Drugs that are not very soluble in aqueous formulations are solubilized with surfactants such as polysorbate 80. In order to evaluate the stability of excipient such as polysorbate 80 in drug formulation, a rapid chromatographic methodology is desired; however, polysorbate 80 does not have a strong chromophore for monitoring by absorption spectrometry. A simple and fast method for the analysis of polysorbate 80 in pharmaceutical formulations was developed using high-performance liquid chromatography with evaporative light scattering detection (ELSD).