K.P.R Chowdary, Veer Reddy. K, Bhaskara Reddy Nallamilli
Modified starches are promising and having good potential as release retardants and rate controlling polymers for controlled release. The controlled release properties of modified starches, generally based on solvent-activation have been intensively investigated.
Aim: The present aimed to investigate the in vivo performance of the new polymer (Cross linked starch-urea or CLSU) in the formulation of controlled release dosage forms.
Methods: Diclofenac matrix tablets employing CLSU were prepared by gelatinizing potato starch in the presence of urea and calcium chloride. 15 mg strength of diclofenac matrix tablets (B) were formulated employing CLSU and pure drug (A) were tested for in vivo pharmacokinetic evolution. Plasma drug concentration of Diclofenac was determined by HPLC method. From the time Vs plasma concentration data various pharmacokinetic parameters such as peak concentration (Cmax), time at which peak occurred (Tmax), area under the curve (AUC), elimination rate constant (kel), biological half-life (t1/2), percent absorbed to various times and absorption rate constant (Ka) were calculated in each case as per known standard methods.
Results: The absorption rate constant (Ka) was found to be 0.152h-1 for A and 0.817 h-1 for B, and MRT was increased from 9.68 h for A to 14.05 h for B. Tmax raised to 6 h for B from 3 h for A. Based on AUC0 α the relative bioavailability of the diclofenac from CLSU was found to be 124.9% compared to diclofenac pure drug (100%).
Conclusion: Thus the results indicated that starch urea cross-linked with calcium chloride is a promising matrix former for controlled release.
