The study was done to compare the pharmacokinetic and pharmacodynamics of 50 mg/kg b.wttetracycline hydrochloride (TC-hcl) and tetracycline nanoemulsion (TC-nm) formulasin rabbits and detection of their effect on stander and field bacterial strains. After oral TC concentration in plasma started to be detected at 0.25 h, reach the maximum at (0.5 h Tc-hcl) and 1 h.(TC-nm) and decline at 12 hours. Following a single i.v administration a volume of distribution V2 (0.292±0.111 L/kg) in TC-nm than for TC-hcl (0.216 ± 0.183L/kg) and was slowly cleared (0.393±0.183 L.h/kg) in Tc-nm than in TC-hcl (0.415±0.311 L.h/kg). After oral administration a rapidly absorbed with significant slowly absorption half-life t1/2 _alpha (0.550±0.090 h and 0.176±0.058 h.) and elimination half-life t1/2 _beta (4.215±1.661 h. and 1.58±1.447 h.) with higher calculated Cmax of (4.215±1.661 μg/ml and 1.58±1.447 μg/ml) achieved at prolonged calculated tmax (0.759±0.149h. and 0.356±0.305 h.) in TC-nm than in TC-hcl, respectively.
The value of TC-hcl and TC-nm MIC was the same for Staph. Aureus 6538, Staph. Epidermidis12228 ,E.coli 8739 were 0.14, 0.8 and 0.12 µg , respectively, and interpreted as sensitive. Field sensitive Corynebacterium, E.coli , S. typhimurium, S. enteriditisand Staph.leutus isolates MIC value was 1.4, 8, 2, 1.6 and 2 µg for  , respectively. Tetracycline resistant2Staph.scuiri (18 and  16µg) and 2 Staph. xylosis ( 18 and 6µg).