Formulation and Optimization
of Gastric Bioadhesive Tablets of Diltiazem
Hydrochloride using Central Composite Design
Saurabh Sharma1*,
Arun Nanda2 and Lalit Singh3
1Department of Pharmacy, Vivek
College of Technical Education, Bijnor, 2Department
of Pharm Sci, M D University, Rohtak, 3SRMS
CET, Bareilly, India
*For correspondence: Email:
saurabhmpharm@rediffmail.com;
Tel: +919927026893
Received: 5 September 2013
Revised accepted: 2 October 2013
Tropical Journal of
Pharmaceutical Research, December 2013;
12(6): 861-867
http://dx.doi.org/10.4314/tjpr.v12i6.1
Abstract
Purpose: To develop bioadhesive
tablets of diltiazem hydrochloride with a unique
combination of bioadhesion and drug release.
Method: Tablets were prepared by
physical blending of diltiazem hydrochloride with two
polymers, viz., carbopol and hydroxylpropyl methyl
cellulose in different ratio along with other excipients.
A 32 central composite design was employed to
optimize the formulations on the basis of phycochemical
properties, bioadhesive strength (measured as force of
detachment from gastric mucosa) and in vitro drug
release. HPMC K 4M and Carbopol 934P were taken as the
independent variables. Contour plots were drawn and
optimum formulations were selected by feasibility and
grid searches.
Results: The tablets showed excellent
bioadhesive strength which varied from 7.6 to 21 g. Both
polymers had effect on the bioadhesive strength of the
tablets and maximum bioadhesion was observed at the
highest level of both the polymers. The drug release
from the formulation varied from 79.74 to 94.54 % in 12
h. The diffusion exponent (n) of Korsmeyer-Peppas model
ranged from 0.491 to 0.658 which indicates the mechanism
of drug release was anomalous transport; the diffusion
exponent (n) increased with increase in the amount of
either polymer in the bioadhesive tablet.
Conclusion: Floating bioadhesive tablets
of diltiazem hydrochloride with good bioadhesion and
controlled release characteristics is feasible.
Keywords:
Drug delivery,
Gastroretentive, Bioadhesive, Diltiazem, Central
composite design.
