MXPA99005478A - Complexes use of cationic liposomes and polideoxyribonucleotides as medicaments - Google Patents

Abstract

La invención se refiere al uso de medicamentos, específicamente antiinflamatorios, de complejos formados por liposomas catiónicos y polidioxiribonucleótidos que tienen un peso molecular en la escala de 7000- 60000 Da que se obtienen mediante depolimerización de losácidos nucleicos, en donde en dichos complejos los polideoxiribonucleótidos se localizan en la superficie externa de liposoma.

Description

USE OF COMPLICATIONS BETWEEN CATIONIC LIPOSOMES AND POLIDEOXIRIBONUCLEOTIDES AS MEDICINES DESCRIPTIVE MEMORY The present invention relates to the use as medicaments of complexes formed by cationic liposomes and polideoxyl-ring nucleotides. More specifically, the present invention relates to the use of the aforementioned complexes, which possess considerable stability in time as drugs having anti-inflammatory activity. It is well known that liposomes can be used as vehicles for the routine administration of drugs. Said liposomes are administered by intravenous, subcutaneous, intramuscular injection or by infusion. As regards the structure of the complexes between liposomes and DNAs, it is known that oligodeoxyribonuleotides and plasmid DNAs can be linked by an ionic bond to the external surface of cationic liposomes (CF Bennet et al., Mol. , 1023-1033, 1992; Xlang Gao and others Biochem Biophys, Res Comm, 179, 280-285, 1991). However, there is no indication of the stability over time of said complexes and their use as anti-inflammatory drugs. It is also known from patent application WO 97/04787 that when the oligonucleotides have a chain length of between 8 and 50 nucleotides, they can be understood in the liposomes. Nor is information given in this reference about the stability of complexes over time. Complexes have been described with liposomes and polideoxyribonucleotides having a molecular weight of 16,000 Da, obtained by nucleic acid depolymerization, wherein said polymers are contained within the lipid vesicle (Gursoy et al., Pharmazie 48, (1993) H. 7, 559-560). The same can be repeated of the above for WO 97/04787. It is also known that liposome complexes with oligonucleotides and polideoxyribonucleotides have the property of considerably increasing the pharmacological activities of these latter substances (Bennet et al., Gursoy et al., Supra, A. Colige, Biochemistry 1993, 32, 7-11). . However, the tests carried out by the applicant have shown that these prior art complexes can not be used as therapeutic agents because, when suspended in aqueous media, as requested for their administration, they very quickly lose their activity in the time. In addition to the above, in such complexes the cationic components of the liposome, such as for example stearylamine and the quaternary ammonium surfactants, can be potentially toxic agents which can cause toxic side effects. The degradation of the complex is also evident, since the physical appearance of the aqueous phase changes over time, becoming opalescent (initial emulsion) to final limpid, with the formation of a precipitate.

Polideoxyribonucleotides, and specifically those known as defibrottid, are well known as medicaments having profibrinolytic activity (R. Pescador et al., Thromb Res. 30: 1-11, 1983), antithrombotic-thrombolytic (R. Niada et al., Pharmacol Res. Commun. 14 (10), 949-957 1982) Antihypertensive (F. Trento et al., XXVII Congr. Naz. Soc. It. Pharmacology Torino 25-29 September 1994, Abstract Book page 703), anti-ischemic, cytoprotective (G. Rossonl et al J. Cardiovasc Pharmacol 27, 680-685 1986) and anti-inflammatory activity (R.Scalla, Meth.Find.Exc. Clinical Pharmacol. 18 (10) 669-676 1996). Daily doses vary from 600 to 1200 mg. Said pharmacological activities of the substance are essentially referable to its property to locally release the therapeutically effective amounts of endogenous prostacillin from the vascular endothelium (ref.R. Níada et al., Supra, C. Thiemermann et Alili, Am. J. Cardiol. 1985-982). It has surprisingly and unexpectedly been discovered by the applicant that it is possible to prepare complexes of liposomes and polideoxyribonucleotides having a high activity that lasts over time, devoid of any toxic side effects. The foregoing is faced with the use of aqueous emulsions containing the complexes of the invention for subsequent treatments, for one or more days, and also for long-term administrations, such as infusions.

