Abstract: A compound of general formula I ##STR1## wherein n is 1 or 2; R.sub.1 and R.sub.2 are each independently hydrogen, hydroxy, substituted or unsubstituted C.sub.1-4 alkyl, substituted or unsubstituted C.sub.1-4 alkoxy or halogeno;R.sub.5 is hydrogen, substituted or unsubstituted C.sub.1-4 alkyl, amino or NR.sub.6 R.sub.7 ;R.sub.3, R.sub.4, R.sub.6 and R.sub.7 are each independently hydrogen or (CH.sub.2).sub.m --[NH(CH.sub.2).sub.x ].sub.y --NHR.sub.11 wherein m is from 0-5, y is from 0-5 and each x is independently from 1-5 and R.sub.11 is hydrogen or C(NH)NH.sub.2 ;provided that when R.sub.3 and R.sub.4 are both hydrogen, R.sub.5 is amino or NR.sub.6 R.sub.7 ; pharmaceutically acceptable salts and optically active isomers thereof.

Abstract: Patients suffering from Parkinson's disease are treated by administering a composition which contains an active ingredient and a pharmaceutically acceptable carrier. The active ingredient comprises L-DOPA ethyl ester in an amount which is at least 97% by weight of the active ingredient and L-DOPA in an amount which is less than 1% by weight of the active ingredient.

Abstract: A composition which comprises a pharmaceutically acceptable carrier and an active ingredient, such active ingredient comprising L-DOPA ethyl ester derived from its crystaline form in an amount which is at least 97%, by weight, of the active ingredient, and L-DOPA in an amount which is less than 1% by weight of such active ingredient is provided by this invention. This invention also provides a process for preparing such a composition. Further, this invention provides a method of treating a patient suffering from Parkinson's disease which comprises administering to a patient a pharmaceutical composition comprising a therapeutically effective amount of L-DOPA ethyl ester derived from its crystaline form and a pharmaceutically acceptable carrier.

Abstract: A composition which comprises a pharmaceutically acceptable carrier and an active ingredient, such active ingredient comprising L-DOPA ethyl ester in an amount which is at least 97%, by weight, of the active ingredient, and L-DOPA in an amount which is less than 1% by weight of such active ingredient is provided by this invention. This invention also provides a process for preparing such a composition. Further, this invention provides a method of treating a patient suffering from Parkinson's disease which comprises administering to a patient a pharmaceutical composition comprising a therapeutically effective amount of L-DOPA ethyl ester and a pharmaceutically acceptable carrier.