Abstract: A pharmaceutical composition in the form of a tablet for controlled release of active ingredient(s) comprises lamivudione, zidovudine or combination of lamivudine and zidovudine or their pharmaceutically acceptable derivatives, and a mixture of hydrophilic polymers selected from the group consisting of at least one hydroxypropyl methylcellulose, at least one sodium alginate and at least one guar gum as controlled release matrix and a pharmaceutically acceptable calcium salt as a matrix stabilizer. The composition may also contain one or more of a water soluble and/or water dispersible diluent, wherein the quantities of the hydrophilic polymers, the calcium salt and water soluble and/or water dispersible diluents are such that the therapeutically effective active ingredient(s) is released at a rate suitable for once daily administration of the pharmaceutical composition. The tablets may be coated with a water soluble polymeric film coat.