It is therefore an object of the invention to use as medicaments, specifically as antiinflammatories, complexes formed by cationic liposomes and by polideoxiribonucleotides having a molecular weight in the range of 7,000-60,000, preferably 10,000-60,000, most preferably 15,000- 60,000 Da, obtainable by depollmerization of nucleic acids, wherein the polideoxiribonucleotides are located on the outer surface of the liposome. Said liposome complexes are characterized in that their solutions, by adding aliquots of a solution of cetylpyridinium chloride, form an amount of a precipitate with said quaternary ammonium ion which is different from that which is obtained by treatment under the same conditions of a solution of liposome complexes of the same polideoxyribonucleotides and cationic liposomes wherein the polideoxiribonucleotides are located within the liposome. In a preferred embodiment of the invention, the polideoxyribonucleotides are defibrotides. Therefore, according to the present invention, it is also possible to reduce the daily dose to be administered to the patient, without affecting the effectiveness of the therapy. Liposomes are lipid vesicles, which are formed in the aqueous phase, and are generally made up of phospholipids. Said compounds in the presence of water and an insoluble organic solvent form a spherical shell whose wall is a double layer, wherein the polar portion of the molecule (hydrophilic) is on the outer side of the liposome and the lipid portion (hydrophobic) is find inside the double layer. The gallbladder in this case is called monolamellar. There are also multilamellar liposomes, which are composed of more lipid layers. Polideoxyribonucleotides having a molecular weight in the range of 15,000-60,000, which are used in complexes with liposomes according to the present invention, are obtained by extraction and subsequent depolymerization of high molecular weight nucleic acids. The extraction of high molecular weight nucleic acids can be carried out as described in USP 3,770,720, incorporated herein by reference. It is possible to obtain polideoxyribonucleotides with molecular weight in the range of 15,000-30,000 by the application of nucleic acid depolymerization, as described in USP 4,985,552, incorporated herein by reference. The Applicant has realized that it is also possible to obtain polymers having a molecular weight in the range of 30,000-60,000, using the same process conditions of USP 4,985,552, stopping depolymerization with the value of reversible hyperchromicity, as define in Methods in Enzymol. Vol. Lil pag. 708-712, which is comprised between 20 and 40% (with reference to the absorption value of the reversible hyperchromicity of the sample is not naturalized), or, stopping the depolymerization when the value of the reversible hyperchromicity is greater than or equal to 3 to obtain polideoxiribonucleotides having a molecular weight greater than or equal to 70,000. Reversible hyperchromicity is the parameter by which the progress of depolymerization is followed. The polideoxiribonucleotides referred to form the complex with the cationic liposome are those known as defibrotides (D.C.I.), having a molecular weight in scale of 15,000-30,000 (\ nformations Pharmaceutiques O.M.S. No. 4, vol./1987 page 272). The main lipid components of the liposomes of the invention are phosphatidylcholine or phosphatidylethanolamine, which can be combined in the liposome with other lipids, as described in R.R.C. New volume "Liposomes, a practica! Approach" IRL Press 1994, incorporated herein by reference. Preferred associated lipids are ergosterol and cholesterol. One or more antioxidants, selected from the known ones and which are listed in the same reference previously mentioned, can be added to the composition. The preferred antioxidant is alpha-tocopherol. To the liposomes of the invention are added cationic surfactants, containing one or more mono-, disubstituted amine groups, or quaternary ammonium groups. Said quaternary ammonium groups contain one or more aliphatic chains with a number of carbon atoms ranging from 8 to 22. Quaternary ammonium surfactants having aliphatic chains with 18 carbon atoms are preferred.

