Surgery – Diagnostic testing – Measuring or detecting nonradioactive constituent of body...
Reexamination Certificate
1998-03-10
2003-04-01
Lacyk, John P. (Department: 3763)
Surgery
Diagnostic testing
Measuring or detecting nonradioactive constituent of body...
C600S347000, C604S020000
Reexamination Certificate
active
06542765
ABSTRACT:
BACKGROUND OF INVENTION
1. Field of the Invention
The present invention relates to a device and to an in vitro method for modeling the iontophoretic sampling or delivery of substances through a membrane, such as the excised skin of a mammal. In another aspect, the present invention relates to a device and to a method for the iontophoretic delivery or sampling of substances through the intact skin of a living mammal. Specifically, the apparatus is a device which placed on the same side of intact skin has a positive electrode, a negative electrode and an electrically insulating material separating the electrodes. In still another aspect the present invention relates to an iontophoretic method of continuously monitoring the levels of bioactive materials in a subject and using a feedback mechanism to maintain effective levels.
2. Description of Related Art
Sampling-In-Vitro
C. C. Peck et al. in
Pharmacology Skin,
Vol. 1, pp. 201-208 published by Karger, Basel 1937, discloses a method to determine in vitro the outward transdermal migration of theophylline using a passive transdermal collection system (TCS). The use of electrical enhancement of the migration is not disclosed.
R. R. Burnette et al. in the
Journal of Pharmaceutical Sciences,
Vol. 75, No. 3, pp. 738-743, published in August 1986 using the standard diffusion cell discloses a comparison of the iontophoretic and passive in vitro transport of thyrotropin releasing hormone (TRH) across excised nude mouse skin. The results indicate that both charged and uncharged TRH fluxes across the excised tissue were greater than those obtained by passive diffusion alone.
In the standard (state of the art) arrangement for in vitro iontophoretic studies (See FIG.
6
), the two halves of a diffusion cell are placed horizontally side by side so that the skin is located vertically between them, with its epidermal side facing one half and its inner side facing the other. The bioactive preparation and the active electrode are put in the “epidermal” half of the cell, and the other side of the cell contains the passive electrode in a conductive fluid.
This side-by-side arrangement has several drawbacks and limitations. Since the passive electrode is, in effect, placed “inside” the skin, this configuration is not a good model of the in vivo case. The factors that influence such a non-physiological situation may not be those that are important in the clinical case. In addition, there are questions that cannot be investigated with a side-by-side configuration, such as the possibility of horizontal transport (i.e. within skin layers rather than vertically through the skin) and whether an iontophoretically driven drug is “pulled” back out of the skin by the passive electrode.
A state of the art iontophoretic drug delivery system, the Phoresor, is sold by Motion Control, Inc., 1290 West 2320 South, Suite A, Salt Lake City, Utah 84119.
Delivery-In-Vitro
In modeling studies, iontophoresis is useful to examine chemical transport of charged materials through a membrane, such as an excised skin sample. For instance, N. H. Bellantone, et al. in the
International Journal of Pharmaceutics,
Vol. 30, pp. 63-72, published in 1986, disclose a standard state-of-the-art side-by-side diffusion cell design and electrode configuration for various systems utilized for iontophoresis of benzoic acid (as a model compound) (see FIG.
6
). A number of limitations exist with the side-by-side cell design as is discussed further herein.
Delivery-In-Vivo
Iontophoresis is the electrically enhanced transport of charged substances usually bioactive materials. The procedure is a known means of transdermal drug delivery. For instance, in U.S. Pat. No. 4,141,359, by S. C. Jacobsen et al., which is incorporated herein by reference, disclose an improved iontophoresis device for the topical administration of ionic drugs or chemicals through epidermal tissue without mechanical penetration. The positive and negative electrodes are attached to the skin at separate locations. The ionic form of the drug is added to the appropriate electrode and is conducted into and through the epidermal tissue by means of direct current from a power source. A number of problems exist in this type of delivery, where the electrodes are separate.
