WO2005044280A1

WO2005044280A1 - Biphosphonate pharmaceutical formulations (water emulsion of lipids/phospholipids) and use thereof

Info

Publication number: WO2005044280A1
Application number: PCT/EP2004/012660
Authority: WO
Inventors: CONSULTING S.r.l. BIXIO
Original assignee: Individual
Current assignee: Individual
Priority date: 2003-11-11
Filing date: 2004-11-09
Publication date: 2005-05-19
Anticipated expiration: 2006-05-11
Also published as: ITMI20032175A1

Abstract

The present invention refers to bisphosphonate pharmaceutical formulations and the use thereof for the preparation of an injectable medicament for the treatment of pathologies sensitive to the action of BPs among which there are some pathologies of the skeletal system. Such formulations comprise a solubilizing/dispersing vehicle comprising a water emulsion of lipids for instance mono-, di-or triglycerides; soy bean, olive or fish oils and/or phospholipids for instance phosphatidylcholine; soy bean lecithin or egg yolk lecithin and show high tolerability.

Description

BIPHOSPHONATE PHARMACEUTICAL FORMULATIONS (WATER EMULSION OF LIPIDS/ PHOSPHOLIPIDS) AND USE THEREOF

The present invention refers to bisphosphonate (BP) pharmaceutical formulations and the use thereof. In particular, the present invention concerns pharmaceutical formulations comprising substances belonging to the class of bisphosphonates (BPs) and to the use thereof for the preparation of an injectable medicament for the treatment of pathologies sensitive to the action of BPs among which there are some pathologies of the skeletal system. BPs are well known drugs and are widely used in the clinical practice against all those pathologies of the skeletal system provoking an excessive bone loss. The affinity of BPs to bone tissue results to be the basis for their use as inhibitors of ectopic calcification and of bone resorption. From the physicochemical point of view, their strong binding to calcium phosphate crystals inhibits their growth, aggregation and dissolution, and their direct interaction with osteoclasts and/or osteoblasts limits at the end the bone resorption and turnover.

Known indications to treatment with BPs are Paget's disease, bone metastases, ectopic ossification, hypercalcemia of cancer origin, osteoporosis, hyperthyroidism. Many BPs have been already approved for human therapy, others are in an advanced phase of clinical experimentation.