The molar ratio between the total amount of the liposome lipids and the cationic surfactant varies from 10: 0.05 to 10: 3, preferably 10: 1. When there is a second different lipid together with phosphatidylcholine (or phosphatidylethanolamine), the internal molar ratios between each of the lipids and the surfactant (phosphatidylcholine (or phosphatidylethanolamine): second lipid: surfactant) varies from 9: 1: 0.05 to 7: 3: 3, preferably 8: 2: 1. The weight ratio between the amount of liposome and that of the active principle (polideoxyribonucleotides) ranges from 10: 2 to 10: 0.1, preferably 10: 1. The preparation of the cationic liposome complexes used in the present invention It can be carried out as described by DC Litzinger, Biochim. Biophys. Acta 1281 139-149, 1996, or the new volume of R.R.C. aforementioned. In particular, a method usable for preparing the complex of the present invention comprises the following steps: a. liposome preparation using the solvent reversed phase evaporation method, ref. Szoka P. and others. Proc. Nati Acad.Sci. USA 75 4194 1978): 4 parts of organic phase, which may be polar (ie linear or branched C-α-C lower aliphatic alcohols) or apolar (i.e. dialkyl ethers of linear or branched dC, such as for example , diethyl ether, partially chlorinated C2 hydrocarbons, preferably chloroform), where the lipids, the cationic surfactant and the antioxidant are solubilized, with a part of water, the biphasic system thus obtained is subjected to sound treatment. 0 ° C for 5-20 minutes, the organic phase is then evaporated at room temperature under reduced pressure, thereby obtaining an emulsion, b. flowing said emulsion, according to the technique described on pages 52,54 of the new volume of R.R.C., through a polycarbonate membrane having a pore diameter ranging from 100 to 600 nm, preferably 400 nm; the passage is repeated at least three times, to thereby obtain an average vesicle diameter comparable to that of the pores of the membrane, c. lyophilize the aqueous emulsion, after the addition of an aqueous solution of a lyophilizing adjuvant, for example monosaccharides such as sucrose, sorbitol, mannitol, fructose, or polysaccharides such as dextrans, maltodextrins having different molecular weight, so that the adjuvant is in excess of at least 7 times with respect to lipids. Preferably the excess is comprised between 10 and 15 times, d. preparation of the final emulsion for pharmaceutical use by adding a sterile isotonic aqueous solution of polydeoxyribonucleotides to the container containing the lyophilized emulsion in a sterile medium, with stirring. An emulsion containing a liposome complex is formed wherein the polideoxyribonucleotides are linked with an ionic bond to the outer wall of the liposome. Alternately, a sterile isotonic solution is added to the container containing the lyophilized liposomes and the emulsion obtained in this way is mixed in a sterile medium with the solution containing the active ingredient. The stability of the liposomes of the invention has been evaluated by testing the pharmacological activity immediately after preparation of the emulsion and then on day 30 of conditioning under sterile conditions at 25 ° C in the dark. The emulsion containing the liposome complex of included polydeoxynibonucleotides (Gursoy et al., See above) was subjected to the same test and used as a comparative formulation. The Applicant has also discovered that the complexes of the present invention can be used in the same way as antihypertensive and atythrombotic agents that have a high activity in time, without side toxic effects. The pharmacological activity has been determined in the following experimental models. Anti-inflammatory activity (Miyasaka et al., Eur. J. Pharmacol. 77 229-236 1982). Arterial hypertension (F. Trento et al., See above). Antithrombotic activity (R. Niada et al., Thromb. Res. 23 233-246, 1981). In the experiment that is related to the anti-inflammatory activity, the amount of myeloperoxidase present in the polymorphonucleates obtained from the animal ployual exudate has been tested. The amount of enzyme is directly proportional to the inflammation produced. The results are expressed as percentage in variation of the amount of myeloperoxides (MPO) with respect to the controls, determined with the formula: MPOrratado "MPOcontrols MPOcontrols In the hypertension model, the parameter used to determine the activity was the blood pressure that was monitored up to 30 minutes from the treatment with L-NAME, the inhibitor of endogenous nitric oxide release. In the model of antithrombotic activity, carotid temperature has been monitored up to 60 minutes after the induction of the local endothelial lesion. The results have been expressed as percentage in variation of the area under the curve (? AUC%) obtained with the sample tested with respect to that of the controls, by means of the following relationship: AREA treated "Areacontroles Areacontroles The results obtained, reported respectively in tables II and II, show that the complex between liposomes and polydioxyribonucleotides according to the present invention is stable in time, unlike the comparative formulation. According to the present invention, it is therefore possible to administer to the patient a lower amount of the active principle while maintaining the therapeutic effect without change. It is also possible to use the same complex emulsion, suitably formulated and with a suitable concentration of active principle, for a whole cycle of therapy as required in the aforementioned pathologies. It is also known that polydioxyribonucleotides known as defibrotide have an antithrombotic activity (R. Niada, Pharmacol. Res. Comm., See above), anti-ischemic, cytoprotective (C. Thiermemann, see above), anti-inflammatory activity ( G. Rossoni, J. Cardiovasc Pharmacol., See above) and in arteroesclerosis (P. Lober et al., Atherosclerosis 80, 69-79 1989). These activities refer to the local release of endothelial prostacyclin in the bloodstream in therapeutically effective amounts. It has been discovered by the applicant that the liposome-polydioxyribonucleotide complexes described in the present invention can be used for pathology therapy, the treatment of which requires sustained release of endothelial prostacyclin. Pharmaceutical formulations containing the cationic liposome-polidioxiribonucletides include the usual carriers and excipients. Said formulations may be in the form of sterile and apyrogenic emulsions, or di-silkylises, stored in sterile containers, to dissolve extemporaneously in sterile aqueous solvents. In the latter case, it is preferred that the liposome lyophilisate be stored separately and that the polydioxyribonucleicides be dissolved in the aqueous sterile solvent to be added to the liposomes. As sterile aqueous solvents, sterile isotonic solutions containing conventional pH regulators (citrates, phosphates) can be used in conjunction with known preservatives. The administration routes of the emulsion containing the complex of the invention are those parenteral, that is, by intravenous, intramuscular, subcutaneous, and infusion injection. The amount of active ingredient contained in the preparation varies from 1 to 20 mg / ml of polydioxyribonucleotide. The daily doses of polydioxyribonucleotide administered with the liposome complexes vary from 10 to 200 mg, preferably from 20 to 120 mg. The following examples are intended to clarify the content of the present invention and are not considered as a limitation on the scope thereof.

