Pharmacokinetics
oxytetracycline and tetracycline was rapidly absorbed after Fasting animal oral.The bioavailability of 60%~80%.Food or milk products will greatly reduce the absorption rate of oxytetracycline, can be reduced by 50% or more.Oxytetracycline (non persistent) after intramuscular injection.blood drug concentration in vivo.The peak time for 30min to several hours, depending on the drug injection volume and location of long-acting oxytetracycline products; and intramuscular injection to the absorption rate of drugs than non long-acting much slower.
Tetracycline can be widely distributed in the body, including the heart, kidney, lung, pleural fluid, bronchial secretions, saliva, urine, bile, phlegm, synovial fluid, pericardial fluid, aqueous and vitreous humor.Only a small amount of tetracycline and oxytetracycline in the cerebrospinal fluid.but it can not achieve the treatment level.All tetracycline antibiotics in vivo distribution in prostate and eye, and doxycycline and minocycline could enter them and most of the other tiues.Tetracycline antibiotics can also pa through the placenta,enter the fetal circulation, and can also enter breast milk.Tetracycline in volume of distribution in vivo is about: small animal 2.1L/kg, horse 1.4L/kg.Plasma protein binding rate of 10%~40% oxytetracycline.
Oxytetracycline and tetracycline mainly excreted by prototype after the glomerular filtration.Renal injury patients drug elimination rate half-life is prolonged, after continuous atreatment, drugs may accumulate in the body.Obviously, such drugs in vivo without metabolism, but can enter the gastrointestinal tract by bile or non bile pathway, and integration and fecal matter, which transforms into an inactive form.In vivo oxytetracycline\'s half-life, dog and cat 4~6h, cattle 4.3~9.7h, Mayo was 10.5h, the pig is about 6.7h, the sheep is about 3.6h.
