R. Espinoza et al., Influence of admired citric acid on the release profile of pelanserin hydrochloride from HPMC matrix tablets, INT J PHARM, 201(2), 2000, pp. 165-173
Pelanserin is a weakly basic experimental drug with a short half-life and a
prolonged release formulation was developed using hydroxypropyl methylcell
ulose (HPMC) and citric acid to set up a system bringing about gradual rele
ase of this drug. For this purpose powder mixtures were wet granulated with
water and compressed with a hydraulic press at 55 MPa. Dissolution studies
were made using 900 mi HCl 0.1 N, the first 3 h, and phosphate buffer pH 7
.4, h 3-8. Dissolution curves were described by M-t/M-inf= kt(n), applied s
eparately for each dissolution medium. The dissolution mechanism involved a
coupled diffusion/relaxation with a trend favoring the diffusion mechanism
with increasing citric acid concentrations. Increasing concentrations of c
itric acid produced increasing values of the kinetic constants, in a cubic
relationship. Higher HPMC proportions produced slower dissolution rates but
with a citric acid compensating more clearly a decreased solubility of pel
anserin at pH 7.4. Individually calculated dissolution curves showed experi
mental 8 h pelanserin dissolution in a ran ge of 65-99% for matrices with 1
00 mg HPMC/tab., while those with 200 mg HPMC/tab. were in the range 57-73%
. (C) 2000 Elsevier Science B.V. All rights reserved.