EXAMPLE 1 Preparation of polydioxyribonucleotide liposomes.

The preparation of the liposomes used in the present invention is carried out in accordance with the method of reversing phase evaporation of the solvent. 100 mg of soy phosphatidylcholine (Phospholipon® 90-Natterman Phospholipido GmbH), dioctadecyldimethylammonium bromide (abbr DIDAB-Fluka Chemis AG) and 0.1% w / w alpha-tocopherol (Fluka Chemie AG) are dissolved in diethyl ester. The phosphatidylcholine and the cationic surfactant are mixed in a molar ratio of 10: 1. To the organic phase, bidistilled water is added in a ratio of four parts of organic phase / 1 part of water, obtaining in this way a W / O emulsion. In the emulsion, a sound treatment at 0 ° C is carried out for 10 minutes by the use of a Branson 2200 sound emitting batch. The ether is then removed by evaporation at reduced pressure until the aqueous liposomal system is obtained , which then is caused to flow through the polycarbonate (nucleoporous) membranes having a pore diameter of 0.4 μm. Said passage through the membrane is repeated three more times. An amount of mannitol equal to 10 times the lipid weight is added and the suspension is lyophilized. 50 mg of polydioxyribonucleotide having a molecular weight of 28000, obtained by polymerization according to the USP document 4,985,552, are dissolved in 5 ml of isotonic physiological solution. The lyophilisate obtained above is dissolved in 5 ml of bidistilled water. The two aqueous phases are mixed and stirred. In the emulsion obtained in this way, the concentration of the forphatidylcollna is 10 mg / ml and that of the polydioxyribonucleotide is 50 mg / ml.

EXAMPLE 2 (COMPARATIVE) Preparation of polydioxyribonucleotide liposomes according to the prior art (Gursoy et al., Pharmazie 48 (19-93) H 7 559-560) having the polydioxyribonucleotide comprised in the liposome. The same organic phase of Example 1 with the same components mentioned above is dried separately in a container. An aqueous solution of a polydioxyriboucleotide having a molecular weight of 16000 is added, prepared as the polydioxyribonucleotide solution of the previous example. The liposomal vesicles that comprise the active principle are obtained by sound treatment. The concentrations of phosphatidylcholine and polydioxyribonucleotide are the same as those in the complex of example 1.

