monthly administration for example an insoluble salt of the active compound such as the decanoate salt may be adapted to provide a depot preparation for intramuscular injection for preparing solid compositions such as tablets the principal active ingredient is mixed with a pharmaceutical carrier e g conventional tableting ingredients such as corn starch lactose sucrose sorbitol talc stearic acid magnesium stearate dicalcium phosphate or gums and other pharmaceutical diluents e g water to form a solid preformulation composition containing a homogeneous mixture of a compound of the present invention or a pharmaceutically acceptable salt thereof when referring to these preformulation compositions as homogeneous it is meant that the active ingredient is dispersed evenly throughout the composition so that the composition may be readily subdivided into equally effective dosage forms such as tablets pills and capsules this solid preformulation composition is then subdivided into unit dosage forms of the type described above containing from 0 1 to about 500 mg of the active ingredient of the present invention the tablets or pills of the novel composition can be coated or otherwise compounded to provide a dosage form affording the advantage of prolonged action for example the tablet or pill can comprise an inner dosage and an outer dosage component the latter being in the form of an envelope over the former the two components can be separated by an enteric layer which serves to resist disintegration in.