New insight into the clinical pharmacokinetics of cefaclor: Tissue penetration

The serum pharmacokinetic data presented are generally in agreement with th ose obtained by other authors with both the cefaclor IR (immediate release) and AF (advanced formulation) or MR (modified release) formulations. With the new sustained-release formulation, the time of peak (T-max) and mean re sidence time (MRT) values are significantly longer than those observed with the standard cefaclor IR, For the first time the penetration of the MR for mulation of cefaclor was determined both in suction blister fluid (SBF) and alveolar epithelial lining fluid (ELF). Cefaclor demonstrated a high tissu e distribution, with a high penetration index (PI) into blister fluid, whic h is at least representative of a relatively large volume of fluid-filled s paces and in part of highly vascularized tissues, SBF and ELF concentration s were higher than blood levels starting at the 4(th)-6(th) hour after dose , with longer elimination half-lives from the extravascular compartment tha n from serum. Cefaclor has a favorable pharmacokinetic profile, especially the new sustai ned-release formulation, which maintains effective concentrations for a lon ger time than the IR preparation, The MR formulation improves the kinetic p roperties of the cefaclor molecule with a prolonged MRT which allows a dail y dosage of 750 mg every 12 h.