Disposition of acetaminophen and indocyanine green in cystic fibrosis-knockout mice.

Drug treatment poses a therapeutic challenge in cystic fibrosis (CF) because the disposition of a number of drugs is altered in CF. Enhanced clearance of acetaminophen (APAP) and indocyanine green (ICG) have previously been reported in CF patients. The objective of the current study was to investigate if the CF-knockout mouse model (cftr(m1UNC)) shows altered pharmacokinetics similar to those seen in CF patients using the 2 model compounds APAP and ICG. Clearance (CL/F) of APAP and renal (CLR) and formation (CLf) clearance of acetaminophen glucuronide (AG) and acetaminophen sulfate (AS) were determined in CF-knockout mice following administration of APAP (50 mg/kg, intraperitoneal). CLR of AS was 19.5 and 12.9 (mL/min per kg) and CLf of AS was 10.4 and 6.7 mL/min per kg for homozygous and heterozygous males, respectively, which was significantly different between groups. CLR of AG was 6.3 and 4.8 mL/min per kg and CLf of AG was 9.6 and 8.9 mL/min per kg for homozygous and heterozygous males, respectively, although not reaching statistical significance. No significant differences were noted in either ClR or CLf of AG and AS in female CF mice. Plasma concentrations of ICG (10 mg/kg, intravenous) were determined over 0 to 15 minutes. Homozygous females showed a higher apparent volume of distribution (96 mL/kg) relative to heterozygous females (72 mL/kg). Similar to CF patients, a trend toward a lower Cmax was noted in homozygous male and female mice. However, contrary to human data, no significant differences in CL of ICG were noted. These results suggest that the CF-knockout mice have potential as a model for studying altered drug disposition in CF patients.