The present invention relates to pharmaceutical compositions of flutamide. Specifically, the invention relates to a controlled release form which is designed to provide an immediate release dose and a second delayed dose.
U.S. Pat. No. 4,329,364 discloses that flutamide is useful in treating, alleviating and palliation of androgen-caused and/or androgen-dependant conditions such as prostatic hyperplasia, for example benign prostatic hypertrophy and prostatic carcinoma.
U.S. Pat. No. 4,474,813 discloses conventional pharmaceutical preparations of flutamide adapted for systemic administration providing a therapeutic effect against prostatic carcinoma.
Flutamide which has the chemical name 2-methyl-N-[4-nitro-3-(trifluoromethyl)phenyl]propanamide, or N-isobutyryl-4-nitro-3-trifluoromethylanilide, is a nonsteroidal compound devoid of androgenic, adrenocortical, anti-estrogenic, estrogenic, progestational, and antifertility actions. This compound has proved to be a potent antiandrogen and is approved for the palliative treatment of advanced prostate cancer in man. The approved therapeutic dose is 750 mg/day of flutamide in three divided doses of 250 mg/dose. The approved product, Eulixin.RTM., is available in capsules containing 125 mg of flutamide, therefore, the patient takes two capsules three times a day. Patient compliance with the recommended dosage schedule is sometimes poor, since a large number of patients undergoing this treatment are elderly and are forgetful.
One of the objects of the present invention was to develop a controlled release oral dosage form of flutamide which would allow for twice a day use. In addition, the novel controlled release dosage form would provide comparable bioavailability when compared to the standard capsule dosage form.