An examination of carbopol hydrogel/organogel bigels of thymoquinone prepared by microwave irradiation method.

Nigella sativa L. is shown wide spread over the world and contains many useful phytochemicals. Much of the biological activity of the seeds has been shown due to the presence of thymoquinone (TQ). Its poor aqueous solubility of TQ hinders its delivery to target site. The aim of this work was to prepare TQ bigels composed of Carbopol 974 P NF (C974) in PEG 400 (organogel) or C974 in water (hydrogel) with microwave heating method. A novel technique, high speed homogenization followed by microwave heating, was used to prepare organogels. The pH, electrical conductivity, differential scanning calorimetry, rheological properties, and morphological structure of the formulations have been evaluated, and the effect of microwave on drug content and TQ antioxidant activity has been investigated. The bigels of TQ were successfully produced via high-speed homogenization followed by microwave-assisted heating for the first time in this study. Highly lipophilic TQ was successfully dissolved in organogel, and it was not affected from the microwaves. It can be stated that microwave heating is a promising method to obtain C974 organogels and thus bigels with appropriate above indicated investigated physicochemical characteristics. The time and energy consumption could be decreased with microwave-assisted heating, especially for gel preparation in the field of pharmaceuticals.