Soft tissue contusion repairing effects of Hong Yao with different penetration enhancers

Hong Yao aerosol (HYA) is a new dosage form developed from Hong Yao, a traditional Chinese medicine preparation, which has the efficacy of promoting soft tissue contusion repair, anti-inflammation, and analgesia.

To evaluate the soft tissue contusion repairing, anti-inflammatory and analgesic effects of HYA formulations with different penetration enhancers (PE) and to quantify the transdermal absorption of HYA component.

Three preparations of HYA with different PEs were made: DMSO preparation (5% DMSO as additional PE), Azone preparation (3% azone as additional PE), and NAPE preparation (no additional PE). Four in vivo rodent models were employed to evaluate the pharmacodynamic effects of the HYAs: mouse soft tissue contusion model, rat paw edema model, mouse ear swelling model, and mouse analgesia model of electric-stimulated foot. In vitro skin penetration experiment was applied to evaluate the transdermal absorption of HYA components.

All HYA preparations showed effects on soft tissue contusion repairing, anti-inflammation, and analgesia compared with the blank control (p<0.05). There was no significant difference among the three preparations. Pathological variation of mice skin and the pain response time (PRT) reduction phenomena indicated that DMSO preparation induced skin irritation. In vitro skin penetration experiment showed no significant difference between DMSO and NAPE on absorption enhancement of ferulic acid from HYA.

NAPE preparation was considered as best and Menthol/borneol (6.3%, W/W, 4:1.75) in HYA might be a good PE combination.