Ravindra B. Saudagar

Nasal mucosa has been considered as a potential administration route to achieve faster and higher levels of drug absorption because it is permeable to more compounds than the gastrointestinal tract. It is an attractive route of administration due to lack of pancreatic and gastric enzymatic activity, neutral pH of the nasal mucus and less dilution by gastrointestinal contents. In-situ gel forming systems have been developed to prolong the nasal residence time of a drug and improve nasal bioavailability. Fexofenadine hydrochloride is one of the most widely used drugs for allergic rhinitis. It is an anti-histaminic and is available in oral dosage forms. The present work is aimed at designing a gel formula for nasal administration. To enhance therapeutic effect of the nasal formulation of fexofenadine hydrochloride pH sensitive polymers were used. Xanthan gum and Carbopol 934 were selected as independent variables in the factorial design. Solubility of the drug in the formulation was enhanced by using Tween 80. Evaluation parameters of the formulation like pH, clarity; rheological study both formulation i.e. solution and performed gel, gelling time, drug content, in-vitro drug diffusion study, stability studies were performed. The formulations so designed shall enhance bioavailability of drug and offer better therapeutic outcomes, offer aesthetically appealing dosage form to increase patient compliance and shall overcome side effects and limitations of other dosage forms of marketed preparations.

Enhancement of the solubility, dissolution and bioavailability of the drugs is the challenging task for the research sector. As many of the solubility enhancement techniques are available to achieve the desired goal, but the older techniques don’t show the expected results for solubility enhancement and bioavailability as well, and they are unstable also some time.  But today the scenario is different because the novel techniques of solubility enhancement are available, such as hydrotropy, supercritical fluid process, sonocrystallisation, inclusion complex system, spray drying, microwave assisted techniques, etc. this novel techniques have the ability to give the reproducible results for solubility enhancement in pharmaceutical product development.  present review article deals with the different techniques for the solubility enhancement of the poorly soluble drug candidates.