Comminuted form of 3- {4- [2- (4-tert-butoxycarbonylaminophenyl) ethoxy] phenyl}-(S)-2-<BR> ethoxy propanoic acid The present invention relates to a reduced particle size form of the compound 3- {4- [2- (4-tert-butoxycarbonylaminophenyl) ethoxy] phenyl}- (S)-2-ethoxy propanoic acid, as shown in formula I below, or a pharmaceutically acceptable salt thereof or a solvate or either thereof. The invention also concerns methods of treating one or more conditions associated with Insulin Resistance Syndrome using the reduced particle size form of the compound, or a pharmaceutically acceptable salt thereof in the manufacture of a medicament for use in one or more of said conditions. The invention further concerns pharmaceutical compositions containing the reduced particle size form of the compound, or a pharmaceutically acceptable salt thereof, or a solvate thereof, as an active ingredient, as well as processes for the manufacture of the reduced particle size form of the compound, or a pharmaceutically acceptable salt thereof.

In the formulation of drug compositions, it is important for the drug substance to be in a form in which it can be conveniently handled and processed. This is of importance from the point of view of manufacture of pharmaceutical formulations comprising the active compound.

The above compound is useful in treating metabolic disorders, such as, Insulin Resistance Syndrome (IRS), defined as reduced sensitivity to the actions of insulin in the whole body or individual tissues such as skeletal muscle, myocardium, fat and liver prevail in many individuals with or without diabetes mellitus. IRS refers to a cluster of manifestations including insulin resistance with accompanying hyperinsulinemia, possibly type II diabetes mellitus, arterial hypertension, central (visceral) obesity, dyslipidemia observed as deranged lipoprotein levels typically characterised by elevated VLDL (very low density lipoproteins) and reduced HDL (high density lipoproteins) concentrations and reduced fibrinolysis.

Recent epidemiological research has documented that individuals with insulin resistance run a greatly increased risk of cardiovascular morbidity and mortality, notably suffering from myocardial infarction and stroke. In type II diabetes mellitus these atherosclerosis related conditions cause up to 80% of all deaths.

In clinical medicine there awareness of the need to increase the insulin sensitivity in IRS and thus to correct the dyslipidemia which is considered to cause the accelerated progress of atherosclerosis. However this is not a universally defined disease.

We have discovered a reduced particle size form of the compound described above. This provides a basis for the present invention. Significant advantages can arise when the compound of formula I is in a reduced particle size form, for example, in the performance of the compound when it is manufactured so as to achieve uniform formulations with an even loading of active ingredient within as well as between batches. In addition reductions in particle size are typically associated with increased dissolution rates when administered orally and improved oral bioavailability, when oral bioavailability is limited by the dissolution rate of the active ingredient.

Accordingly provided in the present invention is a reduced particle size form of (S)-2-ethoxy-3- 4- [2- (4-tert-butoxycarbonylaminophenyl) ethoxy] phenyl}- (S)-2-ethoxy propanoic acid, as shown in formula I below or a pharmaceutically-acceptable salt or a solvate or either thereof.

By the use of the term"reduced particle size"we refer to solid Compound 1, or a pharmaceutically-acceptable salt thereof, or a solvate of either thereof, reduced by suitable processing techniques to a solid of smaller particle size and, consequently, greater surface area. Any number of processing techniques known in the pharmaceutical field may be used to reduce solid particle size, such as grinding, milling and micronising, reference should be made to Remington: The Science and Practise of Pharmacy, 19i Ed., pages 1598-1602, for a more exhaustive review.

By use of the term"solvated"we include hydrated.

Accordingly presented as a further feature of the invention is a process for the preparation of a reduced particle size form of the compound of formula I, or a pharmaceutically-acceptable salt or a solvate of either thereof, comprising comminuting a solid form of the compound of formula I, or a pharmaceutically-acceptable salt or a solvate of either thereof, for a sufficient period until the desired size of particle of the compound of formula I, or a pharmaceutically-acceptable salt or a solvate of either thereof, is generated.

The range of particle sizes preferred in this invention start from, in increasing preference, moderately fine powder, fine powder, very fine powder, microfine powder to, most preferably, superfine powder.

The above references to particle sizes are taken from the British Pharmacopoeia 1993, Volume II, Appendix XVII B, A193, and are reproduced below for reference.

Moderately fine powder A powder all the particles of which pass through a sieve with a nominal mesh aperture of 355pm and not more than 40.0% by weight pass through a sieve with a nominal mesh aperture of 250pm.

