Tailoring Drug Release Kinetics in Lipophilic Drug-Loaded Oral Microemulsions: Impact of Surfactant Chain Length

Abstract

Purpose

The objective is to study the influence of surfactant chain lengths on the solubilization capacity and release pattern from the Rosuvastatin calcium-loaded microemulsion.

Methods

In the study, rosuvastatin calcium was incorporated into oil-in-water microemulsion formulations using surfactants of varying chain lengths. The developed formulations were then characterized for physicochemical properties, along with stability, release profile and in vitro intestinal permeability. The cytotoxicity assay was performed to assess the safety of microemulsion formulation.

Results

The stability of microemulsion formulation increases with the increase in carbon chain as indicated with smaller globule size, excellent dispersibility, and reduced dynamic surface tension. Furthermore, the stable rosuvastatin calcium-loaded microemulsion showed relatively higher transmittance value which was observed to be decreased with their dilution over time. The release study showed that the formulations with longer chain length surfactants exhibited higher rate of drug release in both SGF and SIF. The release kinetics of the developed formulation follow zero order equation and release mechanism was identified as supercase-II transport type diffusion. Additionally, the selected microemulsion system did not show any signs of cytotoxic potential on HCT-116 cells.

Conclusions

It can be concluded that the use of surfactant with longer chain length showed improvement in the transport of the drug through the lipid-rich membrane of intestine. The stable microemulsion allows regulation of epithelial cells and facilitating the paracellular transport of the drug.

Graphical Abstract