FI86140B - Method for the production of a pharmaceutical preparation which contains a drug which is either difficultly soluble, or unstable, in water - Google Patents

Abstract

Novel pharmaceutical compositions comprise inclusion compounds of drugs, which are instable or only sparingly soluble in water, with partially etherified beta -cyclodextrin derivatives having hydroxyalkyl and optionally additional alkyl groups.

Description

1 86140

A process for preparing a pharmaceutical preparation containing a sparingly water-soluble or water-unstable drug

The invention relates to a process for the preparation of a pharmaceutical preparation containing a drug which is unstable or only sparingly soluble in water. This preparation is characterized by increased solubility in water and improved stability.

Many drugs are poorly or only sparingly soluble in water, so that suitable dosage forms such as drip solutions or injectable solutions are prepared using other polar additives such as propylene glycol, etc. If the drug molecule has basic or acidic groups, it is also possible to increase the solubility in water. This usually results in reduced efficiency or impaired chemical stability. Due to the altered distribution balance, the drug can penetrate the lipophilic membrane only slowly, corresponding to the concentration of the undissociated fraction, while rapid hydrolytic degradation can occur in the ionic fraction.

. . "Water-like" co-solvents such as low molecular weight; ; polyethylene glycols or 1,2-propylene glycol, are therefore used in the preparation of aqueous solutions of poorly water-soluble drugs which, however, cannot be considered pharmacologically inert, or the drug is dissolved using surfactants so as to encapsulate the drug molecules. Such dissolution has several disadvantages: The surfactant molecules used often have a strong hemolytic effect and the drug must be removed from the micelle by diffusion after administration. This results in a slowed down effect [compare B. W. Möller, Gelbe Reihe, Vol. X, pages 132ff (1983)].

2 86140 It can therefore be concluded that there is no satisfactory or generally accepted method of dissolution.

In the case of solid drugs, it is also important to make a poorly water-soluble drug soluble in water, because good solubility increases the effect of the drug in the body. It has been shown that ancillary compounds such as urea or polyvinylpyrrolidone complexes can improve the solubility of a compound, but these are not stable in aqueous solution. Such excipients are therefore at best only suitable for solid dosage forms of drugs.

The situation is different when using α-, β- and γ-cyclodextrins, which can also bind the drug to its ring in aqueous solution / W. Sänger Angewandte Chemie 92, 343 (1980) 7. However, the disadvantage is that β-cyclodextrin itself is only sparingly soluble in water (1.8 g / 100 ml), so that therapeutically necessary drug concentrations cannot be obtained.

If a cyclodextrin derivative is formed, its solubility and thus the amount of dissolved drug can be significantly increased. Accordingly, DE-A-31 18 218 discloses a dissolution method using methylated β-cyclodextrin as a monomethyl derivative having 7 methyl groups, and especially as a dimethyl derivative having 14 methyl groups. When using a 2,6-di-O-methyl derivative, for example, it is possible to increase the water solubility of indomethacin by 20.4-fold and the solubility of digitoxin by 81.6-fold. However, for therapeutic use, the methyl derivatives of β-cyclodextrin have considerable disadvantages. Due to their increased lipophilicity, they have a hemolytic effect and continue to cause mucosal and eye irritation. Their acute intravenous toxicity is greater than the already considerable toxicity of unsubstituted β-cyclodextrin. A further significant disadvantage of practical dosing is that the solubility of dimethyl-β-cyclodextrin and its 3,86140 complexes deteriorates sharply at higher temperatures so that crystalline dextrin precipitates on heating. This phenomenon makes it very difficult to sterilize these solutions at conventional temperatures of 100-121 ° C.

Surprisingly, it has been found that certain other β-cyclodextrin derivatives can form ancillary complexes which also significantly increase the water solubility of sparingly water-soluble and water-unstable drugs without the disadvantages described above.

The invention therefore relates to a process for the preparation of a pharmaceutical preparation by dissolving β-cyclodextrin ether in water and adding a sparingly soluble or water-unstable drug to form an accessory complex and optionally drying the resulting accessory complex solution, provided that the retinoid accessory are methyl, ethyl and 2-hydroxyethyl groups. The process according to the invention is characterized in that the β-cyclodextrin ether used is a partially etherified β-cyclodextrin whose ether substituents are hydroxyethyl, hydroxypropyl or dihydroxypropyl groups. . the water solubility of the ether is greater than 1.8 g per 100 ml of water. The partially etherified β-cyclodextrin can be represented by the formula (B-CD-> OR (I)): wherein the residues R are hydroxyethyl, hydroxypropyl or dihydroxypropyl groups and some of the residues R can: optionally be methyl or ethyl groups, wherein β-cyclo - the water solubility of the dextrin ether is greater than 1,8 g per 100 ml of water.

