OCD and depression. 25 is double?

I am b.tech student.My psychiatrist prescribe me one tablet of psyvoxin 50mg (fluvoxamine maleate) in morning and half tablet of syconil 25mg(clomipramine hydrochloride 25) with one tablet of psyvoxin 50mg in night. In these day I have changed my state.Due to lockdown I get stuck here.My father could not even send out medicine to me due to lockdown. So I went to medical hall near me. There I found first medicine psyvoxin 50 mg but second medicine was not available there. Chemist said to me that you can use clofranil 25 mg (Clomipramine 25 mg) which will work same as syconil 25 mg. But when I take clofranil 25mg I do not feel well whereas I know both medicine have same salt (Clomipramine 25) but why I feel difference in clofranil 25 and syconil 25 althought both have same salt ??? On further research I found that Syconil 25mg expires after 23 month from it's manufacturing date whereas Clofranil 25 expires after 47 months from it's manufacturing date.Why life of clofranil 25 is double??