In the clinical practice, the administration route of BPs by far preferred, as it happens with all chronic therapies, should be the oral route, which is also the most pleasant one to the patient: however, in the case of BPs, this simple Λvay of administration presents the serious inconvenience of a very low oral bioavailability, the absorption from the gastroenteric tract being, f.i., equal to about 0.75% for alendronate (B. Gertz et al., Osteoporos. Int. 53, 513-516,1993), about 0.3% for pamidronate (P. T. Daley Yates et al., Calcif. Tissue Int. 49, 433-435, 1991), 1-2% for clodronate (G. L. Plasker et al., Drugs, 47, 945-982, 1994), and hardly reaching 3-7% for etidronate (R. R. Recker et al., Toxicol. Appl. Pharmacol., 24, 580-589, 1973). Values of oral absorption of the same order are also obtained in the various animal species as rats and dogs (L. Hyldstrup et al, Calcif. Tissue Int., 53, 297-300. 1993; G.J.Yakatan et al, Clin. Pharmacol. Ther., 31, 402-410, 1982), so confirming this to be a general problem with the BP family: such negative property is probably due - in spite of the very high solubility of BPs and their alkaline salts - to the very strong polarity deriving from their molecular structure. To get through this difficulty, much larger doses of BPs are usually administered, but this means on one side that the highest quantity of the drug administered, as f.i. 98-99%, is not absorbed and is then lost to therapeutic effect, and on the other side that much stronger side effects are obtained, particularly at gastrointestinal level, as diarrhoea, nausea and vomiting (D.J. Dodwell et al., Br. J. Cancer, 61, 123-125, 1990; H. I. Harinek et al., Brit. Med. J. Clin. Res. Ed., 295, 1301-1305, 1987), as well as gastric irritation and ulcer (A. Fitton et al., Drugs, 41, 289-318, 1991). The most severe side effect deriving from the ingestion of high doses of BPs involves however the upper gastrointesinal tract, particularly the esophagus, and appears then in the form of a severe simptomatology typical of erosive oesophagitis, gastroesophageal reflux, etc. (P. C. de Groen et al., New Engl. J. Med., 335, 1016-1021, 1996), leading to discontinuation of therapy. The use precautions result to be generally only ineffective palliatives (immediate swallowing; ingestion in fasting conditions and drinking much water; standing for at least 30 minutes after ingestion; and so on). The intravenous route of administration, while being scarcely applicable to home patients as it is the case with most osteoporotic patients, and in the more frequent case of the chronic therapeutic use, is however quite acceptable on the therapeutic point of view and in hospital premises, taking caution not to carry out a too rapid injection which would bring about a reduced binding with the bone tissue and an increased and fast urinary excretion. It presents however the risk to provoke some damage to the site of injection, as vasal endothelium inflammation, flebitis and even local necrosis, particularly dangerous in the case of occasional extravasation. Because of the irritating effect of BP solutions, the intravenous route presents the further problems of requiring a high dilution in saline solution, f.i. 100-500 ml; a slow infusion, f.i. 2-3 hours, and so on. The administration by the intramuscular route could be by far preferred, since it has been demonstrated it does not present any bioavailability problem and is easily adopted even for in house patients; however, it shows severe problems too, because intramuscular injection of BPs provokes strong irritation at the injection site, with serious damages to muscular tissue and local pain often defined by the patient as unbearable. As a matter of fact, only bisodium clodronate - and only in few countries - is occasionally administered by i.m. route; in such patients anyway, the local effect provoked by a weekly injection (the daily use is excluded a priori) attenuates very slowly and the entire gluteal area may remain unavailable to further injections for a few months (M. Rossini et al, Bone, 24, 125-129, 1999). EP 1,136,069 discloses some tolerance improvement, in terms of a decrease of induced pain, by increasing the pH of solution from 4.2 -which is proper to bisodium clodronate - to the range from pH 4.5 to the roughly neutral pH.

We have now surprisingly found that such side effects, f.i. after i.m. administration (as strong pain, tissue damage and necrosis, etc.) but even following i.v. infusion (inflammation, onset of phlebitic forms, etc.) of substances belonging to the BP class, may be strongly limited or even avoided by using an injectable pharmaceutical formulations wherein the BP compound is solubilized/dispersed in a lipid and/or phospholipid pharmaceutically acceptable water emulsion. By the way, it is emphasized that it is quite unusual and surprising the use of lipid and/or phospholipid emulsions as vehicles of drugs as BPs which are, both in the form of acids and of salts, strongly soluble in water and then, as a general rule, should be solubilized and used in an aqueous medium, typically in sterile distilled water, saline (0.9% sodium chloride solution) or glucose solution (5% glucose). Among the aspects of the present invention is therefore a pharmaceutical formulation comprising a compound of the bisphosphonate class in a solubilizing/dispersing vehicle comprising a pharmaceutically acceptable water emulsion of lipids and/or phospholipids. In particular, the compound of the BP class is selected from the group consisting of a bisphosphonic acid and/or a pharmaceutically and pharmacologically acceptable salt with a monovalent cation or an in vitro or in vivo precursor thereof; the compound of the BP class can be under an anhydrous or hydrate -crystalline, amorphous or polymorphous- form, as a racemate, enantiomer or diastereoisomer.

Preferably, the compound of the BP class comprised in the formulation of the invention has the following general formula (I): (OH)₂OP-CR₁R₂-PO(OH)₂ (I) wherein Ri and R₂, which can be equal or different between them, represent hydrogen; halogen; hydroxyl; substituted or unsubstituted amino, thio, C₁-C₃ alkyl or Cι-C₆ aminoalkyl groups; or a pharmaceutically acceptable salt or in vitro or in vivo precursor thereof. More preferably, R] and/or R₂ in the above formula (I) represent chlorine; an amino group enclosed in a heterocycle; a C₁-C₃ alkyl substituted with an isolated or condensed homo- or hetero- cycle, the latter cycle containing 1 or 2 hetero-atoms; in particular, the hetero- atoms in the heterocycles are nitrogen atoms.

