Nanoemulsions loaded Carbopol? 934 based gel for intranasal delivery of neuroprotective Centella asiatica extract: in-vitro and ex-vivo permeation study

摘要

The objective of the present study was to develop a formulation for sustained release of phytothera-peutics through nasal membrane for brain targeting (anti-Alzheimer) in order to overcome their low residence time and poor nasal permeability issues. A dual approach containing nanoemulsions within gel (NE-gels) was used to achieve the objectives utilizing biocompatible biomateri-als. Nanoemulsions were characterized for particle size and zeta potential. NE-gels loaded with Centella asiatica (CA) extract were developed using Carbopol? 934 and were characterized for rheological properties (spreadability, viscosity), drug release and prolong anti-oxidant profile. In vitro nasal permeation and free radical scavenging activity were performed to investigate their expected sustained pharmacological responses. With increasing Carbopol content, viscosity of NE-gels was found to increase up to 6237.3 ± 1.1 cp which adversely influenced the spreadability (3.06 ± 0.98) of the NE-gels. Enhancement in sustained release of the CA extract across the nasal membrane (four fold; up to 48 h) as well as retention time in nasal cavity (four fold; i.e. 48 h) were observed with NE-gels in comparison to CA solution (i.e. 12 h). In vitro nasal permeation study showed 10 folds enhancement of percentage drug permeation across the nasal mucosa in comparison to extract solution while three folds increase in free radical scavenging activity was observed by NE-gel (i.e. 48 h) in comparison to nanoemulsion (i.e. 24 h), respectively. Extensive in vitro investigation established these nanocarriers as suitable nanoformulations for brain targeting of water insoluble phytochemicals.