The present invention relates the iontophoretic delivery to a patient, in particular, to a patient having a thrombotic disorder, of a compound which blocks the binding of fibrinogen to the glycoprotein complex Gp llb/llla. The invention also relates to an iontophoretic delivery device suitable for such use.

Arterial thrombosis, in which platelet activation and aggregation are fundamental processes, makes a major contribution to cardiovascular mortality and morbidity, as evidenced by the incidence of myocardial infarction (1.5 million), unstable angina (1 million) and stroke (550,000) in 1992 in the USA alone. Newer therapies for these thrombotic conditions involve inhibiting platelet aggregation by administering a compound which is capable of blocking the binding of fibrinogen to its platelet receptor, Glycoprotein (Gp)llb/llla. With conventional delivery methods, a problem with this type of therapy which has been realised in the clinic, is that the dramatic anti-platelet effects of such compounds can increase the risk of haemorrhage in patients.

We have now proposed that this problem may be alleviated by administering Gpllb/llla antagonists by iontophoretic action. The principle of iontophoresis is that ionised (or polar) drug molecules can be driven across the skin and into the systemic system if an appropriate electrical potential is applied across the skin.

This mode of delivery allows such drugs to be administered at a constant and predictable rate so as to keep drug levels within the narrow therapeutic window. Use of iontophoretic delivery is particularly convenient for conditions where the drug is to be administered chronically over a period of several months as it allows for simple self-administration and encourages patient compliance.

Furthermore, an iontophoretic delivery system may be removed quickly and easily by the patient or clinician should the need to suddenly stop drug administration arise and normal platelet aggregation would quickly return.

According to the present invention, there is provided an iontophoretic drug delivery device characterised in that it comprises, as an active ingredient, an antagonist of Gp llb/llla. Suitably, said Gpllb/llla antagonist is ionised at pH 4 to

7. More suitably, the Gpllb/llla antagonist is highly potent, for example requiring a daily dose of less than 50mg/day, and is of low molecular weight.

Examples of Gpllb/llla antagonists which may be suitable in the invention include those described in: EP478363B; EP505868B; EP483667A; EP614360B; WO94/22820; Ohman, E.M. et al Eur. Heart J. (1195), 16 (Suppl. L), 50-55; Lincoff, A. et al, Am. J. Cardiol. (1997), 79(3), 286-291 ; and Timm, U. et al, J. Chromatogr., B: Biomed. Sci. Appl. (1997), 691(2), 397-407, all of which are incorporated herein by reference.

In a preferred aspect of the invention, the Gpllb/llla antagonist is of formula (I)

or a pharmaceutically acceptable derivative thereof, in which: X is either CH ₂ -CH ₂ or CH=CH; and

Y

I either A is ^{— N—} and B is -C=, or A is -CH= and B is -N- wherein Y is hydrogen or phenylmethyl wherein the phenyl group is optionally substituted by one or more halogen atoms (where halogen represents fluorine, chlorine, bromine or iodine).

In a further aspect of the invention, the iontophoretic delivery device comprises, as active ingredient, a compound selected from: {4-[6-(2-piperidin-4-yl-(E)-vinyl)-1 H-indazol-3-ylJ-piperidin-1 -yl}-acetic acid;

{4-[1 -(4-fluorobenzyl)-6-(2-piperidin-4-yl-(E)-vinyl)-1 H-indazole-3-yl]-piperidin-1 - yl}-acetic acid;

{4-[5-(2-piperidin-4-yl-(E)-vinyl)-indazol-1 -yl]-piperidin-1 -yl}-acetic acid;

{4-[5-(2-piperidin-4-yl-ethyl)-indazol-1 -ylj-piperidin-1 -yl}-acetic acid, and pharmaceutically acceptable derivatives thereof.

In a yet further aspect of the invention, the iontophoretic delivery device comprises, as active ingredient, a compound selected from: {4-[3-methanesulfonyl-5-(2-pιperidin-4-yl-ethyl)-indazol-1- yl]-piperidin-1-yl}- acetic acid;

{4-{3-carbamoyl-5-(2-piperidin-4-yl-ethyl)-indazol-1-yl]- piperidin-1-yl}-acetic acid;

{4-[1 -methanesulfonyl-6-(2-pιperidin-4-yl-ethyl)-1 H-indazol-3-yl}-pιperιdιn-1 -yl}- acetic acid; and pharmaceutically acceptable derivatives thereof.

By pharmaceutically acceptable derivative is meant any pharmaceutically acceptable salt, solvate or ester, or salt or solvate of such ester, of the compounds of formula (I), or any other compound which upon adminstration to the recipient is capable of providing (directly or indirectly) a compound of formula (I) or an active metabolite or residue thereof. In a preferred aspect, the Gpllb/llla antagonist is in the form of a hydrochloride salt.

