Preparation and dissolution characteristics of Compound Danshen freeze-dried emulsion / 中草药

ABSTRACT

Objective: To improve in vitro dissolution of lipophilic constituents in Compound Danshen Tablet, a novel freeze-dried emulsion was designed and developed. Methods: Compound Danshen liquid emulsion was prepared by high-speed shearing, following by high pressure homogenization process. The oil phase and cryoprotectants were optimized by uniform design test, using physical appearance and redispersibility as evaluation indexes. The in vitro dissolution profile of tanshinone IIA and borneol in the freeze-dried emulsion and Compound Danshen Tablet was determined in artificial gastric juice and artificial intestinal juice containing 0.5% sodium lauryl sulfate (SDS). Based on the appearance, average particle size and zeta potential, the stability of freeze-drying emulsion was investigated. Results: The developed Compound Danshen freeze-dried emulsion had good physical appearance, meanwhile maintained a good redispersibility and stability, when 10% medium chain triglycerides (MCT) was adopted as oil phase of liquid emulsion and 18% maltose combined with 0.25% beta-cyclodextrin was optimized as cryoprotectants. In artificial gastric juice, the accumulated dissolution rates of tanshinone IIA and borneol in Compound Danshen freeze-dried emulsion reached up to (94.8 ± 2.8)% and (97.4 ± 2.9)% at 30 min, respectively. However, the accumulated dissolution rate of borneol in the tablet was only (23.3 ± 3.4)% at 120 min, while tanshinone IIA showing no dissolution. In artificial intestinal juice, the accumulated dissolution rates of tanshinone IIA and borneol in the tablet rose to (42.5 ± 2.7)% and (74.4 ± 1.8)% at 120 min, but they were still much lower than that in the freeze-dried emulsion which reached up to (97.8 ± 1.9)% and (92.7 ± 3.5)%. After one year's storage, there were no significant changes of the stability evaluation index for freezing dry emulsion. Conclusion: The dissolution rates of lipophilic constituents in Compound Danshen freeze-dried emulsion increased significantly and exhibited a fast and fairly complete drug release, which provides a potential and promising formulation to improve bioavailability of the original dosage form of tablet. Its physical stability is good.