Also preferred is that the BP compound comprised in the formulation of the invention is a bisodium salt; in particular, the BP compound is selected from the group consisting of bisodium etidronate, clodronate, risedronate, zoledronate, pamidronate, alendronate, neridronate, ibandronate, olpadronate, icadronate, tiludronate.

Mostly preferred are the formulations of the invention wherein the BP compound is clodronic acid or bisodium clodronate.

According to a preferred embodiment, the BP compound comprised in the formulation of the invention is in an amount of 0.1-500 mg, preferably 1 -300 mg.

The volume of the formulation can widely range depending on the administration route as it will be apparent to the average man skilled in the art; preferably it ranges from 0.5 to 500 ml, more preferably from 5 to 10 ml (f.i. in the case of bolus intravenous administration) and most preferably from 1 to 5 ml (f.i. in the case of intramuscular use). 100 to 500 ml can be administered in the case of slow (1 hour or more) intravenous infusion.

According to another preferred embodiment, the solubilizing/dispersing vehicle of the formulation of the present invention is an oil in water emulsion; in particular, the emulsion comprises lipids and/or phospholipids of different origin such as animal, vegetable, synthetic or semi-synthetic (f.i. hydrogenated or re-synthesized fats) origin, or a mixture thereof.

Lipids can be selected from the group consisting of mono-, di-, or tri-glycerides, or a mixture thereof, tryglicerides being preferred; in particular, they can be selected from the group consisting of soy bean, olive or (either purified and/or concentrated) fish oils, or a mixture thereof, although any other lipid species suitable for pharmaceutical use can be used, as it will result evidently to the average man skilled in the art. Preferably, lipids, in the formulation of the present invention are in an amount from 1 to 25%, in particular from 10 to 20 %. Phospholipids can be selected from the group consisting of soy bean lecithin or egg yolk lecithin (egg yolk phospholipids), or a mixture thereof; in particular, they can be selected from the group consisting of distearoilphosphatidylcholine, dimyristoilphosphatidylcholine, dimyristoilphosphatidylglycerol, phosphatidylethanolamine, phosphatidylserine, phosphatidylinositol, phosphatidylcholine, or a mixture thereof. Phosphatidylcholines are more preferred. Preferably, phospholipids, in the formulation of the present invention are in an amount from 0.05 to 10%, in particular from 0.1 to 5%.

The lipids and/or phospholipids comprised in the formulation of the invention are advantageously hydrogenated. The formulation of the invention can also preferably comprise a pharmaceutically acceptable excipient and/or adjuvant , such as those currently used in the field which are commonly selected by the average man skilled in the art for injectable preparations; such excipient and/or adjuvant can be conveniently selected from the group consisting of sugars (such as, f.i., lactose, glucose, saccharose, or maltose), polyalcohols (such as, f.i., glycerol, mannitol or xilitol), dispersing/suspending agents (such as, f.i., povidone), preservatives (such as, f.i., benzyl alcohol or a paraben), ionic or non-ionic surfactants (such as, f.i., sodium laurylsulfate, sodium deoxycholate, a polysorbate, Cremophor), basic or neutral or acid buffers (such as, f.i., alkaline carbonates or bicarbonates, phosphates, or TRIS buffer) and other additives, such as co-solvents, stabilizers and antioxidants and the like. As above noted, the BPs salts comprised in the formulation of the present invention are preferably the sodium salts having different degree of salification (mono-, bi-, tri-sodium, etc.); even the salts of potassium and other inorganic and organic cations, acceptable on the pharmaceutical and pharmaco-clinical point of view (ammonium and variously substituted ammonium salts, lysine and arginine salts, choline and ethanolamine, glutamine and glucosamine salts, etc.), also having different degree of salification. Preferably, the formulation of the invention comprises lipids and/or phospholipids in the form of droplets, vesicles, nanospheres, having a particle size lower than about 5 microns, preferably lower than about 3 microns and most preferably lower than 1 micron. The formulation of the invention comprises a pharmaceutically effective amount of the compound of the bisphosphonate class per dose unit, depending on the potency of the compound, as the average man skilled in the art will easily understand.

