Novel self-emulsifying controlled release tetrahydrocurcumin pellets coated with an aqueous-based system

The objective of this study was to develop the controlled release self-emulsifying pellets of tetrahydrocurcumin (THC) with aqueous-based film coating. The use of self-emulsifying system provided better solubility and absorption of hydrophobic THC whereas the controlled release system could prolong the drug release. The composition comprising 1.18% of THC and 13.27% of the liquid self-emulsifying system (Cremophor EL, Labrasol, Labrafac PG, and Capryol 90) mixed with 59.72% of solid pellet excipients (pregelatinized starch and microcrystalline cellulose), and the pellets were coated with 25.83% of polymers (hydroxypropyl methylcellulose and ethycellulose). The sub-coating layer I of a water-soluble hydroxypropyl methylcellulose polymer with the top-coating layer II of water insoluble ethycellulose polymer could refine the control of the in vitro release of THC in an oil-in-water microemulsion, with a particle size of less than 50nm. The optimum formulation provided a controlled release of 60% of THC over a 24h period, which was significantly higher than that of unformulated THC (only 30%). The formulation approach based on an aqueous solvent system offers the possibility of formulating and controlling the in vitro release of poorly water-soluble herbal drugs from solid-lipid dosage forms with economy and environmental safe.

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