[Comparison of concentration of piroxicam in blood and local site after two routes of administration].
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.ml-1) or transdermal gels 1 mg.ml-1 were given. Systematic concentration (Cs) and local concentration (C1) of the drug in each mouse were determined by HPLC method. After transdermal administration of 0.25 mg of piroxicam gels Cmax(s) = 8.06 micrograms.ml-1 and AUC(s)0-24(s) = 58.36 micrograms.h.ml-1 were obtained, whereas after oral administration of 0.026 mg.10 g-1 body weight of piroxicam suspensions Cmax(s) was 36.82 micrograms.ml-1 and AUC(s)0-24 was 155.59 micrograms.h.ml-1. The C1/Cs ratio (0.01) through oral route was far lower than the C1/Cs ratio (0.13) through transdermal route. The area under local concentration-time curve (15.85 micrograms.h.ml-1) calculated from transdermal administration was much higher than that from oral administration (1.93 micrograms.h.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.
Fang
X L
XL
Division of Biopharmaceutics, Shanghai Medical University.
Jiang
X G
XG
Zhang
Z R
ZR
Xi
N Z
NZ
D000279:Administration, Cutaneous; D000284:Administration, Oral; D000818:Animals; D001682:Biological Availability; D005260:Female; D051379:Mice; D010894:Piroxicam / Q000008:administration & dosage / Q000493:pharmacokinetics*; D011897:Random Allocation
D010894:Piroxicam