Lack of gender effect on the pharmacokinetics of oxytetracycline in Fenneropenaeus chinensis after intramuscular administration

Abstract

Fenneropenaeus chinensis, an economically important shrimp species, currently suffers from epizootic diseases due to high density stocking and bacterial infections. Oxytetracycline (OTC) has been widely used to treat various systemic bacterial infections in shrimp farming. In the present study, the effect of gender on pharmacokinetics of OTC in F. chinensis was investigated. The OTC concentrations in hemolymph of shrimp after single intramuscular administration (75 mg OTC per kg body weight) were analyzed by high performance liquid chromatography and best described with a two-compartment open model which is characterized by a short elimination half-life, low clearance, and a relatively large apparent volume of distribution. The pharmacokinetic equations were C t = 58.54e −0.38t + 11.67e −0.04t for females; and C t = 27.94e −0.28t + 14.87e −0.04t for males. The distribution and elimination half-lives of OTC were 1.82 and 19.58 h, respectively, in females and 2.50 and 16.11 h, respectively, in males at 22℃. The areas under the drug concentration curve were 480 mg L −1 h −1 in females and 430 mg L −1 h −1 in males. The total body clearance of the drug was 157.11 mL kg −1 h −1 in females and 172.47 mL kg −1 h −1 in males. The apparent volume distribution was 4.44 in females and 4.01 L kg −1 in males. There was no significant difference in pharmacokinetic parameters between female and male shrimps, indicating that there is no need to consider the gender effect in clinical use of OTC in F. chinensis farming.

Pharmacokinetics studies of eugenol in Pacific white shrimp (Litopenaeus vannamei) after immersion bath

“…In the present study, the t 1/2z values of eugenol are fitted to be 21.4 h and 79.3 h in the hepatopancreas and muscle after a long-term immersion (Table 5 ), which is good consistent with the results described above, suggesting a faster depuration in hepatopancreas than that of muscle. Moreover, the t 1/2z of eugenol in shrimp is obviously lower than those of other chemical compounds, such as sulfamethoxazole in Pacific white shrimp (13.76 h) [ 51 ], enrofloxacin in Pacific white shrimp (19.8 h) [ 21 ], oxytetracycline in female and male F. chinensis (19.58 and 16.11 h) [ 59 ] and oxolinic acid in black tiger shrimp (17.7 h) [ 60 ]. These results suggest that eugenol has a more rapid elimination in shrimp.…”