In view of their fibrinogen antagonist activity, the iontophoretic drug delivery devices of the present invention are of interest for use in human and veterinary medicine, particularly in the treatment of thrombotic disorders. Particular examples of thrombotic disorders are known in the art and include occlusive vascular diseases such as myocardial infarction, cardiac fatalities, angina, transient ischaemic attacks and thrombotic stroke, arteriosclerosis, vessel wall disease, peripheral vascular disease, nephropathy, retinopathy, postoperative thrombosis, pulmonary embolism, deep vein thrombosis and retinal vein thrombosis. The iontophoretic drug delivery devices of the invention are also of interest for use in the prophylactic treatment of pen- and postoperative complications following organ transplantation (particularly cardiac and renal), coronary artery bypass, peripheral artery bypass, angioplasty, thrombolysis and endarterectomy

The iontophoretic drug delivery devices of the invention may also be useful for the treatment of other conditions in which the glycoprotein complex Gp llb/llla or other integrin receptors are implicated. Thus, for example, the iontophoretic

drug delivery devices of the invention may potentiate wound healing and be useful in the treatment of bone conditions caused or mediated by increased bone resorption. Particular examples of bone diseases are known in the art and include osteoporosis, hypercalcaemia of malignancy, osteopenia due to bone metastases, periodontal disease, hyperparathyroidism, periarticular erosions in rheumatoid arthritis, Paget's disease, immobilisation-induced osteopenia and glucocorticoid treatment.

The iontophoretic drug delivery devices of the invention may also be useful for the treatment of certain cancerous diseases, for example to prevent or delay metastasis in cancer.

According to a further aspect of the invention, there is provided an iontophoretic drug delivery device characterised in that it comprises, as an active ingredient, an antagonist of Gpllb/llla, for use in human or veterinary medicine, particularly for use in the treatment of a condition which is mediated through the Glycoprotein Gpllb/llla, for example a thrombotic disorder.

In the alternative, there is provided a method of treating a human or animal subject suffering from a condition which is mediated through the Glycoprotein complex Gpllb/llla, for example a thrombotic disorder, which comprises administering an effective amount of Gpllb/llla antagonist by iontophoretic action. Preferably, the method comprises administering the Gpllb/llla antagonist by an iontophoretic drug delivery device according to the invention.

The process of iontophoretic drug delivery is performed in general by putting the drug, or preferably an iontophoretic delivery device comprising the drug onto intact skin, for example on the arm, chest or the like. The iontophoretic delivery device may contain the drug in isolated form, but more preferably, the drug is in the form of a composition adapted for use in iontophoretic delivery. This composition may for instance be a solution (absorbed onto some porous material, such as a piece of filter paper or a piece of hydrophilic polyurethane) or a gel. The device is then covered by an electrode. A second electrode covering an inert reservoir composed of mainly ionic species is placed elsewhere on the skin, and a direct current source is connected between the electrodes in such a way that the electrode in contact with the drug assumes the

same charge as the ionised drug. Under influence of the electric field present, drug molecules migrate through the skin.

Therefore, according to a further aspect, the invention provides a pharmaceutical composition comprising an antagonist of Gp llb/llla, for example, a compound of formula (I) or a pharmaceutically acceptable derivative thereof, adapted for use in an iontophoretic delivery device.

A useful dose for a human patient, achievable by a device according to the present invention is up to 50 mg/day, preferably up to 25mg/day.

Appropriately, an iontophoretic device according to the present invention substantially as hereinbefore described may be in the form of a matrix of a solid, semi-solid or mucilaginous material having an active ingredient dispersed therein, and optionally having an active ingredient permeable membrane associated therewith. The matrix material is suitably a hydrogel, polyurethane, silicone or other material known in the art for holding a drug in a stable condition prior to release to the skin. Aptly, the matrix is in the form of a transdermal patch or pad, or the like, for transdermal administration of the active ingredient. Alternatively, a device according to the present invention may be in the form of a reservoir having therein a liquid medium containing therein an active ingredient, the reservoir having a membrane which is permeable for the active ingredient. The former option is preferred.

There is further provided by the present invention an iontophoretic drug delivery system which comprises:

(a) an iontophoretic drug delivery device substantially as hereinbefore described; and

(b) electrode means suitable for achieving current flow there between, whereby transdermal administration of an active ingredient to said human or animal subject can be effected.