With reference to the dose of the actual oral formulation, the dose of the formulation of the invention, will be from equal to about one hundred times lower, in consideration of the mean bioavailability increase of the injectable administration in comparison with the oral one, of the intervals among the administrations and other factors. According to another aspect, the invention also concerns the use of the formulation as above defined for the preparation of an injectable medicament for the treatment of pathologies sensitive to the action of the compounds of the BP class. A still further aspect of the invention concerns a method for the treatment of pathologies sensitive to the action of the compounds of the BP class in a mammal in need thereof comprising administering to the mammal a therapeutically effective dose of the formulation of the invention which ranges from about 0.002 to 10 mg/kg of body weight per day, referring to a body weight of 50 kg.

Preferably, the mammal is administered the formulation of the invention either daily or intermittently, or each other day, each 7, 10, 14 days, each month, until discontinuous use each 6-12 months . In particular, the mammal is administered a dose of the formulation of the invention either intravenously or intramuscularly, most preferably intramuscularly. In the intermittent use, the dose unit will be increased, with the maximum criterion of proportionality, as it will be easily understood by the average man skilled in the art. As a whole, the BPs dose unit will range from 0.1 to 500 mg, more frequently from 1 mg to 300 mg.

Because of their high hydrosolubility and polarity, it is believed that BPs result to be dispersed in the watery phase of the emulsion and are not included in the lipidphospholipid phase. It is also believed that the presence of such a peculiar vehicle makes the formulation of the invention particularly well tolerated by the surrounding tissue, the administration thereof therefore resulting free from painful local effects.

The formulation of the invention can be prepared in different ways, as the average man skilled in the art will easily understand. For instance, the formulation of the invention can be prepared so that it comprises the BP compound already included in the lipid and/or phospholipid emulsion together with any eventual excipient and/or adjuvant; alternatively, the formulation of the invention may comprise the BP compound in an anhydrous state (in the form, for instance, of a lyophile) or in an aqueous solution, together with any possible excipients and/or adjuvants, separated from the lipid and/or phospholipid emulsion and any possible excipients and/or adjuvants (for instance, placed in a vial or a pre-filled syringe); the BP compound and the emulsion are then extemporarily mixed before the therapeutic administration, for all indications already forecasted for the presently known oral and parenteral BP formulations.

All the above mentioned products (lipids, phospholipids, excipients, etc.) are commercially available and must possess characteristics (such as purity and the like) suitable for the parenteral use. In the case of extemporarily dissolving/dispersing the BP compound in a preformed emulsion, an emulsion suitable for the total parenteral nutrition (TPN) can be selected among the commercially available ones.

In any case, particular care must be addressed to the stability of the emulsion to avoid the separation of any lipid phase (resulting in the so called "creaming effect"), potentially due to the addition of BP, excipients and salt ions soon after the preparation of the final formulation, or during the shelf life of the product. This problem is anyway easily solved by the average expert in the field, who will arrange -depending on the selected BP compound- to suitably modify the emulsion concentration, pH, salt concentration and any possible further parameter as usual in the art, so to get through the inconvenient. Further and evidently, the formulation of the invention has to be isotonic and sterile as it will be easily understood by the average man skilled in the art.

For the industrial preparation of the BP emulsion, the use of peculiar equipment may be required such as, for example, colloidal mill, pressure homogenizer, ultrasound generator, and the like, also in order to guarantee the required particles distribution interval and homogeneity, as it will result evident to an average expert in the field.

As already mentioned, the formulation of the invention, including BPs in a lipid and/or phospholipid emulsion, is surprisingly able to reduce or even to avoid the local irritating effects frequently arising with the usual aqueous solutions thereof, both when they are used by intravascular route, and above all when used by intramuscular route. In particular, inflammation, tissue damage, local necrosis, and subsequent pain result to be thus avoided. It is thought that a lipid layer or barrier would avoid or limit the direct contact of the drug with the mucosal surfaces, venous endothelium and muscular fibre cells, preventing any local damage and pain. The following examples illustrate the invention without limiting it. Example 1 Composition

Vial A (Active ingredient): Bisodium clodronate 100 mg

Vial B (Diluent): Soybean lipids 330 mg egg yolk phospholipids 39.60 mg glycerol 74.25 mg (sterile, non pyrogenic) water for injection q. s. to 3.3 ml

