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Novel
buccoadhesive delivery system of hydrochlorothiazide
formulated with ethyl cellulose-hydroxypropyl
methylcellulose interpolymer complex
A. A. Attama,
P. A. Akpa*, L. E. Onugwu and G. Igwilo
Drug Delivery Research Unit, Department
of Pharmaceutics, University of Nigeria, Nsukka 410001,
Enugu State Nigeria.
*Corresponding author. E-mail:
aakpa@alumni.unav.es.
Tel: +234-42-771911. Fax: +234-42-771709.
Accepted 11 June, 2008. |
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The
buccoadhesive and in vitro release properties of patches
formulated with ethylcellulose (EC) and hydroxypropyl
methylcellulose (HPMC) interpolymer complexes of different
ratios were studied. The patches containing
hydrochlorothiazide (HCTZ) were prepared by casting and
thereafter, evaluated using the following parameters:
diameter, thickness, swelling behaviour, buccoadhesive
strength, drug content analysis and in vitro release
studies. An adapted Lecomte Du Nouy tensiometer was used to
assess the buccoadhesion of the patches on freshly excised
buccal mucosa of a pig. The release of HCTZ from the patches
was studied in phosphate buffer (pH 7.5). The result of the
study indicated that 1:2 ratio of EC and HPMC gave the
highest buccoadhesive strength. All the patches had uniform
diameters but varied thicknesses with their areas ranging
from 2.06 to 2.16 cm2. The area swelling ratio (ASR)
indicated that the patches did not swell up to two times
their initial areas, with the batch containing 3:2 ratio of
EC and HPMC possessing the highest ASR. Higuchi’s analysis
of the release mechanism indicated that the release of HCTZ
from the patches formulated with 1:1 and 2:1 ratios of EC
and HPMC predominantly occurred by a diffusional process.
This method could be used as an effective alternative
delivery system for HCTZ compared with conventional tablet
formulations.
Key words: Hydrochlorothiazide, ethylcellulose,
hydroxypropyl methylcellulose, interpolymer complex, area
swelling ratio, buccoadhesive delivery. |
