Bigels: A newer system – An opportunity for topical application

Introduction: A gel is a solid or semisolid system composed of at least two parts, namely a condensed mass containing and interpenetrating a liquid. Hydrogel, emulgel and organogel are novel gel systems that are widely known but have some drawbacks. For example, hydrogel delivers hydrophilic but not poorly water-soluble drugs and has a lower ability to penetrate the stratum corneum, organogel has a greasy nature that causes stickiness and difficulty in removal and emulgel has different mechanical phases that cause instability. This impediment can be solved by using a unique and innovative formulation termed bigels. Method: The aqueous phase is typically made by a hydrophilic polymer, while the organic phase is comprised of gelled vegetable oil due to the presence of an organogelator. For the bigel manufacturing process, the percentage of the respective gelling agent in each phase, the organogel/hydrogel ratio, as well as the mixing temperature and speed, should be considered. The presence of desirable characteristics in both hydrogels and organogels increases patient compliance as well as the loading capacity of both lipophilic and hydrophilic drugs. Result: The substantial focus of this descriptive review is to look at the possible correlations (i.e. cross-linked polymer structures) among various parts of hybrid systems (i.e. bigels or multi-component organogels). Bigels are systems formed by combining a hydrogel with an organogel. Discussion: So far, researchers have mostly investigated bigel systems for regulated drug administration in topical applications. These bigels are investigated in research, yet to find popularity in the market.