Preparation: the diluting emulsion was prepared according to standard methods, as known to the expert. The bisodium clodronate vial (neutral glass, low calcium content) was obtained by dosing sterile powders or by lyophilization of aqueous solutions. The final formulation was obtained by adding vial A to B before use, shaking shortly and administering preferably by intramuscular route. Example 2 Composition Vial A (Active ingredient): Bisodium clodronate 100 mg water for injection, q. s. to 1.65 ml

Vial B (Diluent): Soybean lipids 330 mg egg yolk phospholipids 39.60 mg glycerol 74.25 mg water for injection, q. s. to 1.65 ml Preparation: it is carried out as in Example 1, but an aqueous solution of bisodium clodronate, filtered through a 0.22 micron membrane under sterile conditions, is used in vial A.

Example 3

Composition: as in final solutions described in Examples 1 and 2.

Preparation: the final composition is obtained and stored in one vial ready to use.

Example 4

Composition A vial contains: Bisodium clodronate 100 mg soybean lipids 330 mg egg yolk phospholipids 39.60 mg glycerol 74.25 mg benzyl alcohol 35 mg sodium bicarbonate, q. s. to pH 5 water for injection, q. s. to 3.30 ml Preparation: the diluting solution, constituted by lipids, phospholipids and glycerol in water, is added with benzyl alcohol and, after inclusion of clodronate, the pH of the final composition is adjusted with the buffer. Example 5

Composition: as in Example 1-4, but the active ingredient is represented by bisodium clodronate tetrahydrate or by clodronic acid.

Preparation: according to Examples 1-4. If clodronic acid is used, the final formulation is preferably buffered as in Example 4. Example 6

Composition

A vial contains: Bisodium clodronate 100 mg soy bean lipids 200 mg egg yolk phospholipids 24 mg glycerol 45 mg benzyl alcohol 35 mg sodium bicarbonate, q. s . to pH 7 water for injection, q. s. ' to 2 ml

Preparation: the procedure of Example 4 is followed, obtaining a final composition to be preferably administered by intramuscular route.

Example 7 Composition

A vial contains: Bisodium clodronate 300 mg soy bean lipids 1000 mg egg yolk phospholipids 120 mg glycerol 225 mg sodium bicarbonate, q. s. to pH 5.5 water for injection, q. s. to 10 ml Preparation: the procedure of Example 4 is followed, obtaining a final composition to be preferably administered by intravenous route. The solution can be further diluted to 100 ml or more, for slow intravenous infusion in 1-3 hours. Example 8 Composition Vial A (Active ingredient): Bisodium clodronate 200 mg povidone 200 mg sodium hydroxide, q. s. to pH 5.5 water for injection, q. s. to 4 ml Vial B (diluent): Soy bean lipids 400 mg egg yolk phospholipids 48 mg glycerol 90 mg benzyl alcohol 100 mg water for injection, q. s. to 4 ml Preparation: the solution of vial A is submitted to lyophilization and the product is added with the emulsion of vial B, shaken shortly and administered by parenteral route. Example 9 Composition

A vial contains: Bisodium clodronate 100 mg soy bean lipids (soy bean oil) 330 mg soy bean phospholipids (soy bean lecithin) 39.6 mg glycerol 74.25 ^: mg water for injection, q. s. to 3.3 ml Preparation: the emulsion of soy bean lipids, soy bean lecithin and glycerol in water, was added with bisodium clodronate. The content of a vial is shaken shortly, brought to the requested volume and injected by intramuscular route. Example 10 Composition

A vial contains: Bisodium clodronate 100 mg triolein 330 mg egg yolk phospholipids 39.6 mg glycerol 75 mg water for injection, q. s. to 3.3 ml

Preparation: as described in Example 9.

