Purpose: To evaluate the effect of formulation variables on the
bioadhesion and release properties of bioadhesive cyproheptadine
hydrochloride tablets. Methods: Screening of polymers - hydroxypropyl
methylcellulose, (HPMC), sodium carboxy methyl cellulose (CMC), and
Carbopol 974p and 934p - in solution form were carried out by shear
stress and detachment force measurement,based on Taguchi model, in
order to determine their bioadhesion properties. Central composite
design (CCD) was applied to optimize the combined effects of the
polymers on release rate constant (K), diffusion coefficient (n),
regression coefficient (R2) and detachment force of a sustained release
tablet formulation of cyproheptadine hydrochloride containing also a
prompt dose of the drug. Results: The shear stress of 3 % solution of
HPMC was greater than that of an equivalent concentration of Carbopol
934P. The values of K, n, R2 and detachment force for the optimized
formulation (F0) were 0.269, 0.696, 0.964 and 0.066 Newton (N),
respectively, and showed good correlation with the predicted values,
thus confirming the practicability and validity of the model.
Conclusion: Gastric retention time can be increased for cyproheptadine
hydrochloride by formulating it as a bioadhesive tablet that enhances
the retention of the dosage form in the stomach and hence gastric
absorption of the drug