IL45146A - Process for preparation of derica tives of tetracycline - Google Patents

Abstract

Alkali metal polyphosphate complexes of alpha -6-deoxy-5-hydroxytetracycline are prepared which have the formula (C22H24N2O8)z . (MePO3)x . (HPO3 )y in which Me is sodium or potassium, z = 1 to 5, x = 1 to 5, y = 1 to 5, x + y

Description

present invention is concerned with an improved complexes of which is also called With a view to facilitating the distinction these complexes and those already the complexes described in the present invention will be hereinafter designated as polyphosphate In ra Israeli Patent Application the metal polyphosphate complexes of doxycycline are prepared by reacting each mole of metaphosphorie acid preferabl prepared recently with or moles of sodium or potassium and subsequently with 1 to 5 moles of in a suitable anhydrous reaction inert organic According to the present with freshly prepared methaphosphoric acid doxycycline is first An a suitable reaction inert organic and subsequently with sodium or potassium Fo preparing the polyphosphate complexes of one uses preferably doxycycline The preferred reaction inert medium is dimethyl chloroorm and mixtures sodium and potassium hydroxide added preferably as a ethanolic Once formation of the complex has been the phosphate complex precipitated a such for hexan or a mixture and to this empirical formula when is y and 5 and x to that of the hexametaphosphate sodium complex of prepared Israel according to process described Patent these two complexes in of the fact that the equivalent phosphate complex is many times more soluble than the hexametaphosphate sodium the infrared absorption curves of two complex groups reveal differences in regio and thus that the eomplexation takes place throug different The diferences between the two groups of complexes as far as solubility and curves are concerned are warrant that intramolecular structure is essentially and it can be that the mechahism of as well as the functional groups of involved in eomplexation are not identical in two groups of For purpose of comparison metaphosphoric acid complexes as well as the acid addition salts of doxycycline were in various molar propor tions in accordance with and the double salts of as with doxyeyeline and both as were prepared for differentiation All these complexes and additio salts were of considerable lower solubility in water than the polyphosphate complexes and the blood levels obtained after administration were quantitatively and in duration inferior to those obtained by the polyphosphate All the attempts made with a view to transforming the acid addition salts of into the polyphosphate complexes by treatment with aqueous sodium or potassium hydroxide were The blood levels obtained after oral administration of simple mixtures of doxyeycline hyclate and sodium metaphosphate as well as of doxyeycline base monohydrate and sodium hexametaphosphate were significantly lower tha those obtained after administration of doxyeycline the hexametaphosphate sodium salt does not Improve the absorption of doxyeycline when administered The polyphosphate sodium or potassium complexes of doxyeycline described in the present invention are favourably comparable to the acute and chronic toxicity of doxyeycline and are pharmaceutically The present represents a considerable step in improving the activity and clinical usefulness of doxyeycline by increasing the blood levels when it is administered in the form of metal polyphosphate Other advantages of these complexes are that they are palatable than doxyeyeliae hydrochloride or and form stable or easily stabilized solutions the important therapeutic advantage of the phosphate complexes of doxyeycline lies in the that the functional groups of doxyeycline taking part in the chelation of Ca are blocked in the the well known pharmacological disadvantage due to chelation of the tetracyclines considerabl diminished when administering doxyeycline polyphosphate The examples appearing hereafter illustrate the present without however restricting its scope thei n indicate the blood levels obtained after administration Of the aforesaid polyphosphate may be associated with an other therapeutic with which there no incompatibility or when an association from a clinica point of of freshly metaphosphorlc in 100 of of methanol was added and stirring fo additional 15 of methanol was followed by the of of doxyeycline base the clear solution was maintained at a temperature not exceeding After stirring for 1 of sodium hydroxide dissolved of methanol was added and then stirred for 15 minutes It was then crystallized by adding 400 of After filtering and it yielded 20 of phosphate complex of doxyeycline of the formula Melting point at 1 3 water and in of hydrochloric at 268 and 240 at ram methanol containing concentrated hydrochloric Optical rotation in methanol containing concentrated hydrochloric of the aqueous solution Water content Karl of methanol was added to 250 of chloro containing 20 of metaphosphorlc under stirring at room followed by the addition of of anhydrous dox eyeline base 375 of and of sodium dissolved in of After agitation for 1600 of isopropyl alcohol was added to complete the The precipitate was then washed with isopropyl alcohol and yielding of the polyphosphate complex of dox of form containing of freshly prepared metaphosphorlc and stirred for 30 10 of doxycycline base monohydrate was to the homogeneous solution of the metaphosphorlc Stirring was continued until a clear solution was by the