Pharmacokinetics of ceftazidime

1. ceftazidime is not absorbed by oral administration. After intravenous or intramuscular injection, it is rapidly and widely distributed in body tissues and body fluids, and can be distributed in visceral tissues, skin and muscles, bones, joints, sputum, ascites, pleural effusion, amniotic fluid, cord blood, bile, uterine appendages and myocardium. It is easy to enter the placenta through the placental barrier, and can also be distributed in aqueous humor and milk. It is difficult for this product to pass through the normal blood-brain barrier. When the meninges are damaged or inflamed, it can enter the cerebrospinal fluid through the damaged meninges.

2. This product hardly undergoes metabolic biotransformation in vivo, and is mainly excreted with urine, so it is a prototype drug with high activity. Nearly 80 ~ 90% of the dose is excreted in urine within 24 hours, and less than 1% can be excreted in bile. Therefore, the urine concentration is very high and the intestinal concentration is extremely small. Normal people have no accumulation effect after repeated administration, but the drug excretion time of patients with renal insufficiency, newborns and premature infants is prolonged, and drugs can accumulate in the body.

3. The plasma concentration of this product is related to the dose, and the binding rate of serum protein is 10% ~ 17%. The plasma half-life of intramuscular injection, intravenous injection and intravenous drip is 2 hours. The plasma half-life of newborns with renal insufficiency is 2 ~ 2.5 times longer than that of healthy adults. ④ After intramuscular injection of 0.5 or 1g in healthy adults, the plasma concentration reached the peak of 22.6mg/L and 38.3mg/L within 1 ~ 1.2 hours, respectively. After intravenous injection and intravenous drip of 1.0g, the peak blood concentration of this product was 120.5mg/L and 105.7mg/L respectively.