Transdermal compositions

A process for the preparation of an anhydrous transdermal composition comprising in a 20 to 100% lyotropic liquid crystalline arrangement:

• 5 to 15 weight % of optically active or racemic N-methyl-N-(1-phenyl-2-propyl)-2-propynylamine or N-methyl-N-{1-(4-fluorophenyl)-2-propyl}-2-propynylamine or a pharmaceutically acceptable salt thereof;
• 40 to 70% by weight of liquid polyethylene glycol;
• 10 to 20% by weight of solid polyethylene glycol;
• 2 to 30% by weight of a nonionic surface active agent;
• 2 to 20% by weight of propylene glycol, and if desired,
• 0.5 to 2% by weight of a polymer, the a value of which is greater than 0.6, and
• optionally, in an amount needed up to 100% an emulsifying agent, which comprises the step of:
• (a) preparing a mixture comprising 40 to 70% by weight of the liquid polyethylene glycol, 10 to 20% by weight of the solid polyethylene glycol, 2 to 30% by weight of the non-ionic surface active agent, and 2 to 20% by weight of the propylene glycol;
• (b) inoculating the mixture formed in step (a) with 5 to 15% by weight of the optically active or racemic N-methyl-N-(1-phenyl-2-propyl)-2-propynylamine or N-methyl-N-{1-(4-fluorophenyl)-2-propyl}-2-propynylamine or a pharmaceutically acceptable salt thereof dissolved in warm polyethylene glycol;
• and
• (c) cooling the inoculated mixture and optionally adding thereto 0.5 to 2% by weight of the polymer, the a value of which is greater than 0.6, to obtain the lyotropic liquid crystalline composition, and adding optionally, in an amount needed up to an emulsifying agent.