EXAMPLE 3 Demonstration of the formation of the polydioxyribonucleotide-liposome complex of Example 1 by electrophoretic method The electrophoresis is carried out on a 3% agarose gel containing 0.5 μg / ml of etldium bromide as the fluorescence agent. The electrophoretic system consists of a small electrophoretic chamber containing a layer of gel with a thickness between 1-3 mm, to which an electric field of 50 mV is applied. In the gel, respectively, in 6 separate zones near the negative pole, 20 μl of the solution of Example 1 (5 mg / ml concentration of polydioxyribonucleotides), and of solutions containing the polydioxyribonucleotide alone, at concentrations of 4, 3 are seeded respectively. , 2, 1, 0.5 mg / ml. The electric field is applied for 40 minutes. The polydioxyribonucleotide moves from the sown area to the positive pole. At the end of the electrophoretic function, the diagarose is stained with ethidium bromide. The liposome complex does not show any coloration. In the gel the bands corresponding to the seeds of the polidioxiribonucleotide solutions are shown, whose intensity is proportional to the amount sown.

EXAMPLE 4 Comparison of the stability of the liposome-polydioxyribonucleotide complex obtained according to example 1 of the complex in which the polydioxyribonucleotide is contained within the liposome (comparative example 2), by evaluating the anti-inflammatory activity of the polydioxyribonucleotide in rats treated with samples of solutions of said complexes freshly prepared and with samples of said solutions conditioned for 30 days at 25 ° C in closed containers, in the dark. Spregue Dawley male rats weighing 250-270 g were used. Three groups were formed, each group of 18 animals, and each of the groups was administered intravenously, respectively, one of the following solutions in the doses mentioned: 1.- Control group: Physiological solution, at 2 ml / kg. 2.- Group treated with the liposome-polidioxiribonucleotide complex (ref Ex.l): physiological solution containing the complex in equal amounts at a concentration of polydioxyribonucleotide from 1 mg / ml to 2 mg / kg. 3.- Group treated with the liposome-polydioxyribonucleotide complex according to A. Gursoy et al. (See above): physiological solution containing the complex in equal amounts at a concentration of polydioxyribonucleotide of 1 mg / ml at a dose of 2. mg / kg. 30 minutes after the treatment, under gentle ether anesthesia, pleuritis was caused in the animals by administration by intrapleural route of 0.5 ml of 1% w / v of carrageenan physiological solution and 50 ml of water per os. After 6 hours the animals were sacrificed. The pleural exudate was recovered by a syringe, and the polymorphonucleato neutrophil leukotl (PMN) content was determined by the myeloperoxldase enzyme (MPO) assay, which is the enzyme characteristic of these cells. The assay was carried out as described in -Schierwagen C et al. J. Pharmacol. Methods 23 179 1990. Samples of exudate were stirred and then 0.2 ml was added to 4.8 ml of 0.5% w / v of regular solution at its pH of H (hexadecyltrimethylammonium bromide). The samples were then frozen at -80 ° C to cause the cell to break, thawed and then subjected to 80 wats of sound treatment for 1 minute. The preparations were heated at 60 ° C for 2 hours to degrade myeloperoxidase inhibitors and subsequently centrifuged at 11,800 g for 5 minutes at 4 ° C. Before proceeding with the spectrophotometric enzyme assay (wavelength of 650 nm), the samples were diluted with HTAB solution to place the reading values on the scale of the standard curve obtained by using the pure MPO enzyme. The results are expressed as a percentage variation with respect to the MPO quantity found in the controls and are reported in the following table I. The evidence in the table that the anti-inflammatory activity of the two preparations at zero time is substantially the same and after 30 days the activity of the preparation according to the invention does not differ significantly from the initial value, while the preparation containing the liposomes according to the comparative example shows a reduction of activity of 70% with respect to the initial value. At the same time it was observed that the latter preparation was degraded, since the aqueous phase appeared limpid and a precipitate was present that could not be resuspended. The animals treated with this preparation showed obvious signs of pain and pronounced dyspnea.

