Pharmacokinetics Essay Example | Topics and Well Written Essays - 1000 words

Pharmacokinetics - Essay Example Ceftriaxone is classified as a third and fourth-generation cephalosporins. This spectrum of third and fourth-generation cephalosporins varies considerably and before administration, it is important to confirm based on culture and susceptibility testing before use. They are active against a broad range of gram-negative bacteria and moderately active against gram-positive bacteria’s. Ceftriaxone has a molecular weight of 661.59 with a chemical formula of C18H16N8Na2O7S3†¢3.5H2O. This formula has been illustrated below. The drug is a white to yellowish powder in crystalline form that is readily soluble when put in water, partly soluble in methanol and ethanol. Its PH of a 1 percent aqueous solution is 6.7. However, its color is bound to change depending on its length of storage, the concentration utilized as well as the diluent. It is provided in vials containing 10 grams of the drug to be reconstituted (Garot et al. 2011, p. 760). The drugs average plasma concentration after administration following a 30 minutes intramuscular administration of a 0.5 (350 mg/ml or 250mg/ml) or 1gram dosage and intravenous administration of 0.5, 1 and 2 grams dosage is illustrated in Table 1 below. From the illustration, it is clear that the drug is completely absorbed following intramuscular administration. The mean maximum concentration of the drug occurs between 2 to 3 hours after the drug administration. Thus following an intramuscular administration it is completely absorbed with a T  max of 2-3 hours (Blumer 1991, p. 52). It is distributed in most of the fluids in the body i.e. bones, kidneys, biliary tract, joints and lungs. 33 to 67 percent of the drug is execrated in urine as an unchanged while the rest is secreted in the bile and found in feces as inactive drug compounds. The drug elimination half-life over a 0.15 to 3 g dosage ranges from 5.8 to 8.7 hours. The drug apparent volume of distribution ranges from 5.78 to 13.5 L, a plasma clearance of 0.58 to 1.45