Controlled release powder and process for its preparation

A controlled release powder containing discrete micro-particles for use in edible, pharmaceutical and other controlled release compositions, said powder comprising particles containing an active ingredient in intimate admixture with at least one non-toxic polymer, wherein said polymer substantially but not entirely coats the active ingredient, each of said particles being in the form of a micromatrix with the active ingredient uniformly distributed throughout the matrix, said particles having an average size of from 0.1 to 125 .mu.m, and a dissolution rate of active ingredient from said particles which is substantially proportional to the square root of time, said active ingredient selected from the group consisting of:

• metoclopramide bromide, propantheline bromide, aluminium trisilicate, aluminum hydroxide, cimetidine, phenylbutazone, indomethacin, naproxen, ibuprofen, flurbiprofen, diclofenac, dexamethasone, prednisone, glyceryl trinitrate, isosorbide dinitrate, pentaerythritol tetranitrate, soloctidilum, vincamine, naftidrofuryl oxalate, co-dergocrine mesylate, cyclandelate, papaverine, nictoninic acid, erythromycin stearate, cephalexin, nalidixic acid, tetracycline hydrochloride, ampicillin, flucloxacillin sodium, hexamine mandelate, hexamine hippurate, flurazepam, diazepan, temazepam, amitryptyline, doxepin, lithium carbonate, lithium sulfate, chlorpromazine, thioridazine, trifluperazine, fluphenazine, piperothiazine, haloperidol, maprotiline hydrochloride, imipramine, desmethylimipramine, methylphenidate, ephedrine, epinephrine, isoproterenol, amphetamine sulfate, amphetamine hydrochloride, diphenhydramine, diphenylpyraline, chlorpheniramine, brompheniramine, bisacodyl, magnesium hydroxide, dioctyl sodium sulfosuccinate, ascorbic acid, alpha tocopherol, thiamine, pyridoxine, dicyclomine, diphenoxylate, verapamil, nifedipine, diltiazem, procainamide, disopyramide, bretylium tosylate, quinidine sulfate, quinidine gluconate, propranolol hydrochloride, guanethidine monosulphate, methyldopa, oxprenolol hydrochloride, captopril, hydralazine, ergotamine, epsilon aminocaproic acid, protamine sulfate, acetylsalicylic acid, acetaminophen, codeine phosphate, codeine sulfate, oxycodone, dihydrocodeine tartrate, oxycodeinone, morphine, heroin, nalbuphine, butorphanol tartrate, pentazocine hydrochloride, cyclazacine, pethidine, buprenorphine, scopolamine, mefenamic acid, phenytoin sodium, sodium valproate, dantrolene sodium, tolbutamide, disbenase glucagon, insulin, triiodothyronine, thyroxine and propylthiouracil, furosemide, chlorthalidone, hydrochlorthiazide, spironolactone, triamterene, ritodrine, appetite fenfluramine hydrochloride, phentermine and diethylproprion hydrochloride, aminophylline, theophylline, salbutamol, orciprenaline sulphate, terbutaline sulphate, guaiphenesin, dextromethorphan, noscapine, carbocisteine, cetylpyridinium chloride, tyrothricin, chlorhexidine, phenylpropanolamine, pseudoephedrine, dichloralphenazone, nitrazepam, promethazine theoclate, ferrous sulfate, folic acid and calcium gluconate, sulphinpyrazone, allopurinol and probenecid.