Formulation and Evaluation of Bioadhesive Cyproheptadine Tablets

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 (R^2) 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, R^2 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 hencegastric absorption of the drug.