The electrode means conveniently comprise an electrode system of an anode and a cathode which may be metal foils, polymer matrix loaded with metal powder, powdered graphite, carbon fibres or other suitable electrically conductive material. Suitable metals for use in electrodes are for instance platinum, silver, aluminium, copper, lead, iron, tin, chromium or zinc. Also metal/insoluble salt electrodes may be used, such as silver/silver halide electrodes, particularly silver/silver chloride electrodes. Platinum electrodes are used in some instances, however, silver/silver chloride electrodes are preferred.

The combined skin contacting areas of electrode assemblies can vary from less than 1 cm ² to greater than 200cm ² . The average device will have a contacting area from about 5cm ² to about 50cm ² .

A device according to the present invention can be suitably covered by a first electrode. Suitably, a second electrode can be placed elsewhere on the skin, and a direct current source can be connected between the electrodes in such a way that the first electrode in contact with the device containing the active ingredient assumes the same charge as the ionized active ingredient. Under influence of the electric field present, active ingredient molecules migrate through the skin. A current flows between the electrodes, part of which is carried by the active ingredient.

A delivery system according to the present invention may also preferably further comprise a power source, e.g. batteries and suitable control circuitry.

Iontophoretic devices and systems as such are known in the art, for instance from, WO-A 9116946, WO-A 9116944, WO-A 9116943, WO-A 9115261 ,W0-A 9115260, WO-A 9115259, WO-A 9115258, WO-A 9115257, WO-A 9115250, WO-A 9109645, WO-A 9108795, WO-A 9004433, WO-A 9004432, WO-A 9003825, EP-A 254965, US 4717378, EP-A 252732 and GB-A 2239803.

The present invention will now be illustrated by way of example:

Iontophoretic Transport of (4-f6-(2-piperidin-4-yl-(E)-vinyl)-1 H-indazol-3-yll- piperidin-1-yl>-acetic acid ( hereinafter referred to as Test Compound)

The Test Compound and other compounds of formula (I) as defined above may be prepared by methods described in copending applications PCT/EP95/05043 which has the publication number WO96/2012 and GB 9511989.7 which corresponds to PCT application number PCT/EP96/02536. The syntheses of further suitable compounds according to the invention have been described in GB 9613017.4, GB 9613095.0, and GB 9613018.2. The syntheses of all the compounds described above is obvious to a person skilled in the art of chemistry.

1. Method of Quantification

High performance liquid chromatography (HPLC) was used to determine the concentration of Test Compound in solution. The mobile phase consisted of 70:30 0.05% trifluoroacetic acid (TFA) in purified water: 0.05% TFA in acetonitrile. All solvents were HPLC grade. The λ _max was determined to be 237nm by scanning techniques and was used for the wavelength of detection in this assay. Flow rate was maintained at 1.δmUmin. A 15 x 0.46 cm Spherisorb phenyl column, 3μm packing was used.

2. Iontophoresis Method

Two sets of experiments were conducted using a Scepter iontophoretic system controller by Keltronic Corporation. The system consists of a PC, 6 sets of electrode leads, and 2 temperature leads. All currents used were DC. Current densities were held at 0.1mA/cm ² of skin or membrane (0.678cm ² ) equivalent to a current setting of 0.07mA. Currents were monitored over the time course of the experiment and were held within ±0.01 mA. Voltages and currents were checked independently using a hand-held voltmeter.

Electrodes were fabricated in the lab from silver wire (99.9985% pure, 0.5mm in diameter, Alfa Aesar Puratronic, Johnson Matthey). Preparation involved placing two equal lengths of silver wire in 0.5M KCI and applying a current of 1mA for 12 hours. This process is taken from the procedure demonstrated by Burnette and Ongpipattanakul, (1988), Journal of Pharmaceutical Sciences,

77(2), 132-7. The Ag:AgCI electrodes produced were coiled around a 22G 1.5inch syringe needle to produce a coil approximately 1.125inches in length and a lead of approximately 1.25inches. The total area of the electrode was 3.39cm ² . The anode (+) electrode (Ag) was placed in the donor solution in order to repel the positively charged drug substance across the membrane. The cathode (-) electrode (AgCI) was placed in the receptor side of the diffusion cell. The electrodes were located approximately 3cm apart.

Cell cultures utilized were produced from healthy human keratinocytes and were obtained from MatTek Corporation (EpiDerm EPI-606) and used upon receipt. Cultures were carefully removed from their support, rinsed with 0.1 M NaCI (receptor solution), and placed in the diffusion cells with the top exposed portion of the culture ("stratum corneum") facing the donor side of the cell set-up. Human cadaver skin was obtained from the International Institute for the Advancement of Medicine (HAM). Skin samples were cut into 2.5 x 2.5 cm squares and rinsed with water for injection containing 60μg/mL gentamicin before being placed in the diffusion cells (stratum corneum facing the donor compartment). Skin samples used in this study were from the thigh region and were dermatomed by HAM before shipment.

