Transdermal system for simultaneous delivery of a number of acti

Details Transdermal system for simultaneous delivery of a number of acti Transdermal system for simultaneous delivery of a number of acti

1997-06-11

1999-07-06

Brouillette, D. Gabrielle

Drug, bio-affecting and body treating compositions

Preparations characterized by special physical form

Web, sheet or filament bases; compositions of bandages; or...

424449, A61F 1302

Patent

active

059194774

DESCRIPTION:

BRIEF SUMMARY
FIELD OF THE INVENTION

The present invention relates to systems for the transdermal delivery of a number of active principles simultaneously, said systems being designed so as to facilitate adjustment of the delivered doses of one or more active principles and reduce the surface area of such systems in order to improve safety and comfort when used by the patient.


PRIOR ART

There are numerous devices currently in existence for the transdermal delivery of an active principle.
The composition of these devices is defined for the purpose of (i) ensuring a good physicochemical stability of the active principle over time, and (ii) obtaining an optimal transdermal absorption flux per unit surface area. Thus the dose of active principle delivered in the course of a treatment is mainly determined by the surface area of the device applied to the skin.
Now, this surface area must not be so large as to cause physical discomfort when the device is used and produce a device whose size and esthetic appearance would rule out its use altogether. The device must also have good adhesion and cohesion properties, making it easy, pleasant and discreet to apply when used.
Thus devices containing a single active principle are produced at the present time and satisfy these demands, i.e. they are effective, small and comfortable and neither creep nor become detached during use.
On the other hand, the production of such efficient systems for the delivery of two active principles, or even more than two active principles, still presents numerous problems which become increasingly difficult to solve as the number of active principles to be delivered increases.
A first known technical solution among those envisaged in the prior art involves transdermal systems which consist of a single device containing all the active principles mixed together. Such systems are described for example in patent documents EP-A-0 285 563, WO-A-92/07589, WO-A-92/07590 and WO-A-94/06383. Although these systems have the advantage of being small, they prove generally very complex, if not impossible, to perfect.
In fact, by virtue of their nature and their physicochemical properties, the active principles behave in different ways towards the corneal layer and often have important influences on the composition of the device.
Because the skin has different permeabilities to the active principles, each active principle has a different absorption flux. It therefore proves virtually impossible to obtain the desired therapeutic dose of each active principle to be delivered by simultaneously using the same absorption area and the same formulation.
Furthermore, if it is necessary to readjust the delivered dose of at least one of the active principles during clinical development, it is impossible to modify the delivered dose of this active principle independently of those of the other active principles without having to change the formulation of the other components.
Similarly, it is also common for one and the same system for the transdermal delivery of a number of active principles to be used for delivering several dosages of these active principles according to the patients or pathological conditions treated.
This will be done by choosing different surface areas of said system on account of the fact that the dose of active principle delivered will be proportional to the surface area applied to the skin.
In the case of such a system for the delivery of a number of active principles where different posologies are required, if at least two active principles do not remain in the same dose ratio for all the chosen posologies, or if one active principle is delivered at a fixed dose, it will be impossible to obtain the different desired posologies by varying the surface area of the device, since in this case the doses of each active principle vary simultaneously as a function of the surface area and in constant dose ratios.
In both the above cases, therefore, the benefit of the work already put in is lost and comfortable systems with good fluxes and good physical properti

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patent: 4911707 (1990-03-01), Heiber
patent: 5064422 (1991-11-01), Wick
patent: 5071656 (1991-12-01), Lee
patent: 5128137 (1992-07-01), Muller
patent: 5350581 (1994-09-01), Kochinke
patent: 5538736 (1996-07-01), Hoffmann

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