Example 11

Composition

A vial contains: Bisodium clodronate 100 mg distearoylphosphatidylcholine 60 mg glycerol 75 mg sodium bicarbonate, q. s. to pH 5.5 water for injection, q. s. to 3.3 ml

Preparation: the emulsion of distearoylphosphatidylcholine and glycerol in water, Λvas added with bisodium clodronate and treated according to Example 9. Example 12

Composition A vial contains Bisodium pamidronate 60 mg soy bean lipids 1000 mg egg yolk phospholipids 120 mg glycerol 225 mg water for injection, q. s. to 10 ml Preparation: as described in Example 9, to be preferably used by intravenous route. Example 13 Composition A vial contains : Bisodium pamidronate 15 mg soy bean lipids 300 mg egg yolk phospholipids 36 mg glycerol 67.5 mg benzyl alcohol 35 mg water for injection, q. s. to 3 ml Preparation: as described in Example 9, to be preferably used by intramuscular route. Example 14 Composition A vial contains: Bisodium etidronate 100 mg soy bean lipids 330 mg egg yolk phospholipids 39.6 mg glycerol 74.25 mg water for injection, q. s. to 3.3 ml

Preparation: according to Example 9. Example 15 Composition

A vial contains: Sodium alendronate 10 mg soy bean lipids 300 mg egg yolk phospholipids 36 mg glycerol 67.5 mg benzyl alcohol 35 mg water for injection 3 ml Preparation: according to Example 9, to be preferably used by intramuscular route. Example 16 Composition A vial contains: Bisodium risedronate 30 mg soy bean lipids 1000 mg soy bean phospholipids 120 mg glycerol 225 mg water for injection, q. s. to 10 ml

Preparation: according to Example 9, to be preferably used by intravenous route. Example 17 Composition

A vial contains: Bisodium risedronate 5 mg soy bean lipids 300 mg soy bean phospholipids 36 mg glycerol 67.5 mg benzyl alcohol 35 mg water for injection, q. s. to 3 ml Preparation: according to Example 9, to be preferably used by intramuscular route. Example 18 Composition A vial contains: Bisodium zoledronate 4 mg soy bean lipids 500 mg egg yolk phospholipids 60 mg glycerol 112.5 mg water for injection, q. s. to 5 ml

Preparation: according to Example 9.

Example 19

A vial contains: Bisodium tiludronate 100 mg soy bean lipids 500 mg egg yolk phospholipids 60 mg glycerol 112.5 mg water for injection, q. s. to 5 ml

Preparation: according to Example 9.

Example 20

Composition

A vial contains: Bisodium ibandronate 22 mmgg soy bean lipids 300 mg soy bean phospholipids 36 mg glycerol 67.5 mg benzyl alcohol 35 mg water for injection, q. s. to 3 ml

Preparation: according to Example 9. Example 21

Local tolerance of the formulation of the invention

The test has been carried out evaluating the response to the local painful stimulus induced by the administration of the formulation in the rabbit (licking test).

Male rabbits weighing 3.2-3.6 kg (n=5), shaven in the dorsal area, were treated by intradermal injection in the right and left area, respectively with 200 μl of 3% solution of clodronate in water (Control) and in lipid emulsion according to Example 7 (Test). The pH of both solutions was adjusted to pH 5.5. The pain induced by the injected solutions was directly proportional to the number of responses of the animal, reacting to pain by licking the area of injection. The rabbits were kept under examination for 30 minutes, determining the response to the painful stimulus as shown in the following Table.

*P<0.05 (t Student Test) It is then evident that the Test preparation of the invention is clearly and significantly better tolerated than the water Control solution. After 24 hours from treatment, no lesion was evidenced at the site of intradermal injection of Test solution, while at the site of Control solution inflammation and oedema were still present. Example 22

Tolerance by intramuscular route of the formulation of the invention The test has been carried out evaluating the local damage induced by the intramuscular administration of the product in the rat. Two groups of male rats weighing 250- 280 g (n=8) were treated by injection into the thigh muscular area, by means of a 0.45 x 13 mm needle, of 1 ml/kg respectively of 3% clodronate solution in water (Control group) and in lipid emulsion according to Example 7 (Test group). The pH of both solutions was adjusted to pH 5.5. After 24 hours from treatment, the animals were sacrificed under ether anaesthesia and the treated muscle was sectioned to evidence the site of injection.

The eventual damage induced was evaluated through the following rating scale: 0 = normal or mild hyperaemia; 1 = hyperaemia with haemorrhagic area < 1 cm; 2 = hyperaemia with haemorrhagic area > 1 cm; 3 = haemorrhagic area and haematoma > 1 cm; 4 = diffused haematoma >2 cm. The results are reported in the Table.

