Appropriate additives in such a tablet may comprise diluents such as calcium carbonate, magnesium carbonate, dicalcium phosphate or mixtures thereof, binders such as hydroxypropyl-methylcellulose, hydroxypropylcellulose, polyvinylpyrrolidone, pregelatinised starch or gum acacia or mixtures thereof, disintegrants such as cross-linked polyvinylpyrrolidone, sodium starch glycollate, croscarmellose so