Active Targeting of Drugs and Bioactive Molecules via Oral Administration by Ligand-Conjugated Lipidic Nanocarriers: Recent Advances.

The oral route is the most widely accepted and commonly used route for administration. However, this route may not be suitable for certain drug candidates which suffer from the problem of low aqueous solubility and gastrointestinal absorption and extensive first-pass effect. Nanotechnology-based approaches can be taken up as remedies to overcome the disadvantages associated with the oral route. Among the various nanocarriers, lipidic nanocarriers are widely used for oral delivery of bioactive molecules owing to their several advantages. Active targeting of bioactive molecules via lipidic nanocarriers has also been widely attempted to improve oral bioavailability and to avoid first-pass effect. This active targeting approach involves the use of ligands grafted or conjugated onto a nanocarrier that is specific to the receptors. Active targeting increases the therapeutic efficacy as well as reduces the toxic side effects of the drug or bioactive molecules. This review mainly focuses on the challenges involved in the oral delivery of drugs and its approaches to overcome the challenges using nanotechnology, specifically focusing on lipidic nanocarriers like liposomes, solid lipid nanoparticles, and nanostructured lipid carriers and active targeting of drug molecules by making use of ligand-conjugated lipidic nanocarriers.

Nano-transfersomal formulations for transdermal delivery of asenapine maleate: in vitro and in vivo performance evaluations.

CONTEXT: Asenapine maleate (ASPM) is an antipsychotic drug for the treatment of schizophrenia and bipolar disorder. Extensive metabolism makes the oral route inconvenient for ASPM. OBJECTIVE: The objective of this study is to increase ASPM bioavailability via transdermal route by improving the skin permeation using combined strategy of chemical and nano-carrier (transfersomal) based approaches. MATERIALS AND METHODS: Transfersomes were prepared by the thin film hydration method using soy-phosphatidylcholine (SPC) and sodium deoxycholate (SDC). Transfersomes were characterized for particle size, polydispersity index (PDI), zeta potential (ZP), entrapment efficiency, surface morphology, and in vitro skin permeation studies. Various chemical enhancers were screened for skin permeation enhancement of ASPM. Optimized transfersomes were incorporated into a gel base containing suitable chemical enhancer for efficient transdermal delivery. In vivo pharmacokinetic study was performed in rats to assess bioavailability by transdermal route against oral administration. RESULTS AND DISCUSSION: Optimized transfersomes with drug:SPC:SDC weight ratio of 5:75:10 were spherical with an average size of 126.0 nm, PDI of 0.232, ZP of -43.7 mV, and entrapment efficiency of 54.96%. Ethanol (20% v/v) showed greater skin permeation enhancement. The cumulative amount of ASPM permeated after 24 h (Q24) by individual effect of ethanol and transfersome, and in combination was found to be 160.0, 132.9, and 309.3 µg, respectively, indicating beneficial synergistic effect of combined approach. In vivo pharmacokinetic study revealed significant (p < 0.05) increase in bioavailability upon transdermal application compared with oral route. CONCLUSION: Dual strategy of permeation enhancement was successful in increasing the transdermal permeation and bioavailability of ASPM.