Formulation development of stronger and quick disintegrating tablets: a crucial effect of chitin.

A well known superdisintegrant like croscarmellose sodium or crospovidone loses their quick disintegration property when compressed at more than 4 kg tablet crushing strength (TCS). Therefore, the objective of the present work was to develop a disintegrating system that could be used for preparing fast disintegrating tablets (FDTs) of highly water soluble drug, metoclopramide, without compromising on the mechanical strength, irrespective of the TCS used for compressing the granules. For this purpose disintegrating system consisting of chitosan-alginate (CTN-ALG) complex (1:1): glycine and chitin was developed. The results revealed that when CTN-ALG and glycine were mixed in the ratio of 30:70, the granules exhibited a minimum water sorption time and maximum effective pore radius (R(eff.p)). The addition of chitin (5-10% w/w) into this mixture further enhanced the R(eff.p). Further, increase in the concentration of chitin from 10% to 20% w/w did not produce any significant effect (p>0.05) on the R(eff.p). The FDTs prepared by using CTN-ALG:glycine (30:70) and chitin exhibited increased porosity and lower disintegration time (DT). Further, chitin was found to neutralize the effect of TCS on DT of FDTs. This property of chitin was also observed in FDTs prepared by using croscarmellose sodium (5% w/w) or crospovidone (5% w/w). The reduction in DT of FDTs by chitin was also observed in tablets prepared without the drug. Hence, the effect was not influenced by the solubility component present in the tablets. Overall, the results suggested incorporation of chitin (5-10% w/w) while preparing FDTs of metoclopramide to enhanced the disintegration without compromising their mechanical strength of the tablets.