Results: Eight formulations were compared the drug release with the reference Ceclor® SR tablet of Lilly Suzhou Pharmaceutical Co, Ltd Formulation 8 showed the equivalence of drug release percentages with the reference tablet (18, 70; 36, 40; 96, 20 after 30, 60, 240 minutes versus 16, 54; 33, 87; 92, 96; respectively) and fitted to the specification of USP 29.