Transdermal therapeutic system exhibiting an increased active substance flow and process for the production thereof

In a process for the production of a transdermal therapeutic system exhibiting a layered structure, consisting of a backing layer (11) which is substantially impermeable to active substances, a matrix (12) comprising the active substance, and a layer (13) controlling the access of cutaneous liquid, in which the matrix (12) consists of a material (15) which is permeable to water vapour, but substantially water-insoluble and free of active substances, in which islands (14) are distributed which consist of a solid solution of pharmaceutical in a water-soluble or water-swellable base material, the proportion of islands being between 0.5 and 70%, the matrix being activatable by cutaneous liquid, the step which comprises forming the islands (14, 24) by precipitation from a solution of the active substance and the water-soluble or water-swellable base material by means of a suitable precipitation agent in which the water-soluble or water-swellable base material is substantially insoluble.

In a process for the production of a transdermal therapeutic system exhibiting a layered structure, consisting of a backing layer (11) which is substantially impermeable to active substances, a matrix (12) comprising the active substance and a layer (13) controlling the access of cutaneous liquid, in which the matrix (12) consists of a material (15) which is permeable to water vapour, but substantially water-insoluble and free of active substances in which islands (14) are distributed which consists of a solid solution of pharmaceutical in a water-soluble or water-swellable base material the proportion of islands being between 0.5 and 70%, the matrix being activatable by cutaneous liquid which comprises loading the islands (14, 24) with active substance by means of solid-liquid absorption in a suspension of unloaded islands in a suitable volatile solvent comprising the active substance in dissolved form.

In a process for the production of a transdermal therapeutic system exhibiting a layered structure comprising a backing layer (11) which is substantially impermeable to active substances, a matrix layer (12) containing the active substance in an activatable form, and a layer (13) controlling the access of cutaneous liquid, wherein said matrix layer (12) comprises a material (15) which is permeable to water vapour, but substantially water-insoluble and free of active substances, in which islands (14) are distributed which consist of a solid solution of pharmaceutical in a water-soluble or water-swellable base material, the proportion of said islands (14) to the mass of said matrix layer (12) lying between 0.5 to 70% said matrix layer being activatable by cutaneous liquid, the step which comprises spray drying a solution of the active substance and the water-soluble and water-swellable base material in a suitable volatile solvent and effecting the spray-drying to yield a particle size of at most 20 .mu.m.