*P < 0.05 (t Student Test) It results that the damage induced by the invention lipid formulation is quite lower, as confirmed by statistical significance, in comparison to that induced by the reference control aqueous formulation. Example 23

Tolerance by intravenous route of the formulation of the invention

The test has been carried out by evaluating the venous tolerance to the repeated intravenous administration in the rabbit.

Male rabbits weighing 2.7-3.1 kg were treated daily with intravenous injection into the marginal vein of the left and right ear respectively, of 1 ml 3% clodronate solution in water (Control) and in lipid emulsion according to Example 7 (Test). The pH of both solutions was corrected to pH 5.5. The period of injection was 90 seconds and treatment was repeated for 3 running days.

At 24 hours following each treatment, before the next one, the site of injection was checked, evaluating the local damage brought about by means of the following arbitrary rating scale: 0 = no damage; 1 = mild inflammation; 2 = inflammation / hyperaemia; 3 = hyperaemia / necrosis (0-2 mm); 4 = necrosis (3-5 mm). Results are reported in the Table.

The left ear, treated with the aqueous solution, showed evidence of inflammation and hyperaemia already after the first injection, with progressive worsening toward thrombus formations and evident necrotic signs after 3 days, making it impossible further administrations.

The right ear, treated with the lipid emulsion, was free from evident damages, only showing mild inflammation at the site of injection, substantially due to the mechanical action of the needle. It was therefore concluded that the formulation of the invention was clearly better tolerated by the vasal endothelium in comparison with the aqueous reference formulation.

Claims

CLAIMS 1. A pharmaceutical formulation comprising a compound of the bisphosphonate class in a solubilizing/dispersing vehicle comprising a pharmaceutically acceptable water emulsion of lipids and/or phospholipids.

2. A pharmaceutical formulation according to claim 1, wherein the compound of the bisphosphonate class is selected from the group consisting of a bisphosphonic acid and/or a pharmaceutically and pharmacologically acceptable salt with a monovalent cation or an in vitro or in vivo precursor thereof.

3. A pharmaceutical formulation according to claim 1 or 2, wherein the compound of the bisphosphonate class is under an anhydrous or hydrate -crystalline, amorphous or polymorphous- form, as a racemate, enantiomer or diastereoisomer.

4. A pharmaceutical formulation according to any of the previous claims, wherein the compound of the bisphosphonate class has the following general formula (I): ₂(HO)OP- CRιR₂-PO(OH)₂, wherein Ri and R₂, which can be equal or different between them, represent hydrogen; halogen; hydroxyl; substituted or unsubstituted amino, thio, -C₃ alkyl or Cι-C₆ aminoalkyl groups; or a pharmaceutically acceptable salt or in vitro or in vivo precursor thereof.

5. A pharmaceutical formulation according to the previous claim, wherein Ri and/or R₂ represent chlorine; an amino group enclosed in a heterocycle; a C1-C3 alkyl substituted with an isolated or condensed homo- or hetero- cycle, the latter cycle containing 1 or 2 hetero-atoms.

6. A pharmaceutical formulation according to the previous claim, wherein the hetero- atoms in the heterocycles are nitrogen atoms.

7. A pharmaceutical formulation according to any of the previous claims, wherein the compound of the bisphosphonate class is a bisodium salt.

8. A pharmaceutical formulation according to any of the previous claims, wherein the compound of the bisphosphonate class is selected from the group consisting of bisodium etidronate, clodronate, risedronate, zoledronate, pamidronate, alendronate, neridronate, ibandronate, olpadronate, icadronate, tiludronate.

9. A pharmaceutical formulation according to any of claims 1-6, wherein the compound of the bisphosphonate class is clodronic acid or bisodium clodronate.

10. A pharmaceutical formulation according to any of the previous claims, wherein the compound of the bisphosphonate class is in an amount from 0.1 mg to 500 mg.

11. A pharmaceutical formulation according to any of the previous claims, wherein the compound of the bisphosphonate class is in an amount from 1 mg to 300 mg.

12. A pharmaceutical formulation according to any of the previous claims, wherein the volume of the formulation ranges from 0.5 to 500 ml.