Six sets of Crown Glass side-by-side diffusion cells with magnetic stirrers were employed in each experiment. Four cells were run under iontophoretic conditions and two cells were run under passive conditions. A temperature of 32°C was maintained throughout the duration of the experiment by using a recirculating water bath. Temperature was monitored throughout the experiment by the Scepter system temperature probes. Experiments were conducted for 5 hours with the cell cultures and 8 hours with the skin samples. Additionally, 20 hours of passive data was collected for experiments using human cadaver skin. pH of the initial and final donor solution and sampled receptor solutions were measured using a Corning Ion Analyzer 255 pH meter and recorded All solutions were protected from light throughout the time course of the experiment

The donor solution consisted of an 8 5mg Test Compound/ml aqueous solution, pH 5, unadjusted The receptor solution consisted of 0 1M NaCI aqueous

solution adjusted to pH 5 with NaOH/HCI. The volume of the donor and receptor compartments were 3.5mL and the receptor compartment was emptied at each sample interval and filled with 3.5mL of fresh, pre-heated receptor solution. A mass balance was performed at the completion of each run.

3. Data Treatment

Standard area counts were entered into a spreadsheet and a linear regression analysis was performed on the average area counts versus concentration (μg Test Compound/mL). Content data for the samples were generated from area counts using the standard regression curve. The amount of Test Compound transported for each sample was calculated based on 3.5mL receptor solution volume. Cumulative amounts, instantaneous fluxes, and cumulative amounts per cm ² of skin or culture were subsequently determined from these values.

Steady state flux values were determined from cumulative μg Test Compound/cm ² versus time (hr) plots of the data. Regression analysis conducted on the steady state portion of these profiles provided flux data from the slope and lag time data from the x-intercept. The predicted anode area was determined by dividing the desired delivery rate (750μg Test Compound/hr) by the flux (μg Test Compound/cm ² hr). The predicted patch size was calculated by multiplying the anode area by 2.5 (anode + cathode + additional housing area) as recommended Sage Jr. & Riviere, (1992). "Model systems in iontophoresis-transport efficacy" Advanced Drug Delivery Reviews, 9, 265-287. Flux data was scaled linearly in order to predict the flux, anode area, and system size at other current densities.

Plasma levels were predicted based on the relationship:

where C _p is the predicted plasma level (ng/mL), J is the steady-state flux (μg/cm ² hr), A _an o _d e is the area of the anode (cm ² ), and Cl is the clearance (mL/min).

Human Keratinocvte Cell Cultures

The results obtained from this set of experiments are listed in Tables 1 and 2 as μg Test Compound/cm ² of culture available for transport. Active cells were run at a current density of 0.1mA/cm ² . System suitability standard checks were run five times throughout the analysis and results were found to be between 97.7 and 98.7% of the actual concentration based on regression analysis. A mass balance conducted at the conclusion of this experiment demonstrated at least 100% recovery from each diffusion cell set-up. All results are corrected for purity and reported in terms of the free base of the Test Compound.

Table 1 : Average Cumulative μq Test Compound/cm ² Transported - Active Transport Cultures -

Table 2: Average Cumulative UQ Test Compound/cm ² Transported - Passive Transport Cultures -

Human Cadaver Skin

The results obtained from this set of experiments are listed in Tables 3 and 4 as μg Test Compound/cm ² of skin available for transport. Active cells were run at a current density of 0.1mA/cm ² . System suitability standard checks were run seven times throughout the analysis and results were found to be between 93.5 and 94.6% of the actual concentration based on regression analysis. A mass balance conducted at the conclusion of this experiment demonstrated at least 100% recovery from each diffusion cell set-up. All results are corrected for purity and reported in terms of the free base of the Test Compound.

Table 3: Average Cumulative uo Test Compound/cm ² Transported

- Active Transport Skin -

Table 4: Average Cumulative ug Test Compound/cm ² Transported

- Passive Transport Skin -

Iontophoretic Feasibility Assessment

Based on the fluxes obtained and reported lag times, extrapolated fluxes at various current densities, and predicted patch surface area can be calculated These results are shown in Table 5 Also, by taking into account the estimated clearance value for this compound (250 mL/min), we can calculate the predicted plasma concentrations These predictions are also shown in Table 5

Table 5 Test Compound iontophoretic Transport Feasibility Results

^* calculated from cumulative amount/cm ² versus time plots, based on surface area of skin available for transport @ patch total area calculated is approximately 2 5χ(anode area) since cathode and system housing is required for complete device, based on steady-state flux values t Clearance = 250mL/mιn

The results obtained indicate that therapeutic plasma levels of Test Compound can be obtained by iontophoretic delivery of its hydrochloπde salt