the problem underlying the invention is solved by a pharmaceutical composition for systemic transdermal administration that comprises an active loratidine metabolite as active ingredient . the antihistaminic effect of the active loratidine metabolite can be exploited for that pharmaceutical composition . a loratidine metabolite can be obtained from irotec laboratories ( county cork , ireland ) and has the following formula : according to the invention , the pharmaceutical composition can be provided in the form of a customary liquid or solid form of systemic transdermal administration . for the relevant prior art , see , for example , de - a - 3 212 053 , gb - a - 2 098 865 , remington &# 39 ; s pharmaceutical sciences , 16th edition , mack - verlag , and sucker , fuchs & amp ; spieser , pharmazeutische technologie , 1st edition , springer - verlag . the pharmaceutical composition according to the invention is customarily in the form of a viscous liquid , an ointment , a composition having a reservoir or a composition having a matrix . for example , the active loratidine metabolite may be present in a reservoir or matrix which are provided in the form of a gel or a polymer , for example in the form of a polymer according to ep - a - 0 155 229 . according to a special embodiment , the pharmaceutical composition according to the invention may have a transdermal patch structure . according to the invention , the patch structure can be provided by an acrylate - based matrix formed in customary manner on a carrier layer that is impermeable to water , it being possible to provide additionally a removable cover layer that protects the matrix . according to the invention , the material of the matrix may be a non - swellable acrylate polymer , for example durotack 280 - 2416 ( delft national chemie , zotphen , netherlands ). the invention is explained hereinafter in greater detail by way of example . a diffusion test is carried out in vitro according to franz in j . invest . dermatol ., 64 ( 1975 ) 194 - 195 and gb - a - 2 098 865 . for the test , the active loratidine metabolite is applied to one side of an isolated intact segment of mouse skin having a surface area of 2 . 5 cm 2 . the other side of the skin segment is placed in contact with a 0 . 9 % sodium chloride solution additionally containing 0 . 05 % sodium azide . the amount of active ingredient that passes into the salt solution is monitored in customary manner by hplc ( hp liquid chromatography ). details are given below . there is provided a transdermal therapeutic system of the reservoir type . for that purpose , a cover foil of 15 μm thick polyester material is used which may be provided with a skin - coloured coating or may be transparent . the cover foil is heat - moulded onto a laminate that consists of a microporous membrane , a self - adhesive contact adhesive from the group of acrylates , silicones and polyisobutylene with a tackifying resin , and a protective foil . the microporous membrane may be of the msx 115 4p type may contain 28 % eva ( ethylene vinyl acetate ). the protective foil may be a polyester material , siliconised on one side , of 100 μm layer thickness . a cavity is left between the cover foil and the microporous membrane , which is filled with a saturated solution of the loratidine metabolite in a propylene gycol / water mixture ( 1 : 1 ). the above - mentioned starting materials are mixed to form a clear solution . the solution is applied to a siliconised foil or paper to produce a content per surface area of 100 g / m 2 . a transparent polypropylene or polyester foil is laminated onto the dried matrix . the finished patches are punched out of the laminate in sizes of from 10 cm 2 ( corresponding to 2 mg of active ingredient ) to 40 cm 2 ( corresponding to 8 mg of active ingredient ).
a transdermal patch contains an active loratidine metabolite contained with polyacrylate polymer matrix . the transdermal patch provides pharmaceutically useful transdermal flux rates over time .