[Improving bioavailability of naftopidil by using bioadhesion in dogs].
OBJECTIVE
To prepare naftopidil bioadhesive sustained-release capsule and study their pharmacokinetics and relative bioavailability in the dog.


METHODS
Bioadhesive polymers such as hydroxypropyl methylcellulse (HPMC) and Carbopol 934 (CP 934) were used in capsule prescriptions. Naftopidil capsule and two formulations of bioadhesive sustained-release capsules (I and II) were given to five healthy male dogs in a cross-over test. The naftopidil concentrations in plasma were determined by a newly developed HPLC method and the pharmacokinetic parameters as well as the relative bioavailability were measured.


RESULTS
The C0-->infinity, Cmax and Tmax of naftopidil capsule was (3728 +/- 573) h.ng.mL-1, (697 +/- 94) ng.mL-1 and (1.2 +/- 0.5) h. These parameters of bioadhesive sustained-release capsule I and II, respectively, were (5518 +/- 391) h.ng.mL-1 and (5636 +/- 427) h.ng.mL-1; (468 +/- 61) ng.mL-1 and (512 +/- 72) ng.mL-1; both (4.0 +/- 0.7) h. Results from statistics showed that there were significant difference between bioadhesive formulations and the non-bioadhesive one in C0-->infinity, Cmax and Tmax. The bioadhesive formulations and the non-bioadhesive one were not bioequivalent, the relative bioavailability of the two bioadhesive sustained-release capsules were respectively 150% +/- 14% and 154% +/- 23% when compared with the non-bioadhesive capsule.


CONCLUSIONS
It is much improving bioavailability of naftopidil by using bioadhesion.
Ding
J S
JS
Second Affiliated Hospital of Hu'nan Medical University, Changsha 410011, China. dingjs2001@yeah.net
Jiang
X H
XH
Yuan
M
M
D000179:Acrylates / Q000737:chemistry; D000317:Adrenergic alpha-Antagonists / Q000008:administration & dosage / Q000493:pharmacokinetics*; D000818:Animals; D000959:Antihypertensive Agents / Q000008:administration & dosage / Q000493:pharmacokinetics*; D001682:Biological Availability; D002214:Capsules; D002626:Chemistry, Pharmaceutical; D004285:Dogs; D004337:Drug Carriers; D016503:Drug Delivery Systems; D007785:Lactose / Q000031:analogs & derivatives*; D008297:Male; D008747:Methylcellulose / Q000031:analogs & derivatives*; D009281:Naphthalenes / Q000008:administration & dosage / Q000493:pharmacokinetics*; D010078:Oxazines; D010879:Piperazines / Q000008:administration & dosage / Q000493:pharmacokinetics*; D051381:Rats
D000179:Acrylates; D000317:Adrenergic alpha-Antagonists; D000959:Antihypertensive Agents; D002214:Capsules; D004337:Drug Carriers; D009281:Naphthalenes; D010078:Oxazines; D010879:Piperazines; D008747:Methylcellulose; C071191:MK 458; D007785:Lactose; C453622:carbopol 934P; C064357:naftopidil