addition 172 of sodium hydroxide dissolved in of starting precipitation Of the After for 15 175 rotation in methanol containing concentrated hydrochloric Wate content Example 2 was but substituting the precipitation 1600 of Isopropyl alcohol by an equal amount of ethanol yielding after drying at the polyphosphate disodium complex o doxycycline as 302 at 268 and 242 at Example 1 was but using of potassium hydroxide dissolved in 6 of of sodium yielding the polyphosphate complex of doxyoycline of the ormula Gelatine capsules containing the polyphosphate monosodium complex of doxycycline prepared according to example equivalent to 100 of and capsules containing hyclate equivalent to 100 of were A dose of two capsules was administered to healthy volunteers in a crossover study so as to determine the serum levels of the complex in comparison to cycllne The study was blind for all 8 volunteers as well as for those who prepared the Blood samples were taken at 3 7 and hours after the administration of 2 x 100 The two phases of the crossover study were realised with one week The serum levels were determined blologically in Table I and II give the data The administration of the polyphosphate monosodium complex of doxycycllne gave an average overall increase of nearly of serum levels in comparison to those obtained after the administration of In a similar the disodlum prepared according to example gave a increase of the 7 For the purpose of the hexametaphosphate sodium complex of doxycycllne was prepared in accordance with the process described in Patent of Kaplan et as 31 of sodium hexametaphosphate was dissolved in of the pH was adjusted to with concentrated hydrochloric and this solution was then added under at room temperature to a solution containing of doxycycllne hyclate in 52 of 1 water and Once the addition was stirring continued for 1 additional The precipitate thus formed was washed with water and then with ethanol When dried at the metaphosphate sodium complex of c cline decom oses at with revious softenin carbonization being complete at 296 at 268 and at Humidity content by the in methanol containing concentrated hydrochloric Solubility in water at the complex is little soluble in methanol and soluble in pH of the aqueous solution infrared absorption curve shows main peaks at After additional amounts crystallize from the with satisfactory thus raising the yield to Gelatine capsules were prepared with the complex above each containing the amount equivalent to 200 of anhydrous doxycycline and control capsules of doxycycline each containing the amount equivalent to 200 of anhydrous doxycycline After administration of 1 capsule per person before the blood levels were The average values obtained 10 volunteers are indicated concentration in exprcssod in doxycycline After hours 8 24 Doxycycline phosphate sodium complex Doxycycline hyclate thus demonstrating that the complex is inferior to both the polyphosphate sodium complex of doxycycline and doxycycline For a further metaphosphoric acid comploxos of doxycycline were prepared according to the process described in Patent of Sieger et as grs of doxycycline base in 65 of methanol was added to a solution containing 4 of metaphosphoric acid in 130 of chloroform and After stirring for 1 it was precipitated by adding isopropyi yielding grs of the metaphosphoric acid plex of doxycycline Melting point with subsequent decomposition at cm327 at 267 and 251 at 349 in methanol containing IS concentrated hydrochloric of the II aqueous suspension Solubility in water at The infrared sorption curve of the suspension in mineral oil mull shows the following main The composition of this complex is n The blood levels obtained after administration this complex were not as prolonged as those obtained after administration of the polyphosphate sodium complex of cycline The metaphosphoric acid complex of doxycycline was prepared in accordance with the first example of Patent of Sieger et In a 500 flask equipped with and thermometer was placed was immediately covered with 100 of To the mixture was added with stirring of distilled In a few a lower oily layer To this mixture was added 100 of methanol and on continued the oily layer peared in the methanol forming a complete An additional 50 of methanol was added to the flask and then of neutral was added intermittently with another 50 of A clear solution was maintained throughout the addition of the After addition of all of the the temperature in the reaction flask was One hour after addition of the the clear reaction solution was poured into 1S00 of A yellow product separated and was collected on a coarse sintered glass filter and dried at The cyline metaphosphoric acid complex weighed about Solubility in water at Melting point with at 274 at mu in methanol containing hydrochloric Specific rotation in methanol containing II concentrated hydrochloric Water content by Karl Fisher of the product above obtained was suspended in 4 of water and stirred with of The product did not dissolve but formed a gummy The cycline content of the supernatant after half an hour was The mass triturated with isopropanol crystallized to yield doxycycline base The latter assay was repeated but using 5 of A gummy product was again obtained and the content of the supernatant was of the metaphosphoric acid complex of cycline above obtained was suspended in 4 of water and of N was forming a gummy which consisted of doxycycline The doxycycline content o the supernatant was Comparative example was repeated with the sole difference