Fine powder A powder all the particles of which pass through a sieve with a nominal mesh aperture of 180pm and not more than 40.0% by weight pass through a sieve with a nominal mesh aperture of 125pm.

Veryfine powder A powder all the particles of which pass through a sieve with a nominal mesh aperture of 125pm and not more than 40.0% by weight pass through a sieve with a nominal mesh aperture of 4511m.

Microfine powder A powder of which not less than 90% by weight of the particles pass through a sieve with a nominal mesh aperture of 45pm.

Superfine powder A powder of which not less than 90% by weight of the particles pass through a sieve with a nominal mesh aperture of I Optm.

The particular sieves to be used in determining the particle size are described in British Pharmacopoeia 1993 Volume II, Appendix XVIIB, A193-A194, which part is incorporated herein by reference.

A feature of the invention is a reduced particle size form of a compound of formula I, as described above, for use in medical therapy.

According to a further feature of the invention there is provided a pharmaceutical composition which comprises a reduced particle size form of a compound of formula I, as described above, in association with a pharmaceutically-acceptable diluent, adjuvant or carrier.

The composition may be in a form suitable for oral use, for example a tablet, capsule, aqueous or oily solution, suspension or emulsion; for topical use, for example a cream, ointment, gel or aqueous or oily solution or suspension; for nasal use, for example a snuff, nasal spray or nasal drops; for vaginal or rectal use, for example a suppository; for administration by inhalation, for example as a finely divided powder such as a dry powder or a liquid aerosol; for sub-lingual or buccal use, for example a tablet or capsule; or for parenteral use (including intravenous, subcutaneous, intramuscular, intravascular or infusion), for example a sterile aqueous or oily solution or suspension. In general the above compositions may be prepared in a conventional manner using conventional excipients.

The amount of the reduced particle size form of a compound of formula I, as described, above that is combined with one or more excipients to produce a single dosage form will necessarily vary depending upon the host treated and the particular route of administration. For example, a formulation intended for oral administration to humans will generally contain, for example, from 0.01 mg to 50mg of active agent compounded with an appropriate and convenient amount of excipient (s) which may vary from about 20 to about

99.99 percent by weight of the total composition. Dosage unit forms will generally contain about 0.0001 mg to about 1 mg of an active ingredient.

The invention also includes the use of a Compound of the invention, as described above in the production of a medicament for use in:- (i) treating dyslipidaemia; (ii) treating type II diabetes mellitus; (iii) treating hyperlipidaemia (iv) treating hyperglycaemia; (v) treating hyperinsulinaemia ; (vi) treating arterial hypertension; and/or (vii) treating abdominal obesity.

The invention also includes a method of producing an effect as defined hereinbefore or treating a disease or disorder as defined hereinbefore which comprises administering to a warm-blooded animal requiring such treatment an effective amount of a reduced particle size form of a Compound of formula I, as described above.

The size of the dose for therapeutic or prophylactic purposes of a reduced particle size form of a Compound of the invention, as described above, will naturally vary according to the nature and severity of the medical condition, the age and sex of the animal or patient being treated and the route of administration, according to well known principles of medicine.

Suitable daily doses of the compounds of the invention in therapeutical treatment of humans are about 0.001-10 mg/kg body weight, preferably 0.01-1 mg/kg body weight.

The comminuted form of the compound of formula I may be administered as a sole therapy or they may be administered in conjunction with other pharmacologically active agents such as a anti-diabetic, anti-hypertensive, diuretic or anti-hyperlipidemic agent.

The invention will now be illustrated in the following non-limiting Examples.

Example 1 Svnthesis of 3- (2-f4-tert-Butoxvcarbonylaminophenyl) ethoxv phenyll- (S-2-ethoxy propanoic acid Ethvl 3- [4-[2-l4-tert-butoxvcarbonylaminophenvlethoxYphenyl]- (Sy-2-ethoxv propanoate Ethyl (S)-2-ethoxy-3- (4-hydroxyphenyl)-propanoate (250g, 1.05 mol, 1.0 eq) was dissolved in dimethylsulpoxide (DMSO) (1000 ml). When a homogenous solution was formed, NaOH (s), beads, 20-40 mesh (48.2 g, 1.21 mol, 1.15 eq) was added. 1- (4- Methyl) phenylsulfonyloxy-2- [ (4-tert-butoxycarbonylamino) phenyl] ethane (431 g, 1.10 mol, 1.05 eq) was dissolved in DMSO (1000 ml). The DMSO solution of 1- (4-methyl) phenyl- sulphonyloxy)-2- [4- (tert-butoxycarbonylamino) phenyl] ethane was then added over 10 minutes at 20-25 °C to the solution of ethyl (S)-2-ethoxy-3- (4-hydroxyphenyl)-propanoate.

