Effect of Ca+2 ion on the release of diltiazem hydrochloride from matrix tablets of carboxymethyl xanthan gum graft polyacrylamide

•The effect of Ca2+ ion on CMXG-g-PAAm for the drug release was investigated.•Tablets prepared by wet granulation control the drug release upto 8h.•The drug transport mechanism is diffusion and erosion from CMXG-g-PAAm matrix. The effect of Ca2+ ion cross-linker on acryalamide grafted carboxymethyl xanthan gum (CMXG-g-PAAm) on the drug release was investigated. Previously, CMXG was synthesized from XG and further grafted to CMXG-g-PAAm to retard the drug release. Once the CaCl2 solution is added to CMXG-g-PAAm, Ca2+ considerably affected the drug release mechanism mainly by diffusion and erosion. In order to validate the grafted polymer, tablets were prepared using wet granulation and dry granulation methods It has been noticed that the tablets prepared by wet granulation successfully controls the release of the drug over an extended period of time. Moreover, the release profile was aligned to Korsmeyer–Peppas equation and exhibited the drug transport mechanism via diffusion and erosion.