Abstract: The invention relates to a novel diffusion-osmotic controlled drug-release pharmaceutical composition containing a one-layer tablet core including a polymeric film-coat, a therapeutically active agent and a hydrophilic polymer; if desired, a two-layer tablet core including active agent and hydrophilic polymer in the first layer thereof and a hydrophilic polymer in the second layer thereof; at least one bore on the part of film-coat in contact with the core or core layer containing the active agent; and, if desired, containing one or more bore(s) in the part thereof in contact with the second layer containing the hydrophilic polymer, which comprises an ammonium methacrylate copolymer as coating material and hydroxypropyl-methylcellulose as hydrophilic polymer. The composition according to the invention is useful for preparing controlled drug-release tablets containing as active agents e.g. .beta.-adrenergic inhibitors (e.g. propranolol) calcium-antagonists (e.g.

Abstract: This invention relates to a new and improved process for the preparation of 6,7-dichloro-1,5-dihydroimidazo[2,1-b]-quinazolin-2[3H]-one of formula ##STR1## (anagrelide), a valuable blood platelet antiaggregative compound. According to the process of the invention the compound of formula (I) is prepared by subjecting a new 2-cyanoiminoquinazoline derivative of the general formula ##STR2## wherein R stands for cyano or a group of the formula COOR.sup.1, in the latter R.sup.1 representing lower alkyl optionally carrying a phenyl substituent, to thermal cyclization in an acidic medium.The invention also relates to new 2-cyanoiminoquinazo-lines of the general formula (III) used for the production of anagrelide and to the preparation of the said compounds.The invention provides an advantageous process for the preparation of anagrelide which is devoid of the drawbacks of the hitherto known processes and renders possible the production of the compound of the formula (I) on industrial scale, too.