The reaction mixture was then stirred for 1 hour. To fully convert ethyl (S)-2-ethoxy-3- (4- hydroxyphenyl)-propanoate to ethyl 3- [4- [2- (4-tert- butoxycarbonylaminophenyl) ethoxy] phenyl]- (S)-2-ethoxy propanoate an additional amount of 1- (4-methyl) phenylsulfonyloxy-2- [ (4-tert-butoxycarbonylamino) phenyl] ethane (20 g, 0.05 mol, 0,05 eq) and NaOH (s), beads, 20-40 mesh (2.1 g, 0,05 mol, 0.05 eq) was added. The reaction mixture was stirred for another 3 hours. The mantle was then cooled to 10°C.

3- [4-12- (4-tert-Butoxycarbonylaminophenyl) ethoxylphenyll- (S)-2-ethoxy propanoic acid NaOH (aq) 1M (1.15 1, 1.15 mol, 1.15 eq) was added to a solution of ethyl 3- [4- [2- (4- tert-butoxycarbonylaminophenyl) ethoxy] phenyl]-(S)-2-ethoxy propanoate over 30 minutes at 19-23 °C. Stirring was continued for 1 hour, and then H, O (4000 ml) was then added. The water layer was washed with methyl tert-butylether (3x2000 ml). The water layer was then acidified to pH 3 with KHSO4 (aq) 1M (1.6 L, 1.6 mol, 1.6 eq). The acidic water solution was then extracted with ethylacetate (3x2000 ml). The ethylacetate-parts were put together and washed with H2O (4x2000 ml). The ethylacetate solution was dried with MgS04 (90 g). The salts were filtered off and washed with ethylacetate (3x100 ml). The filtrate was evaporated to dryness. The oil residue (750 g) was dissolved in toluene (1750 ml). The solution was seeded with 3- [4- [2- (4-tert-butoxycarbonylaminophenyl) ethoxy] phenyl]- (S)-2-ethoxy propanoic acid and the crystallisation was continued for 30 minutes. Then isooctane (3500 ml) was added.

The slurry was stirred for 15 minutes and then filtered. The solid was washed with

toluene : isooctane 1 : 2 (400 ml) followed by water (300 ml). Drying at 40°C at reduced pressure yielded 382 g (0.89 mol) of 3- [4- [2- (4-tert-butoxycarbonylaminophenyl) ethoxy] phenyl]- (S)-2-ethoxy propanoic acid as a white powder.

Example 2 Preparation of Reduced Particle Size Form of Example 1 bv Micronisation Screw feeder: KTron T20 Jet mill : Titannitride coated steel inside equipment with classifier.

Mill ring: Area of jet hole 1.8 mm2 (100% ring) Humidity: The relative humidity should not exceed 35% The micronised compound is collected in a 25L-aluminium can, first cleaned with ethanol and dried.

The mill is connected to nitrogen gas. The filter stocking is connected to the nitrogen gas discharge. The aluminium can is connected to the other end of the filter stocking to collect the fine fraction of compound.

The compound is charged to the screw feeder so that the lower part of the screw feeder is filled.

Volumetric screw, eeder : The charging rate should be set at 675 g/min (4 kg/h) using a balance and a timer.

The amount of discharged compound should be controlled over at least one minute. The discharged compound is collected in a stainless steel vessel and recharged to the screw feeder.

Gravimetric screw feeder : Set the charging rate to 675 g/min (4 kg/h). Discharge the compound until the right flow has been achieved. The discharged substance is collected in a stainless steel vessel and recharged to the screw feeder.

A tarred aluminium can is placed under or beside the cyclone. A stainless steel vessel is placed under the cyclone. A plastic bag is connected at the cyclone to guide the compound down to the vessel and into the aluminium can.

The milling pressure at the pipe is set so that a pressure of 5. 70. 3 bar is achieved in the outer chamber.

The ejector pressure is set so that the same pressure is achieved for the ejector pipe pressure as for the milling pipe pressure.

The compound collected during the first 20 seconds of micronisation is collected in the stainless steel vessel. After the first 20 seconds the compound is collected in the aluminium can. All the material that leaves the mill when the screw feeder is turned off should be collected in the stainless steel vessel. Both the material collected at the start and the finish of the micronisation should be discarded.