Sampling-In-Vivo
There is a well-recognized and important need to sample and quantify bioactive substances in the body (typically, the blood). For example, it may be crucial to monitor the presence of a key endogenous biochemical for the purpose a disease diagnosis, or it may be essential to follow, and hence, optimize, the blood level of an administered drug during a chemotherapeutic regimen. Usually, the desired determination is achieved by analysit of a blood sample which is withdrawn invasively via an injected needle into a collection tube.
The passive transdermal collection of theobromine in vivo is also disclosed by C. C. Peck, et al. 1987, supra. No electrical current enhancement of the migration is disclosed.
No literature was found which describes a substantially noninvasive procedure for biomaterial sampling of the systemic circulation. It will require a unique application of iontophoresis to “extract” systemically circulating molecules into a collection device positioned on the skin or mucosal membrane surface. The present invention does not involve puncture of the skinner of any blood vessel.
Biosensing-In-Vivo
There exists a need to continuously or non-continuously monitor certain key biochemical parameters in hospitalized patients, and a need for a new class of medical devices to obtain real-time, on-line quantitation. A biosensor is a microelectronic device that utilizes a bioactive molecule as the sensing signal-transducing element.
K. W. Hunter, Jr., in
Archives of Pathological Laboratory Medicine,
Vol. III, pp. 633-636, published in July 1987, discloses in a general manner the range of devices and the physical properties which are examined. Hunter also includes a general diagram for a transdermal dosimeter. This reference does not provide needed additional specific information to create an operating biosensing-feedback-drug delivery system.
C. C. Peck et al. in the
Journal of Pharmacokinetics and Biopharmaceutics,
Vol. 9, No. 1, pp. 41-58, published in 1981, discusses the use of continuous transepidermal drug collection (CTDC) in assessing drug in-take and pharmacokinetics. It was concluded that. when back transfer is minimized, CTDC may be a useful tool to access the amount of drug exposure, etc., but offers little advantage over discrete sampling of other body fluids in the study of other aspects o rug disposition kinetics.
U.S. Patents of interest include: U.S. Pat. Nos. 4,329,999; 4,585,652; 4,708,716; 4,689,039; 4,702,732; 4,693,711; 4,717,378; 4,756,314; 4,699,146; 1,700,710; 4,706,680; 4,713,050; 4,721,111; 4 602,909; 4 595,011; 4,722,354; 4,722,726; 4,727,881; 4,731,049; 4,744,787; 4,747,819; 4,767,401.
Y. B. Bannon, European Patent Application Publication No. 252,732 (Jan. 13, 1988) to a transdermal drug delivery system is of general interest.
References of interest include:
W. Scharamm, et al., “The Commericalization of Biosensors,”
MD
&
GI,
pp. 52-57, publised in November, 1987.
A. F. Turners et al., “Diabetes Flellitus: Biosensors for Research and Management,”
Biosensors,
Vol. 1, pp. 85-115, published by Elsevier Applied Science Publishers, Ltd., England, 1985.
Y. Ikarlyaman, et al.,
Proc. Electrochem. Soc.,
1987, 87-9 (Proc. Symp. Chem. Sens.) 378. CA 107-(22); 207350n.
P. H. S. Tso, et al.
Anal Chem.,
1987, 59 (19), 2339, CA 107(14); 1262448.
H. Wollenberger, et al.,
K. Anal. Lett.,
1987, 20(5), 857, CA 107(9); 73551.
P. J. Conway, et al.,
D. A. Sens. Actuators,
1987, 11(4), 305, CA 107(5); 36151.
M. Mascini, et al.,
Clin. Chem.,
(Winston-Salem, N.C.) 1987, 33(4), 591 CA 107(5); 35851h.
I. Hanning, et al.,
Anal. Lett.,
1988 19(3-4) 461, CA 105(6); 48993q.
M. Shirchirl, et al.,
Diabetes Care,
1986, 9(3), 298. CA 105(5): 38426t.
S. J. Churchouse, et al.,
Anal. Proc.,
(London) 1986, 2395), 146 CA 105(3) 21117
Guy Richard
Rao Girish
Lacyk John P.
Peters Howard M.
Peters, Verny, Jones & Schmitt, L.L.P.
The Regent of the University of California
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