[Study on Chinese herbs' volatile oil micro-emulsions by means of pseudo-ternary phase diagram].

OBJECTIVE: To optimize the formulation of Chinese herbs' volatile oil micro emulsion. METHODS: Sreened the formulation of blank micro-emulsion and the formulation of micro-emulsion contained volatile oil by means of pseudo-ternary phase diagram. RESULTS: System of isopropyl myristate, polyoxyethylene hydrogenated castor oil, absolute ethyl alcohol and water could formed the largest area of micro-emulsion. The optimal formulation of micro-emulsion contained volatile oil was: volatile oil consisted of 2.852%, isopropyl myristate 6.65%, polyoxyethylene hydrogenated castor oil 30.42%, absolute ethyl alcohol 7.605% and water 52.47%. CONCLUSIONS: Using pseudo-ternary phase diagram to optimize the formulation of Chinese herbs' micro-emulsion is scientific and feasible. The volatile oil's solubility is also increased by made of oil-in-water type micro-emulsion and insured the stability.