13. A pharmaceutical formulation according to any of the previous claims, wherein the volume of the formulation ranges from 5 to 10 ml.

14. A pharmaceutical formulation according to any of the previous claims, wherein the volume of the formulation ranges from 1 to 5 ml.

15. A pharmaceutical formulation according to any of the previous claims, wherein the solubilizing/dispersing vehicle is an oil in water emulsion.

16. A pharmaceutical formulation according to any of the previous claims, wherein the emulsion comprises lipids and/or phospholipids of animal, vegetable, synthetic or semi- synthetic origin, or a mixture thereof.

17. A pharmaceutical formulation according to any of the previous claims, wherein the lipids are selected from the group consisting of mono-, di-, or tri-glycerides, or a mixture thereof.

18. A pharmaceutical formulation according to any of the previous claims, wherein the lipids are selected from the group consisting of soy bean, olive or fish oils, or a mixture thereof.

19. A pharmaceutical formulation according to any of the previous claims, wherein the lipids are in an amount from 1 to 25%.

20. A phannaceutical formulation according to any of the previous claims, wherein the lipids are in an amount from 10 to 20 %.

21. A pharmaceutical formulation according to any of claims 1-16, wherein the phospholipids are selected from the group consisting of soy bean lecithin or egg yolk lecithin, or a mixture thereof.

22. A pharmaceutical formulation according to the previous claim, wherein the phospholipids are selected from the group consisting of distearoilphosphatidylcholine, dimyristoilphosphatidylcholine, dimyristoilphosphatidylglycerol, phosphatidylethanolamine, phosphatidylserine, phosphatidylinositol, phosphatidylcholine, or a mixture thereof.

23. A pharmaceutical formulation according to claims 21 or 22, wherein the phospholipids are in an amount from 0.05 to 10%.

24. A pharmaceutical formulation according to any of claims 21-23, wherein the phospholipids are in an amount from 0.1 to 5%.

25. A pharmaceutical formulation according to any of the previous claims, wherein the lipids and/or phospholipids are hydrogenated.

26. A pharmaceutical formulation according to any of the previous claims, comprising a pharmaceutically acceptable excipient and/or adjuvant. - 27. A pharmaceutical formulation according to the previous claim, wherein the excipient and/or adjuvant is selected from the group consisting of sugars, polyalcohols, dispersing/suspending agents, preservatives, ionic or non-ionic surfactants, basic or neutral or acid buffers, co-solvents, stabilizers and antioxidants. 28. A pharmaceutical formulation according to the previous claim, wherein the sugar is lactose, glucose, saccharose, or maltose; the polyalcohol is glycerol, mannitol or xilitol; the dispersing/suspending agent is povidone; the preservative is benzyl alcohol or a paraben; the ionic or non-ionic surfactant is sodium laurylsulfate, sodium deoxycholate, a polysorbate, Cremophor; the basic or neutral or acid buffer is an alkaline carbonate or bicarbonate, phosphate, or TRIS buffer. 29. A pharmaceutical formulation according to the previous claim, wherein the lipids and/or phospholipids have a particle size lower than about 5 microns. 30. A pharmaceutical formulation according to the previous claim, wherein the lipids and/or phospholipids have a particle size lower than about 1 micron. 31. Use of a pharmaceutical formulation according to any of the previous claims for the preparation of a medicament for the treatment of pathologies sensitive to the action of the compounds of the bisphosphonate class. 32. A method for the treatment of pathologies sensitive to the action of the compounds of the bisphosphonate class in a mammal in need thereof comprising administering to the mammal a therapeutically effective dose of the pharmaceutical formulation according to any of claim 1-30, which ranges from about 0.002 to 10 mg/kg of body weight per day. 33. A method according to the previous claim, wherein the mammal is parenterally administered the pharmaceutical formulation as defined in any of claims 1 to 30, either daily or intermittently, or each other day, each 7, 10, 14 days, each month, until discontinuous use each 6-12 months. 34. A method according to the previous claim, wherein the mammal is administered a dose of the pharmaceutical formulation as defined in any of claims 1 to 30, either intravenously or intramuscularly. 35. A method according to the previous claim, wherein the mammal is intramuscularly administered a dose of the pharmaceutical formulation as defined in any of claims 1 to 30.