that the clear reaction solution was precipitated by adding 750 of isopropyl alcohol instead of Melting point with 239 cm and 317 at in methanol containing concentrated hydrochloric Specific rotation in methanol containing concentrated hydrochloric Water content by Karl Fisher The infrared curve of the product was identical to that of comparative example with the exception that this latter showed traces of form by the accentuated maximum at about 13 grs of phosphorous pentoxide was covered with 100 of chloroform and of water was After stirring for two and a half 100 of methanol was added and stirring continued for an additional 15 an additional 50 of methanol was followed by the of 23 of cycline base and 50 of at a perature not exceeding and maintaining a clear tion throughout the After an hour of subsequent 400 of isopropanol was which provoked the precipitation of the metaphosphoric acid complex of cycline proportion of the reactants 5 moles of moles of It was then washed with isopropanol and dried at It weighed Solubility in water at Melting range with 249 at and 326 at mu in methanol containing concentrated hydrochloric Water content by Karl Fisher To of the above substance in 10 of 1 of normal sodium hydroxide was added with a view to preparing from this metaphosphoric acid complex the water soluble sodium complex of doxycycline the product did not which was formed crystallized overnight and its infrared sorption curve was identical to that of doxycycline base Comparative example C was repeated but adding grs of doxycycline base monohydrate instead of 23 The metaphosphoric acid complex of doxycycline thus obtained proportion of the reactants 4 moles of Solubility in water at Melting range 257 at and 336 at 268 mu in methanol 1 cm taining concentrated hydrochloric Specific rotation in methanol containing concentrated chloric Water content by Karl Fisher To of the above substance in 10 of 2 of normal sodium hydroxide was added with a view to preparing from this metaphosphoric acid complex the water soluble sodium complex of doxycycline the acid complex did not even after stirring for 24 The soluble material which crystallized overnight consisted mainly of doxycycline base For the purpose of further comparison and doxycycline base monohydrate was reacted with metaphosphoric acid in aqueous medium in various mole ratios as to obtain the respective acid addition salts according to Patent of doxycycline base hydrate were dissolved in 15 of dimcthylformamide and a solution of of metaphosphoric acid in 5 of water was After stirring for half an it was washed and It weighed and 328 at in methanol containing concentrated hydrochloric Its infrared absorption in mineral oil mull has the following main y It differs essentially from that of the metaphosphoric acid complexes of doxycycline as well as from that of the complexes of the present grs of doxycycline base monohydrate were dissolved in 15 of di ethylformamide and of acid dissolved in 30 of water was After stirring for half an it was washed and The product obtained and had a solubility in water at of 238 at mu and 319 at mu in methanol 1 cm containing hydrochloric Comparative example B above was repeated but adding 1 of normal sodium hydroxide after addition of the metaphosphoric acid The product obtained weighed and had a solubility in water at of 260 at mu and 340 at mu in methanol 1 cm taining concentrated hydrochloric The of a aqueous suspension was Its infrared absorption curve in mineral oil mull has the following main This absorption curve differs only slightly from that of doxycycline base it differs considerably from that of the polymetaphosphate sodium complex described in example and it also differs from that of the cxamplo was repeated but using of doxycycline base monohydrate instead of The product obtained 4 6 and had a solubility in water at of 238 at mu and 311 at in methanol contain concentrated hydrochloric Comparative example D above was repeated but adding 2 of normal sodium hydroxide after addition of the acid The product obtained weighed and had a solubility in water at of AT mu and 426 at mu i methanol containing concentrated hydrochloric It consisted mainly of doxycycline base To grs of doxycycline hyclate dissolved in 20 of a solution of of metaphosphori acid in 5 of water was added under After 30 was washed with water and The acid addition salt of doxycycline S weighed and had a solubility in water at of 245 at mu and 320 at mu 1 cm methanol containing 15 concentrated hydrochloric cific rotation in methanol containing II concentrated hydrochloric 750 rags of the compound obtained under F was suspended in 5 of water and ml of normal sodium hydroxide solution was It dissolved first but then yielding g of impure doxycycline base mon Solubility in water at cm 332 at in methanol containing 15 concentrated hydrochloric of a solution Comparative example F was repeated but using prepare the acid addition salt of 4 moles of doxycycline 6 moles of mctaphosphori c The yield was grs bility in water at 245 at mu 1 cm and 330 at mu in methanol containing concentrated hydrochloric Specific rotation in methanol containing concentrated hydrochloric Its infrared absorption curve was comparable to that of the product obtained in example 9 625 mgs of the product obtained above under G was suspended in 5 of water and ml of normal sodium hydroxide solution was added under The product first dissolved and then It consisted of pure doxycycline base Solubility in water at mu in methanol taining concentrated hydrochloric