Comparison of concentration of piroxicam in blood and local site after two routes of administration
Fang, X.L.; Jiang, X.G.; Zhang, Z.R.; Xi, N.Z.
Yao Xue Xue Bao 30(3): 226-229
1995
ISSN/ISBN: 0513-4870 PMID: 7639082 Document Number: 442782
The systematic and local concentrations of piroxicam after oral and transdermal administration were determined and compared. Mice were randomly grouped, and oral suspensions (0.72 mg cntdot ml-1) or transdermal gels 1 mg cntdot ml-1 were given. Systematic concentration (C-s) and local concentration (C-l) of the drug in each mouse were determined by HPLC method. After transdermal administration of 0.25 mg of piroxicam gels C-max(s) = 8.06 mu-g cntdot ml-1 and AUC-(s)-0-24 = 58.36 mu-g cntdot h cntdot ml-1 were obtained, whereas after oral administration of 0.026 mg cntdot 10 g-1 body weight of piroxicam suspensions C-max(s) was 36.82 mu-g cntdot ml-1 and AUC-(s0-0-24 was 155.59 mu-g cntdot h cntdot ml-1. The C-l/C-s ratio (0.01) through oral route was far lower than the C-l/C-s ratio (0.13) through transdermal route. The area under local concentration-time curve (15.85 mu-g cntdot h cntdot ml-1) calculated from transdermal administration was much higher than that from oral administration (1.93 mu-g cntdot h cntdot ml-1). So, it seems to be unreasonable that only serum concentration is taken as a criterion for bioavailability test of piroxicam for local dosage forms, the local drug concentration should also be investigated and evaluated.