Abstract:

[Objective] This study was conducted to characterize the pharmacokinetics of chlortetracycline hydrochloride ultra-fine powder in ducks. [Method] Using the raw powder of chlortetracycline hydrochloride with ordinary particle size as material, the ultra-fine powder with particle size of 800 mesh was prepared by airflow grinding technology. Subsequently, by adding a certain amount of appropriate accessories, the soluble ultra-fine powder containing 20% chlortetracycline hydrochloride was prepared. The stability of the soluble ultra-fine powder was evaluated by influencing factor test and accelerated test. A total of 30 Shaoxing ducks aged 90 days were randomly assigned to one of the following three groups: group A （n=10）, group B （n=10） or group C （n=10）, which were given a single dose of the chlortetracycline hydrochloride soluble powder [15 mg/（kg·BW）, calculated by chlortetracycline hydrochloride] prepared using raw materials with particle sizes of 60 mesh, 800 mesh (ultra-fine powder) and 80 mesh by oral gavage, respectively. The pharmacokinetics of the chlortetracycline hydrochloride soluble powder prepared with raw materials of different particle sizes in ducks were characterized and statistically compared. [Result] The prescription and technology of the soluble ultra-fine powder prepared using raw material with particle size of 800 mesh was stable and feasible, and the quality was proved to be reliable by stability test. The main pharmacokinetic characteristics of the chlortetracycline hydrochloride soluble powder prepared with raw materials of different particle sizes in ducks were as follows: the T_max in group B was significantly （P<0.05） faster than that in groups A and C; the AUC_0-t and C_max in group B were significantly （P<0.05) higher than those in groups A and C; the t_1/2 in group B was significantly （P<0.05） longer than that in groups A and C, while there was no significant （P>0.05） difference between groups A and C; the in vivo MRT in group B was significantly （P<0.05） longer than that in groups A and C. [Conclusion] When given the same dose of 15 mg/（kg·BW） of chlortetracycline hydrochloride in ducks, the soluble ultra-fine powder peaked in blood concentration at 1.5 hours post administration, indicating that it had superior absorption rate and effective blood concentration maintenance duration to the soluble powder prepared with raw materials of ordinary particle sizes. The pharmacokinetic data obtained in this study may provide references for the use of chlortetracycline hydrochloride in clinical treatment of animal diseases.

Key words: chlortetracycline hydrochloride ultra-fine powder, preparation, pharmacokinetics, ducks