Background: As the main medicinal powder for drawing out pus and removing necrotic tissue in external therapies of traditional Chinese surgery, Sheng Powder has made great contributions to the treatment of inflammatory wounds and has the unique bactericidal and decay-discharging function that can not be replaced by antibiotics. However, Sheng Powder has toxicity because it contains mercury. So far, there is no clinical research on the standards of dose and usage of Sheng Powder and there is a lack of objective and quantitative criteria for operating standards and monitoring of toxicity and side effects. Therefore, the authors choose Jiuyi Powder, one of the most commonly used Sheng Powder, to evaluate the safety of its external use, and form a standardization program for clinical implementation.
Methods and design: This study is a nonrandomized, nonblinded, self-controlled case study. There will be two key stages in the study. In stage one, 10 patients with plasma cell mastitis will be enrolled. The patients will receive continuous external application of Jiuyi Powder with a fixed dose (160 mg/d). Blood mercury and urine mercury levels will be dynamically tested at different time intervals, and the observation of pharmacokinetic parameters will be conducted after Jiuyi Powder has been absorbed by the surface of the wound. In stage two, 30 patients with each of the four conditions including postoperative wounds of head or facial surgeries, plasma cell mastitis, anal fistula and chronic absorption ulcer of the shank will be enrolled, respectively. According to the dose of 1.5 mg/cm ², Jiuyi Powder will be externally applied to the wound surface for 14 d. On the basis of the first-phase study, the test time will be chosen and the toxicity outcome will be detected to evaluate the safety of external application of Jiuyi Powder and to establish recommendations for standardized clinical use.
Discussion: The purpose of this study is to evaluate the safety of the external application of Jiuyi Powder through a two-stage study. The pharmacokinetic parameters of external application of Jiuyi Powder at the clinical dose range, the changes in blood and urinary mercury levels and related safety indexes will be observed on different wounds located in different positions externally. The evaluation of whether Jiuyi Powder could be a routine medication for drawing out pus and removing necrotic tissue in inflammatory and refractory wounds will be stated.
Trial registration number: ChiCTR-TNC-11001366.

Key words: Jiu-yi powder, safety, standardization, external therapy