EXAMPLE 5 Comparison of the stability of the liposome-polydioxyribonucleotide complex obtained according to example 1 from the complex where the polydioxyribonucleotide is contained inside the liposome (comparative example 2), by evaluating the antihypertensive activity of polidioxiribonucleotide in rats, with induced hypertension by inhibiting the release of endogenous nitric oxide (NO), administered with the samples of solutions containing the above complexes freshly prepared and with samples of the same solutions conditioned at 25 ° C for 30 days in closed containers in the dark Male Sprague Dawley rats weighing 250 + 20 g, not rushed, are anesthetized with ethyl urethane. The catheters were inserted respectively into the left carotid artery, to record the mean arterial blood record (MABP), and in the right jugular vein, for administration of the tested compositions. The trachea was probed and the animal's body temperature was maintained at 37 ° C. The MABP was recorded continuously in the experiment. Heparin (500 U.l. / Kg i.v.) was administered to prevent blood coagulation in the recording system. After 30 minutes, the rats were randomized into homogeneous groups. The treatment with the compositions or the placebo was carried out by means of a bolus, immediately followed by the perfusion. After one hour of starting the infusion, all animals received an intravenous bolus of L-NAME (10 mg / kg). The perfusion lasted 30 minutes after the injection of L-NAME.

The pressure changes induced by the compositions are expressed as an area under the curve (AUC) in the range of 30 minutes, followed by the L-NAME treatment. In the experimental model under consideration, the animals were divided into 4 groups (6 animals per group), each of them treated intravenously with a bolus of 1 ml / kg, immediately followed by an infusion of 2 ml / kg / h, as explained below: 1.- Control group (CTR): physiological solution 1 ml / kg of bolus + 2ml / kg / hour in perfusion. 2.- Group treated with a bolus of a polydioxyribonucleotide of 28,000 moles by weight in a physiological solution at a concentration of 10 mg / ml, in the dose of 10 mg / kg (bolus) + 20 mg / kg / h in perfusion. 3.- Group treated with a bolus of the liposome-polydioxyribonucleotide complex of the invention in a physiological solution at a concentration of polydioxyribonucleotide of 5 mg / ml, in the dose of 5 mg / kg (bolus) + 10 mg / kg / h in perfusion. 4.- Group treated with a bolus of the liposome-polydioxyribonucleotide complex according to comparative example 2 in a physiological solution at a concentration of polydioxyribonucleotide of 5 mg / ml, in the dose of 5 mg / kg (bolus) + 10 mg / kg / h in perfusion. The pharmacological activity determined by using samples of freshly prepared solutions containing the aforementioned liposome complexes, and samples of the same solutions stored in the closed containers at 25 ° C in the dark, is reported in Table II. The results show that while at time zero the two preparations have almost the same antihypertensive activity, after 30 days, the activity of the preparation according to the prior art is reduced to approximately 70% in comparison with the starting value correspondent. The animals treated with this preparation showed evident signs of pain with marked dyspnea.

EXAMPLE 6 Comparison of the stability of the liposome-polydioxyribonucleotide complex obtained according to Example I with that of the complex where the polydioxyribonucleotide is contained inside the liposome (comparative example 2), by evaluating the antithrombotic activity of the polydioxyribonucleotide in rats, treated with samples of solutions containing the above complexes freshly prepared and with samples of the same solutions conditioned at 25 ° C for 30 days in closed containers in the dark. The male Sprague Dawley rats weighing 200-230 g, rushed for 16 hours, were anesthetized with urethane (1.25 g / kg i.p.).

