Formulations for the transdermal administration of fenoldopam

Details Formulations for the transdermal administration of fenoldopam Formulations for the transdermal administration of fenoldopam

1999-07-23

2004-03-02

Dodson, Shelley A. (Department: 1616)

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

06699497

ABSTRACT:

FIELD OF INVENTION
This invention relates to sustained release formulations for the safe and efficacious administration of fenoldopam for, among other things, the treatment of hypertension, congestive heart failure, and acute and chronic renal failure. More particularly, the invention relates to novel methods, compositions, and devices for transdermally administering fenoldopam to a subject through a body surface or membrane over a sustained time period.
BACKGROUND OF THE INVENTION
The transdermal route of parenteral delivery of drugs and other biologically active agents (“agents”) has been proposed for a wide variety of systemically acting and locally acting agents on either a rate-controlled or non-rate-controlled basis and is described in numerous technical publications such as the following: 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; 4,573,995; 4,588,580; 4,645,502; 4,698,062; 4,704,282; 4,725,272; 4,781,924; 4,788,062; 4,816,258; 4,849,226; 4,904,475; 4,908,027; 4,917,895; 4,938,759; 4,943,435; 5,004,610; 5,071,656; 5,122,382; 5,141,750; 5,284,660; 5,314,694; 5,342,623; and 5,635,203, the disclosures of which are incorporated in their entirety herein by reference.
When first investigated in depth in the late 1960's, the transdermal route of administration appeared to offer many advantages, particularly with respect to agents that had short half lives and therefore required frequent, repeated dosing or were subject to a high degree of first-pass metabolism by the liver. The peaks and valleys in blood concentration resulting from frequent periodic doses of short half-life agents would be eliminated and replaced by substantially constant plasma concentration. This would not only improve individual compliance but also would eliminate the alternating periods of high side-effects and ineffective blood concentrations associated with periodic dosing. Administering the agent through the skin directly into the blood stream would also eliminate first-pass metabolism of orally administered agents.
It was initially assumed, theoretically, that any short half-life agent of high potency and skin permeability would be suitable for safe and effective transdermal administration. This assumption, however, has not been proven true.
The failure of the transdermal route to fulfill the initial expectations of its potential as an administrative portal was primarily due to the incredible variety of properties with which nature has endowed the skin to permit it to perform its function as the primary barrier to prevent the ingress of foreign substances into the body. See Transdermal Drug Delivery: Problems and Possibilities, B. M. Knepp, et al, CRC Critical Reviews and Therapeutic Drug Carrier Systems, Vol. 4, Issue 1 (1987) and Transdermal Delivery Systems: A Medical Rationale, Gary W. Cleary, Topical Drug Bioavailability, Bioequivalence, and Penetration, Plenum Press, 1993. Thus, the transdermal route of administration, rather than being available to every short half-life agent of high potency and skin permeability, was found to be available only to those few agents that possess the proper combination of a host of characteristics, most of which are unpredictable, required to render the agent suitable for safe and effective transdermal administration.
The most significant of these characteristics are the following:
1. Skin Permeability. The permeability of the skin to the agent must be sufficiently high so that the agent can be administered at a therapeutically effective rate through an area of skin no greater than about 200 cm
2
and preferably no greater than 50 cm
2
. The person-to-person variation in skin permeability at similar sites should also be considered. U.S. Pat. Nos. 4,568,343, 4,746,515, 4,764,379, 4,863,738, 4,865,848, 4,888,354, 4,900,555, 5,378,730, 5,629,019, 5,641,504, 5,686,097, and WO 95/09006, WO 95/01167, WO 96/37231, and WO 96/40259 are related to various compositions and methods for enhancing permeation of drugs through the skin and are hereby incorporated in their entirety by reference.
2. Skin Binding. The skin beneath the transdermal delivery device has the capability of creating a skin depot of drug by absorbing, adsorbing, or binding a certain amount of agent. The amount of agent so bound must be supplied to the skin before the agent can be delivered into the blood stream at steady, therapeutically effective rates. If large amounts of the agent are bound in the skin, significant delays in the onset of therapeutic effect (“lag time”) will be observed together with corresponding delays in termination of effect upon removal of the device. The potential also exists for toxic quantities of potent agents to be contained within the skin beneath the device. Skin binding is not related to skin permeability. Agents that are highly permeable may also be highly bound causing a lag time sufficiently long as to render them unsuitable for their intended use.
3. Irritation. The skin reacts to many topically applied substances, particularly those maintained under occlusion, by blistering or reddening accompanied by unpleasant burning, itching, and stinging sensations. Animal models are used to screen for irritation. Animal models, however, often produce both false positives and false negatives. There is also a wide interpersonal variation in susceptibility to irritation. An agent must be minimally irritating in a large percentage of the target population in order to be suitable for safe and effective transdermal administration. U.S. Pat. Nos. 4,552,872, 4,756,710, 5,028,431, 5,130,139, 5,160,741, 5,304,379, and 5,451,407 are directed to overcoming problems of skin irritation associated with transdermal drug delivery and are hereby incorporated in their entirety by reference.
4. Sensitization. Sensitization is an allergic reaction which is induced when an agent is first applied to the skin and is elicited upon continued exposure which may occur immediately or after a long period of seemingly harmless exposure.
The sensitization may be local, elicited by topical exposure, which manifests itself as contact dermatitis accompanied by blistering, itching, reddening and burning at the site of application. More seriously, the sensitization may be systemic, elicited by topical application but manifesting itself by more general allergic reactions at sites other than the site of application. Most seriously, the systemic sensitization may be elicited by oral or intravenous administration of the drug. If the latter occurs, the individual will be unable to take the drug by any route of administration.
Animal models are used to screen for sensitization. Animal models, however, produce both false positives and false negatives. There is also a wide variation in the allergic reaction among individuals as well as between sexes, races and skin types. It is obvious that a useful transdermal agent must be minimally sensitizing in a large percentage of the target population. U.S. Pat. Nos. 5,000,956, 5,049,387, 5,120,145, and 5,149,539 are directed to overcoming sensitization problems associated with transdermal drug delivery by the coadministration of a corticosteroid and are hereby incorporated in their entirety by reference
5. Pharmacokinetic Properties. The half-life of an agent is the time after administration that half of the amount administered has been eliminated from the body. Because blood concentrations of continuously administered agents continue to increase for approximately five half-lives before steady-state constant blood concentrations are achieved, an agent must have a relatively short half-life to be suitable for continuous transdermal administration. The transdermal half-lives of most agents have not been determined. When half-lives of agents determined from intravenous administration are compared with half-lives determined from transdermal administration, the transdermal half-lives are generally longer but there can be wide variation in half-life between individuals based upon factors such

Affiliated with

Also associated with

Rating

Formulations for the transdermal administration of fenoldopam does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Formulations for the transdermal administration of fenoldopam, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Formulations for the transdermal administration of fenoldopam will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3214033