The present invention relates to a process for the preparation of regulated release solid pharmaceutical compositions comprising 4-(2'-nitro-phenyl)-2,6-dimethyl-3,5-dimethoxycarbonyl-1,4-dihydro-pyr idine (referred to further on as "nifedipine") as active ingredient which comprises admixing a solution or solutions of 1 part by weight of nifedipine, 0.1-1.5 parts by weight of one or more hydrophilizing agent(s) and 0.05-1.5 parts by weight of one or more retarding agent(s) formed with one or mor...

Compositions, e.g. soft gelatin capsules. contain a light-sensitive active ingredient optionally sparingly soluble in water, e.g. nifedipine and also contain a vegetable dye. The dye ensures reliable light protection during manufacturing operations and improves the solubility of nifedipine in certain carriers. The dye may be included also in the capsule wall and is e.g. chlorophyll, caramel, saffron yellow or beetroot dye.