Bioavailability of Nalidixic acid from uncoated tablets in humans--Part II: Bioavailability in beagles and its correlation with bioavailability in humans and in vitro dissolution rates

The bioavailability of nalidixic acid in beagles was determined using the same tablet formulations previously tested on humans and was compared with bioavailability in humans and with in vitro dissolution rates. The beagle bioavailability test provided lower power in all of the bioavailability parameters than did the human test. Tmax of the tablets did not greatly differ in beagles, although in humans a wide variation of Tmax was seen. A linearity between Cmax and AUC0-infinity was observed in beagles, but Tmax did not show a linearity with Cmax or AUC in dogs, which is quite different from the relations observed in humans. The rank order of tablets according to Cmax was exactly the same between humans and beagles. AUC also showed the same rank order between humans and beagles except for on tablet with a poor disintegrating ability. A significant correlation between human and beagle Cmax values was obtained (r = 0.8952; p less than 0.05), but not between human and beagle AUC and Tmax values.