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Key characteristics and modelling of bigels systems: A review.

Bigels and multi-component organogels : An overview from rheological perspective

Bigels as drug delivery systems: From their components to their applications

The aim of this study was to develop and characterize the mechanical, microstructural, and thermal behavior of a novel edible biphasic gel system also termed bigel. A combination of a gelatin hydrogel and rice bran wax (RBW)-based oleogel with soybean oil was used for bigel formulation. Bigels were prepared with four oleogel-to-hydrogel (OG:HG) ratios (50:50, 40:60, 30:70, 20:80) at three gelatin concentrations (5, 7, and 10% (w/w)). The RBW concentration remained constant at 10% (w/w). Bigels were analyzed using Fourier transform infrared spectroscopy (FTIR), differential scanning calorimeter (DSC), confocal laser scanning microscopy (CLSM), and small deformation rheology. CSLM images confirmed an oleogel-in-hydrogel system for all bigel formulations with an increase in oleogel proportion leading to increased oleogel droplet size and enhanced stability. Rheological characterization of the systems showed all bigel formulations, regardless of gelatin concentration and oleogel to hydrogel proportion, showed more solid than liquid (G′ > G″) character and frequency independence at 20 ℃. Bigels with higher OG:HG ratios, i.e., 50:50 and 40:60, consistently exhibited greater elastic modulus (G′) values than those of gels with lower OG:HG ratios, providing evidence of increased oleogel droplet interaction leading to enhanced mechanical properties. The rheological behavior of all bigels was accurately captured by the Boltzmann Sigmoidal model. FTIR and DSC analysis showed distinct peaks for the oleogel and hydrogel phases in all bigel samples with the absence of new thermal events, indicating a lack of interactions between components of both phases. Overall, the system is a “true” bigel that benefits from its two distinct phases and is kinetically stable.

Development of Novel Rice Bran Wax/Gelatin-Based Biphasic Edible Gels and Characterization of their Microstructural, Thermal, and Mechanical Properties

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.

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

The present study was aimed of design and evaluation of bigel containing flurbiprofen. Bigels are interesting innovative two phase systems that have been recently proposed as structured system for delivery of active ingredients. They possess the advantages of both hydrogel and organogel. Organogel was prepared by pluronic lecithin and hydrogel was prepared using HPMC. Bigels were prepared by mixing of organogel and hydrogel in appropriate ratio. Organogel and hydrogel was evaluated for pH, viscosity, extrudability and spreadabilty. Formulation F3 from organogel and formulation H3 from hydrogel was selected as optimized formulations and was used for the preparation of bigel. The prepared bigel was evaluated for pH, viscosity, extrudability, spread ability, in vitro drug release studies, ex vivo permeation studies, stability studies and skin irritation test. All formulations of bigel showed extended release out of which formulation B3 was selected as the optimized formulation on the basis of evaluation parameters. In vitro permeation release was found to be 89.99% at the end of 8 hrs. The release kinetics of flurbiprofen bigel followed Higuchi model. The bigels were found to be stable and skin irritation studies on Wistar rats showed that the prepared bigels were compatible. Based on the encouraging results bigels containing flurbiprofen can be used as extended release system.

Arjun Muaralidharan

Papers

Design and Evaluation of Bigels Containing Flurbiprofen