| Qinhuang Qingfei Powder(QQP)composed of Radix Scutellariae,Radix et Rhizoma Rhei,Folium Eriobotryae and Radix et Rhizoma glycyrrhizae,can clear away lung heat,suppress cough and asthma,and is used for the prevention and treatment of respiratory symptoms of Infectious Laryngotracheitis(ILT).A preclinical study(including quality standard,main pharmacodynamics and safety)of QQP presented in this article was conducted to provide documentation for its use as a new veterinary drugs.To establish the quality standard of QQP,a qualitative analysis of Radix Scutellariae,Radix et Rhizoma Rhei,Folium Eriobotryae and Radix et Rhizoma glycyrrhizae was conducted by microscopic identification and thin layer chromatography(TLC)of the proposed formula.The concentration of Baicalin,a main component of Radix Scutellariae was determined simultaneously by High Performance Liquid Chromatography(HPLC).The chromatographic conditions included: elite C18 column(250 mm×4.6 mm,5 μm)with the mobile phase of methanol-water-phosphoric acid(47:53:0.2)at a flow rate of 1 mL/min,the detection wave length was 280 nm,column temperature was 40℃,and the injection volume was 20 μL.The linear range of the calibration was 0.241~1.208 μg(r=0.999).The accuracy,stability and reproducibility of RSDs were lower than 3.0%.The recovery rate was 100.49%(RSD=1.71%,n=9).These results met the requirements of good repeatability and stability.Additionally the four main herbs within the formula were confirmed by identifying their unique characteristics by microscopy examination.There were the same color spots on the chromatography corresponding positions between test samples and reference substance or reference drug,and no interference in negative control.These methods also showed satisfactory feasibility,specificity and repeatability,respectively.The determination of the main pharmacodynamics effects of QQP,namely anti-inflammatory,antitussive,expectorant and asthmatic,were carried out in vivo using the xylene-induced mouse auricle swelling model,concentrated ammonia-induced mouse cough model,the phenol red excretion in mouse trachea model and the effects on histamine and acetylcholine were conducted in guinea pigs.The results of the trials indicated QQP has obvious anti-inflammatory,antitussive,expectorant andanti-asthmatic effects.Baseline indexes of blood pressure,pulse and lung function were measured to lay the foundation of safety pharmacology study of QQP.The results showed that systolic blood pressure(SBP)was in the range of(130~176)mmHg.Diastolic blood pressure(DBP)was in(102~144)mmHg.Mean arterial pressure(MAP)was in(111~151)mmHg,and pulse(P)was in(276~412)times/min.Expired volume(TV)was in(0.41~2.23)mL and frequency(f)was in(141~255)times/min.Meanwhile,the safety pharmacology study of QQP was carried out.The cardiovascular system and respiratory indexes were detected by MC4000 non-invasive blood pressure meter and EMKA small animal non-invasive pulmonary function instrument,respectively.At the same time,the tests of sodium pentobarbital threshold(subthreshold)dose,mouse general state and autonomic activity and mouse functional exercise were conducted,which could illustrate the effects of the drugs on nervous system.The results showed that QQP had no adverse effect on the cardiovascular system,respiratory system and nervous system in conscious rats.Finally,acute and long-term toxicology studies of QQP were conducted.The results of the acute toxicity test showed that the LD50 of QQP was more than 5000 mg/kg,which demonstrated that it has a large margin of safety.In the long-term toxicity test,the differences were not significant in body weight,water intake,feed intake,hematological index or blood biochemical index between dose groups and the control group,and no lesion was observed within histopathological samples.In summary,quality of QQP could be controlled and feasible.QQP is effective,safe and non-toxic,and a clinically safe drug,which has a wide range of clinical application prospects. |
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