In an attempt to prepare a hexametaphosphate sodium complex from the simple acid addition salt of to an aqueous solution of of doxycycline g of acid dissolved in mis of water was and 6 mis of normal sodium hydroxide tion was subsequently added in one After stirring for half an it was washed with water and weighing Its infrared absorption curve was tially identical to that of the hexametaphosphate sodium plex of doxycycline described in example cm my in methanol containing concentrated hydrochloric With a view to comparing and the alkali metal polyphosphate complexes of doxycycline from the complexes obtained in accordance with the above cited prior With a view to for differentiation the double salt of metaphosphoric acid as cation with doxycycllne and both as the following experiments were of phosphorous was weighed in of chloroform as to avoid prolonged contact with the in a dry of water was added and the mixture was stirred The chloroform was eliminated by distillation in and the metaphosphoric thus was dissolved in 30 of water to which 10 of doxycycllne base suspended in 40 of wate was under After 1 it dissolved and to the clear of sodium dissolved in 5 of was under The clear solution obtained was frozen at once a mixture of acetone and dry and Melting point in methanol containing concentrated hydrochloric at 268 mu and 240 at methanol containing concentrated hydrochloric 100 of the product obtained above was dissolved in of water from which a not identical to the hexametaphosphate of doxycycllne or to the polyphosphate monosodium complex of slowly started to Experiment 11 A was repeated instead of freezing the it was stirred for 1 yielding a precipitate which was then washed with water and Melting point in methanol containing concentrated hydrochloric and 253 at 351 mu methanol containing concentrated hydrochloric The product obtained is not identical to the phosphate monosodium complex of nor to the hexametaphosphate of C Experiment 11 B was repeated the order of the reactants metaphosphorlc acid plus sodium then doxycycllne base in 11 and doxycycllne base monohydrate plus sodium sodium then metaphosphorlc in experiment 11 After standing the precipitates formed in both cases were identical to that of experiment 11 In order to demonstrate that the polyphosphate monosodium eomplex of doxyoycllne is bound by calcium phosphate in a lesser degree than the following experiment was carried To 20 of a molar aqueous solution of cycllne hyelate were added of sodium bicarbonate and 6 of the pH being After the solution was still clear and then to 29 of the above solution of calcium phosphate was added and the solution was stirred for 1 The pH at the end of this period was It was subsequently filtered and the doxycycllne content of the filtrate was determined by violet absorption at 350 the same experiment was carried out with a 20 aqueous solution of the polyphosphate monosodium complex of doxycycllne obtained in example having a concentration of initial pH was 2 and the final pH The results were as Doxycycllne content of filtrate Doxycycllne hyclate Doxycycllne polyphosphate monosodium complex 1202 the of the polyphosphate monosodium complex of doxycycllne by calcium phosphate is less than a quarter of tha of doxycycllne around neutral SERUM LEVELS AFTER ADMINISTRATION OF 2 C DOXYCYCLINE HYCLATE of volunteers 0 h 1 h 3 h 1 0 2 0 3 0 5 0 6 0 7 0 8 0 0 Average SERUM LEVELS AFTER OF 2 CAP OF DMSC of volunteers 0 h 1 h 3 7 1 0 2 0 3 0 5 0 6 0 7 0 8 0 9 0 Average Substance Composition mole proportion Solubi of the in wa at 20 Monosodium polymetaphosphate complex of doxycycline 330 polymetaphosphate complex of doxycycline 292 Metaphosphoric acid 1 mole HP03 complexes of doxycycline to process in 5 moles moles Patent 4 moles moles HPOj 3 moles moles Hexametaphosphate sodium complex of doxycycline to process in Patent Doxycycline hyclate and 330 Doxycycline base monohydrate and method according to Example 1 of Patent Addition of 1 mole aqueous NaOH yields doxycycline base monohydrate Addition of 2 moles aqueous NaOH yields doxycycline base monohydrat of 3 moles aqueous NaOH yields doxycycline base monohydrat Subs tance proportion of reactants Solvent S NaOH as base Doxycyline 6 6 0 metaphosphoric acid addition salt 5 6 0 to cess in Patent 4 6 0 0 2 3 6 0 5 6 1 4 6 2 as hyclate 5 6 0 H20 4 6 0 5 5 6 H20 Product is impure base monohydrate Addition of 1 mole NaOH yields the impure base monohydrate Addition of 1 mole NaOH yields the impure base monohydrate Product is hexametaphosphate sodium complex as in Example 7 insufficientOCRQuality

Claims (1)

1. WHAT IS CLAIMED A process for the preparation of complexes of of the formula Me z 1 to to y 1 to x y 6 and z having a solubility at superior to eomprislng reacting metaphosphorlc acid a reaction inert organic medium with 1 to 5 moles of then neutralizing the remaining free acid groups of metaphosphorlc acid with a or ethanolic solution of sodium or potassium hydroxide in a stoichiometrical and precipitating the complex thus formed by addition of a reaction inert A process according to claim wherein the reaction organic medium solvent is and reaction inert propyl ether or An solvate of a complex of hydroxytetracyeline and an alkali metal salt of metaphosphoric acid having at least one free acid said being present in 1 to 5 moles per mole of and said complex having a solubility of to about 300 The solvate of the complex according to claim 3 of the formula The solvate of the complex according to Claim 3 of the formula insufficientOCRQuality