TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Component: The base is potassium hydroxide or sodium hydroxide.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Method: The memantine hydrochloride is synthesized by mixing nitrile derivative and organic acid, dripping concentrated sulfuric acid while cooling in an ice bath and controlling the temperature at 5-40 degrees C, heating at 30-70 degrees C, dripping halogenated dimethyladamantane, heating at 30-70 degrees C for 12-24 hours while stirring, cooling to room temperature, adding water, separating formed white crystal, filtering, washing the filter cake, vacuum-drying to obtain a 1-acetamido-3,5-dimethyladamantane white crystal, adding alcohol, base and water to the crystal, heating at 100-170 degrees C while stirring in the presence of nitrogen for 5-12 hours, cooling to room temperature, adding water, extracting using chloroform, washing formed organic phase with saturated sodium chloride solution, drying using anhydrous sodium sulfate, performing a reduced pressure concentration, adding absolute ethyl alcohol, charging a hydrogen chloride gas to salify, reflux heating to dissolve the crystal, cooling to room temperature, adding ethyl ether, freeze-drying overnight, filtering, washing the filter cake with ethyl ether, and vacuum drying. Preferred Components: The halogenated dimethyladamantane is 1-fluoro-3,5-dimethyladamantane, 1-chloro-3,5-dimethyladamantane, 1-bromo-3,5-dimethyladamantane or 1-iodo-3,5-dimethyladamantane. The organic acid is formic acid, acetic acid, oxalic acid, propionic acid, acrylic acid, butyric acid, isobutyric acid, pinalic acid, isopinalic acid, tert-pinalic acid, 2-methyl butyric acid, hexanoic acid, 2-ethyl butyric acid, heptylic acid, octanoic acid, 2-ethyl hexanoic acid, myristic acid or oleic acid. The nitrile derivative is acetonitrile, propionitrile, butanedinitrile, butyronitrile, isobutyronitrile, butylcyanide, benzonitrile, benzyl cyanide or adiponitrile. The alcohol is n-butyl alcohol, ethanediol, diglycol or glycerol. The weight ratio of halogenated dimethyladamantane to the organic acid is 1:0.5-100.