In vitro and in vivo release kinetics of rectal formulations with different quinine concentrations

Abstract

the aim of this work was to improve the rectal bioavailability of quinine hydrochloride from hydroxylpropylmethycellulose
(hPMc) based gels formulation.
Methods. Absorbent gel with 1,5 % of hPMc and with various quinine concentrations bases (20, 40,60
and 80 mg/g) were carried out. this gel was the object of studies of viscosity, in vitro release, rectal
bioavailability and rectal tolerance on albino rabbits.
the gels carried out were of a very low viscosity. compared to gel 20, the absolute rectal bioavailability
(f) of quinine of gel 40 increased by 8 %. however gel 20 (dt 50 of 52 min) presented a better profile of
in vitro release than gel 40 (dt 50 of 65 min). the absolute rectal bioavailability of gel 60 and 80, respectively
of 81 and 81.5 %, were lower than that of gel 40 (91.2 %). Except for the gel 80 which caused ulcers,
all the other gel presented an acceptable tolerance on the rectal rabbit mucous membrane.
Presentation of 40 mg/g was thus most effective for an optimal rectal bioavailability of quinine hydrochloride
in gel with 1,5 % of HPMC.