Application of dry elixir system to oriental traditional medicine: Taste masking of peonjahwan by coated dry elixir

Peonjahwan, an oriental traditional medicine composed of crude herbal drugs and animal tissues is bitter and poorly water-soluble. To mask the bitterness of peonjahwan and enhance the release of bilirubin, one of the crude active ingredients of peonjahwan, peonja dry elixir (PDE), was prepared using a spray-dryer after extracting the crude materials in ethanol-water solution. Coated peonja dry elixir (CPDE) was then prepared by coating the PDE with Eudragit acrylic resin. Panel assessed bitterness and release test of bilirubin from PDE and CPDE were carried out and compared with peonjahwan atone. PDE was found to have little effect upon the reduction of the bitterness of peonjahwan. However, the bitterness of CPDE was found to reduce to 1/4 of that of peonjahwan due to the encapsulation of crude active ingredients by the dextrin and Eudragit shell (P<0.05). The release rate of bilirubin from PDE and CPDE for 60 min increased about 3.5- and 2.5- fold, respectively, compared to peonjahwan at pH 1.2. It is concluded that CPDE, which masked the bitterness of peonjahwan and enhanced the release of bilirubin, is a preferable delivery system for peonjahwan.