The right carotid artery and the left jugular vein of the animals were then isolated. A bipolar electrode (lesion production device 3500 Ugo Basile - Comerio, Varese) was placed in the right artery and, at a distance of 0.5 cm, a thermosensitive probe was connected to a polygraph. A catheter was inserted into the vein to administer the preparations. After 15 minutes of stabilization, the temperature of the carotid was recorded continuously from 5 minutes before to 60 minutes after the induction of the endothelial lesion by the electrode. This allowed to indirectly determine the formation of endoluminal thrombi by correlation between the decreasing temperature of the container and the reduction of blood flow. The endothelial lesion was caused by a series of 5 electrical stimuli. The stimuli at intervals of 1 minute between them were such that the impedance measured in the injured artery was 10 mA. The impedance was measured with a tester and regulated for each animal during the first 30 seconds of the stimulation, and required the applied voltage of approximately 30 volts. The temperature of the carotid was determined immediately before the electrical stimulation (base value) and at constant intervals of time (5, 10, 15, 30, 45 and 60 minutes) after the stimulation. The groups were each formed by 10-12 rats. All the treatments were carried out as intravenous boluses that were administered 5 minutes before the start of the electrical stimulation.

The groups were the following: 1.- SHAM control group, where the animals were operated and monitored as described above, but did not undergo electrical stimulation. 2.- Control group, treated with physiological solution (1.5 ml / kg i.v.). 3.- Group treated with the liposome-polidioxiribonucleotide complex (ref 1 ex: 1): physiological solution containing the complex in an amount equal to a concentration of polydioxyribonucleotide of 5 mg / ml; administered dose: 7.5 mg / kg. 4.- Group treated with the liposome-polydioxyribonucleotide complex according to A. Gursoy and others (see above): physiological solution containing the complex in equal amounts at a polydioxyribonucleotide concentration of 5 mg / ml; administered dose: 7.5 mg / kg. The activity was determined at the time of the preparation of the solutions with the complexes and after 30 days of conditioning said solutions at 25 ° C in the dark. The results were reported in table III. From the table it is observed that while the antithrombotic activity of the two preparations at time zero is substantially comparable, after 30 days, the activity of the preparation according to the prior art is reduced by about 70% in the comparison with the corresponding starting value.

EXAMPLE 7 Pharmaceutical formulation, containing the liposomes used in the present invention, for the administration of single dose. A sterile 3 ml bottle containing the lyophilized liposome: phospholipon 90 mg 100 - DIDAB mg 10 alpha-tocopherol mg 0.1 sucrose g 1 Before use add 1 ml of water for injection. Then add in a sterile form the following sterile solution, prefabricated in a disposable 1 ml sterile syringe that is added to the above: polydioxyribonucleotide (ref 1 ex) mg 10 trisodium citrate bihydrate mg 2.5 water for injections and preservatives, enough ml 1 EXAMPLE 8 The extemporaneous pharmaceutical formulation that is used for a whole therapeutic cycle. A sterile 30 ml bottle containing the lyophilized liposome: phospholipon 90 g 1 DIDAB mg 100 alpha-tocopherol mg 1 sucrose g 10 Before use add 10 ml of water for Injection in a sterile form in the bottle. Add to the emulsion prepared in this way the following sterile solution contained in a 15 ml bottle or in a 10 ml disposable prefabricated syringe. polydioxyribonucleotide (ref 1) mg 100 - trisodium dihydrate citrate mg 25 water for injections and sufficient preservatives ml 10 The preparation provides a dose number of 20 mg / die during the five days of therapy.

TABLE I The 30-day stability of the complex according to example 1 (group 2 in the table) compared to that of the liposome-polideoxyribonucleotide complex according to Gursory et al., (Group 3 in the table), evaluated by the anti-inflammatory activity Polidoxyribonucleotide (reduction of myeloperoxidase activity in pleural exudate of rats with carrageenan-induced pleuritis).

TABLE 2 The 30-day stability of the complex according to example 1 (group 3 in the table) compared to that of the liposome-polyideoxyribonucleotide complex according to Gursory et al., (Group 4 in the table), evaluated by antihypertensive activity of the polideoxiribonucleotide.

* The administered dose of polideoxiribonucleótido (10mg / kg bolus + 20 mg / kg / h) is very low to give rise to considerable antihypertensive activity with respect to the controls.

