A Compendium of Bioavailability Enhancement via Niosome Technology

Bioavailability is the dissimilarity between the total amount of drug exposure to a person and the actual dose received by his body. The difference in bioavailability between formulations of a given drug can have clinical implications.

Poor aqueous solubility, inappropriate partition coefficient, high first-pass metabolism, narrow absorption window, and acidic pH of the stomach are the main reasons behind the low bioavailability of drugs. There are three substantial methods to vanquish these bioavailability issues, namely pharmacokinetic, biological, and pharmaceutical approaches.

In the pharmacokinetic approach a drug molecule is improved by making alterations in its chemical structure. In the biological approach, the course of administration of the drug is changed; for example, if a drug has very less oral bioavailability, it can be injected as parenteral or some other route if feasible. In the pharmaceutical approach to enhance bioavailability, the physiochemical properties of the drug or formulation are modified. It is cost-effective, less time-consuming, and the risk factor is also minimum. Co-solvency, particle size reduction, hydrotrophy, solid dispersion, micellar solubilisation, complexation, and colloidal drug delivery systems are some of the commonly used methods to enhance the dissolution profiles of drugs via the pharmaceutical approach. Similar to liposomes, niosomes are also vesicular carrier systems but non-ionic surfactants are used instead of phospholipids in their formulation, i.e., their bilayer is comprised of non-ionic surfactants that encircle the aqueous compartment. The niosomes are presumed to raise the bioavailability of poorly water-soluble drugs by increasing their uptake by the M cells present in Peyer's patches of lymphatic tissues of the intestine.

Niosomal technology has become an attractive method to overcome several limitations due to its various merits like biodegradability, high stability, non-immunogenic nature, low cost, and flexibility to incorporate lipophilic as well as hydrophilic drugs. The bioavailability of many BCS class II and IV drugs has been successfully enhanced using niosomal technology, like Griseofulvin, Paclitaxel, Candesartan Cilexetil, Carvedilol, Clarithromycin, Telmisartan, and Glimepiride. Niosomal technology has also been exploited for brain targeting via nasal delivery for many drugs like Nefopam, Pentamidine, Ondansetron HCl, and Bromocriptine mesylate. Based on this data, it can be concluded that niosomal technology has increased importance in bioavailability enhancement and improving the overall performance of molecules in vitro and in vivo. Thus, niosomal technology holds tremendous potential for scale-up applications, overcoming the drawbacks of conventional dosage forms.