Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Web – sheet or filament bases; compositions of bandages; or...
Reexamination Certificate
1999-11-10
2002-02-19
Page, Thurman K. (Department: 1615)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Web, sheet or filament bases; compositions of bandages; or...
C424S449000
Reexamination Certificate
active
06348210
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to methods for transdermal drug administration. More particularly, but without limitation thereto, this invention provides a greater degree of freedom in transdermal drug delivery regimens whereby transdermal drug delivery devices may be removed and subsequently reapplied to the same or other areas of non-scrotal skin.
BACKGROUND OF THE INVENTION
The transdermal route of parenteral drug delivery provides many advantages over other administrative routes. Transdermal devices for delivering a wide variety of drugs or other beneficial agents are described in U.S. Pat. Nos. 3,598,122; 3,598,123; 3,731,683; 3,797,494; 4,031,894; 4,201,211; 4,286,592; 4,314,557; 4,379,454; 4,435,180; 4,559,222; 4,568,343; 4,588,580; 4,645,502; 4,698,062; 4,704,282; 4,725,272; 4,725,439; 4,781,924; 4,788,062; 4,816,258; 4,849,226; 4,867,982; 4,904,475; 4,908,027; 4,917,895; 4,938,759; 4,943,435; 5,004,610; 5,411,740;5,635,203, and 5,827,530 which are hereby incorporated in their entirety by reference.
One problem associated with many adhesive transdermal drug delivery devices of the prior art is that they often loose their adhesive properties and loosen or fall off before the predetermined drug administration period was completed. To deal with this problem, some products were sold with adhesive overlays that could be applied on top of the device and extending beyond its original borders to keep the device in place for the remainder of the administration period. Another common approach to resolution of this problem was to use adhesives which were highly aggressive, i.e., as close to being painful to remove as possible without actually being too painful. Removal of such systems resulted in damage to the adhesive surface which made them unsuitable for reapplication.
On the other end of the spectrum, transdermal delivery devices such as those disclosed in U.S. Pat. Nos. 4,704,282; 4,725,439 and 4,867,982 noted above have been designed to be applied to sensitive skin sites such as the scrotum or breast. These devices have non-adhesive skin contacting surfaces that have a low level of tack in order to allow them to non-adhesively cling to the skin. Testoderm® transdermal testosterone represents this type of product and users were instructed that it could be removed while showering or swimming, for example, and then replaced. An improved version of Testoderm®, Testoderm® with adhesive, had thin stripes of polyisobutylene adhesive applied to about 12% of the surface of the device to assist in maintaining the device on the scrotum and this product could also be removed and replaced in the same manner as the original Testoderm® product. Neither of these products, however, could be used on non-scrotal skin.
Another attempt to overcome the re-adhesion problems is disclosed in U.S. Pat. No.4,911,916, hereby incorporated in its entirety by reference. The device disclosed therein includes a means to restore the adhesiveness of the skin contacting surface of the device after removal from the skin. This was accomplished by adding a sufficient amount of the pressure sensitive adhesive to the drug reservoir whereby any adhesive left on the surface of the skin upon removal of the device would be replaced by adhesive diffusing from the drug reservoir to the skin contacting surface such that the device could then be replaced or repositioned on the skin without significant loss of adhesion.
The ability to remove and to reapply a transdermal drug delivery device makes it more convenient to extend the functional life of the device as shown, for example, in U.S. Pat. No. 5,827,530. Instead of being refilled while still on the patient, the device can be removed, refilled and replaced.
Various adhesives are known to the art for maintaining transdermal drug delivery devices in drug transmitting relationship with the skin or mucosa as disclosed in the above patents. Such adhesives may be formed from both cross-linked and non-crosslinked polymers including, for example, acrylates, silicones, polyurethanes, styrene-butadiene block polymers, and polyisobutylene (PIB) polymers and mixtures of the above.
It is known to provide non-crosslinked polyisobutylene (PIB) adhesives as a mixture of high molecular weight (HMW) and low molecular weight (LMW) PIBs with or without a plasticizer such as mineral oil or polybutene. In such formulations, the HMW PIB acts as an adhesive base, the LMW PIB acts as a tackifier, and a plasticizer, if present, acts to plasticize the adhesive to increase permeability of the adhesive to the drug and to modify the adhesive properties. Typical plasticizers include mineral oil, polybutene, and in some cases, such as with nicotine, the drug itself. A typical formulation of the prior art uses HMW PIB of 1.2M molecular weight LMW PIB of 35,000 molecular weight and plasticizer in a ratio of about 1:1.125:2.
It is also known to include additional tackifiers, if desired, to improve adhesive characteristics of such adhesives. PIB adhesives comprising a mixture of high, medium, and/or low molecular weight PIB's are disclosed in European Patent 0374980 and in U.S. Pat. Nos. 4,031,894, 4,559,222, 4,938,759, 5,312,627, and 5,508,038. PIB adhesive blends with butyl rubber or styrene radial or block type copolymers are disclosed in U.S. Pat. Nos. 4,551,490 and 5,059,189. The above patents are hereby incorporated in their entirety by reference.
DEFINITION OF TERMS
As used herein, the term “drug” is to be construed in its broadest sense to an any material which is intended to produce some biological, beneficial, therapeutic, or other intended effect, such as permeation enhancement, for example, on the organism to which it is applied.
As used herein, LMW PIB, refers to a PIB having a molecular weight within the range of 1,000-450,000 and HMW PIB refers to a PIB having a molecular weight within the range of 450,000-2,000,000.
As used herein, the term “predetermined administration period” refers to the period of time the transdermal delivery delay is designed to be maintained in contact with the skin of a patient to produce the desired therapeutic effect and is usually specified in the prescribing information supplied with the product.
As used herein, the term “transdermal” refers to the use of skin as a portal for the administration of drugs by topical application of the drug thereto.
SUMMARY OF THE INVENTION
According to this invention it has been discovered that transdermal drug delivery devices comprising adhesive formulations having certain adhesive properties can be successfully applied to, removed from and thereafter reapplied to non-scrotal skin without seriously degrading the adhesive properties after being removed.
Adhesive transdermal drug delivery devices may be removed and subsequently reapplied to an area of skin if the adhesive has an initial adhesive/skin bond strength sufficient to maintain said transdermal drug delivery device on the skin to which it is applied for the entire predetermined administration period; and an adhesive/skin bond strength upon replacement on the skin after removal therefrom prior to the end, if the predetermined administration period, which is adequate to retain the device on the skin for the balance of the administration period.
Accordingly, this invention relates to methods for the transdermal administration of a drug for a predetermined administration period wherein a transdermal delivery device is applied to non-scrotal skin, removed prior to the expiration of said administration period and thereafter reapplied for the balance of said administration period.
These and other aspects of the invention will become apparent to those of ordinary skill in the art in view of the detailed description that follows.
DETAILED DESCRIPTION OF THE INVENTION
I have found that certain transdermal adhesive formulations can be tailored such that they provide: (a) an adhesive/skin bond strength sufficient to maintain a transdermal drug delivery device on non-scrotal skin for the entire predetermined drug administration period; and (b) when removed from t
Alza Corporation
Date Vandana
Ghali Isis
Page Thurman K.
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