TABLE 3 The 30-day stability of the complex according to example 1 (group 3) compared to that of the liposome-polldeoxyl-ribonucleotide complex according to Gursoy et al., (Group 4) evaluated by the antithrombotic activity of the polideoxyribonucleotides.

Claims (18)

NOVELTY OF THE INVENTION CLAIMS

1. - Complexes formed by cationic liposomes and by polydioxyribonucleotides having a molecular weight on a scale of 7000-6000 Da, preferably 10000-60000 Da, which are obtained by depolymerization of nucleic acids, characterized in that the polydioxyribonucleotides are located on the inner surface of the liposome, for use as a medication.

2. Complexes according to claim 1 for the preparation of medicaments having an anti-inflammatory activity.

3. Complexes according to claim 1 for the preparation of drugs that have an antithrombotic activity.

4. Complexes according to claim 1 for the preparation of medicaments having antihypertensive activity.

5. Complexes according to claim 1 for the preparation of medicaments for the therapy of pathologies, whose treatment requires a sustained release of the endothelial prostacyclin.

6. Complexes according to claims 1-5 further characterized in that the polydioxyribonucleotide is defibrotide.

7. - Complexes according to claim 6, further characterized in that the polideoxiribonucleotide has a molecular weight in the range of 15,000-30000.

8. Complexes according to claims 1-7, further characterized in that one or more antioxidants, preferably alpha-tocopherol, are added.

9.- Complexes according to claims 1-8 further characterized in that cationic surfactants containing one or more di-substituted amine groups, or quaternary ammonium groups are present, said quaternary ammonium groups contain one or more aliphatic chains with a number of carbon atoms ranging from 8 to 22, preferably said cationic surfactants are quaternary ammonium surfactants having aliphatic chains with 18 carbon atoms.

10. Complexes according to claims 1-9, further characterized in that the molar ratio between the total amount of the lipid of the liposome and the cationic surfactant varies from 10: 0.05 to 10: 3, preferably being 10: 1.

11. Complexes according to claim 10 further characterized in that together with the phosphatidylcholine (or phosphatidylethanolamine) there is a second different lipid and the molar ratio of phosphatidylcholine (or phosphatidylethanolamine): second lipid: surfactant varies from 9: 1: 0.05 to 7: 3: 3, preferably 8: 2: 1.

12. - Complexes according to claims 1-11, further characterized in that the weight ratio between the amount of liposomes and the active principle varies from 10: 0 to 10: 0.1, preferably 10: 1.

13. Complexes according to claims 1-12, which are obtained by a procedure comprising the following steps: a. preparation of the liposome by mixing 4 parts of polar or apolar organic phase, where the lipids, the cationic surfactant and the antioxidant are solubilized, with a part of water, then subjecting the biphasic system obtained to sound treatment at 0 ° C during 5-20 minutes and evaporating the organic phase at room temperature under reduced pressure, thereby forming an emulsion; b. said emulsions flowing through a polycarbonate membrane having a pore diameter ranging from 100 to 600 nm, preferably 400 nm, said step being repeated at least three times, c. leofilizar the emulsion after the addition of an aqueous solution of a leofilizante coadjuvant, so that the amount of said adjuvant is the excess of at least 7 times with respect to that of the lipids, the excess of preference varies from 10 to 15 times, d. preparing the emulsion for pharmaceutical use by adding a sterile sterilized medium under agitation of a dilute sterile isotonic aqueous solution of polydioxyribonucleotides to the container containing the leofilizate, or alternatively adding a sterile isotonic solution to the container containing the lyophilized liposome and from this The emulsion obtained is mixed in a sterile medium with the solution containing the active principle.

14. - Complexes according to claims 1-12, contained in pharmaceutical formulations for parenteral administration.

15. The use of the complexes according to claims 1-14 for the preparation of the medicament having anti-inflammatory activity.

16. The use of the complexes according to claims 1-14 for the preparation of the drug having antithrombotic activity.

17. The use of the complexes according to claims 1-14 for the preparation of the medicament having antihypertensive activity.

18. The use of the complexes according to claims 1-14, for the preparation of the medicament for the treatment of pathologies that require a sustained release of the endothelial prostacyclin.