Ciprofloxacin ADME

Cipro is highly soluble in aqeuous media below pH 5 and above pH 10. About 60 to 80 percent are taken up by the body. The main absorption site of ciprofloxacin is the upper GI tract, up to the jejunum (Harder et al, 1990; summarized in Olivera et al, 2011). In the context of the Biopharmaceutics Classification System (BCS) Cipro is "not highly soluble", and "not highly permeable". It is classified as BCS class 2, 3, and 4, and uptake and efflux transporters have a big effect on its absorption and excretion. BCS class 4 drugs are primarily excreted unchanged via the biliary or renal routes.

Very high concentrations of Cipro with respect to plasma concentrations are seen in kidney and gall bladder; high concentrations are also found in liver, prostatic tissue, and lung. The main excretion routes for unchanged Cipro are renal (about 65% of plasma amount) and intestinal (about 10%) (Rohwedder et al, 1990; Viell et al, 1992; reviewed by Sörgel, 1989). The intestinal figure includes excretion through epithelial GI cells, and through hepatic cells and the bile duct. The rest of plasma Cipro (10 to 20%) is metabolised, with the major species recovered from urine being oxociprofloxacin and, in faeces, sulfociprofloxacin. Both account for about five per cent each of total excretion (reviewed by Campoli-Richards et al, 1988).