Abstract: This invention relates to a pharmaceutical dosage unit composition consisting essentially of a gelatin capsule containing (1) a disintegrating core comprising clonidine, said disintegrating core having a readily water-soluble coating, and (2) a plurality of non-disintegrating cores comprising clonidine, said non-disintegrating cores having a coating consisting of from 20 to 90 percent by weight of a water-insoluble film former and from 10 to 80 percent by weight of a water-soluble polymer, the diameter of each of the disintegrating and non-disintegrating cores being at least about 5 mm.

Abstract: A pharmaceutical dosage unit retard form having a constant, pH-independent release rate of active ingredient, consisting of a core comprising an active ingredient, and a semi-permeable diffusion coating over the core, where the coating consists of a water-insoluble film-former, a water-soluble polymer and eventually an acid-insoluble polymer incorporated therein.

Abstract: A pharmaceutical dosage unit retard form having a constant, pH-independent release rate of active ingredient, consisting of a core comprising an active ingredient, and a semi-permeable diffusion coating over the core, were the coating consists of a water-insoluble film-former, a water-soluble polymer and eventually an acid-insoluble polymer incorporated therein.

Abstract: Therapeutic system in the form of a skin patch that administers clonidine transdermally in an initial priming dose of 10 to 300 mcg/cm.sup.2 of skin that brings the concentration of clonidine in the blood to a level sufficient to elicit alpha-adrenergic stimulation without intolerable side effects, followed by a substantially constant continuous dosage in the range of 0.1 to 100 mcg/hr that maintains said level. The system is a four-layer laminate of, from the top: a protective backing; a gelled, mineral oil-polyisobutene-clonidine reservoir lamina that is the source of the clonidine for the continuous constant dosage; a microporous membrane that controls the constant dosage rate; and a gelled, mineral oil-polyisobutene-clonidine contact adhesive layer that is the source of the clonidine for the priming dose and the means by which the system is attached to the skin.