| abstract |
A guanidine derivative of the formula l:-n in which R 1 , R 2 , R 3 , R 4 , ring X and D are a variety of radicals defined in the specification and A is a 3-8C alkylene chain which is substituted by a hydroxy radical and into which is optionally inserted, as part of the backbone of the chain, one or two groups selected from oxygen and sulphur atoms and NH and 1-6C N-alkyl radicals; and the pharmaceutically-acceptable acid additions salts thereof. Pharmaceutical compositions and methods of manufacture are also described. The compound of the formula I is a histamine H-2 antagonist and is therefore useful in ulcer therapy. |