* 86140

The use of partially methylated β-cyclodextrin ethers having 7-14 methyl groups in the β-cyclodextrin molecule and known from DE-A-31 18 218 does not fall within the scope of the invention.

β-Cyclodextrin is a compound with 7 anhydro-glucose units in the ring structure. It is also called cyclohepta-amylose. Each of the 7 glucose rings contains three hydroxy groups in the 2-, 3- and 6-positions, which may be etherified. In the partially etherified β-cyclodextrin derivatives used according to the invention, only a part of these hydroxy groups is etherified with said hydroxyalkyl groups and optionally further with said alkyl groups. When carrying out etherification using hydroxyalkyl groups, which can be carried out by reaction with the corresponding alkylene oxides, the degree of substitution must be considered as a molar substitution (MS), i.e. moles of alkylene oxide per anhydroglucose unit, cf. U.S. Pat. No. 3,459,731, column 4 used in accordance with the invention has a molar substitution of between 0.05 and 10, preferably between 0.2 and 2. A highly preferred molar substitution is about 0.25-1.

Etherification with alkyl groups can be expressed directly as the degree of substitution (DS) per unit of glucose, which value as above is 3 with more complete substitution. Partially etherified β-cyclodextrins are used according to the invention, which contain, in addition to said hydroxyalkyl groups, also methyl or ethyl groups, up to a degree of substitution of 0.05-2.0, preferably 0.2-1.5. The most preferred degree of substitution of alkyl groups is between about 0.5-1.2.

The molar ratio of drug to β-cyclodextrin ether is preferably about 1: 6-4: 1, especially about 1: 2-1: 1. It is usually advantageous. the list uses a molar excess of complexing agent.

Useful complexing agents include hydroxyethyl, hydroxypropyl and dihydroxypropyl ethers, the corresponding ether mixtures of these, and further ether mixtures having methyl and ethyl groups such as methylhydroxyethyl, methylhydroxypropyl, ethylhydroxyethyl and ethylhydroxyethyl and ethyl. derived from β-cyclodextrin.

The preparation of hydroxyethyl ethers of β-cyclodextrin can be carried out using the method described in U.S. Patent 3,459,731, suitable methods for the preparation of β-cyclodextrin ethers are also disclosed in J. Szejtli et al. Stärke 32, 165 (1980) and AP Croft and RA Bartsch, T 1417 (1983). Ether mixtures of β-cyclodextrin can be prepared by reacting β-cyclodextrin in a basic, liquid reaction medium containing an alkali metal hydroxide, water and optionally at least one organic solvent (e.g. dimethoxyethane or isopropanol) with at least two different hydroxyalkylating and optionally alkylating and ethylene oxide, propylene oxide, methyl or ethyl chloride).

Drugs which have significantly improved water solubility and stability after conversion to the auxiliary β-cyclodextrin ethers mentioned above are those which have the required shape and size, i. which fit within the β-cyclodextrin ring system. These include, for example, non-steroidal anti-rheumatic drugs, steroids, cardiac glycosides and benzodiazepine, benzimidazole, piperidine, piperazine, imidazole or triazole derivatives.

Useful benzimidazole derivatives include thiabendazole, fuberidazole, oxybendazole, parbendazole, cambendazole, mebendazole, fenbendazole, flubendazole, albendazole, oxyfendazole, nocodazole and astemizole. Suitable piperidine derivatives include fluspirilene, pimozide, penfluoridol, loperamide, astemizole, ketanserin, levocabastine, kisapride, altanserin and ritanserin. Suitable piperazine derivatives * - ** · include, for example, lidoflazine, flunarizine, mianserin, oxatomome, myoflazine and kinnaricin. Examples of suitable imidazole derivatives are metronidazole, ornidazole, ipronidazole, tinidazole, isoconazole, nimorazole, burimamide, methamide, methomidate, enilconazole, etomidate, econazole, clotrimazole, carnidazole, carnidazole, carnidazole, carnidazole, orconazole, butoconazole, triadiminol, thioconazole, valconazole, fluotrimazole, ketoconazole, oxiconazole, lombazole, bifonazole, oxymethidine, fenticonazole and tubulazole. Suitable triazole derivatives include virazole, itraconazole and terconazole.

Highly valuable pharmaceutical compositions are obtained by converting etomidate, ketoconazole, tubulazole, itraconazole, levocabastine and flunarizine into a water-soluble form using the complexing agents described above.

In the process according to the invention, the β-cyclodextrin ether is dissolved in water and the selected drug is added thereto, and the solution of the adjuvants formed is optionally dried using methods known per se. The formation of the solution can take place at a temperature between 15 and 35 ° C.

The drug is suitably added in portions. The water may also contain physiologically acceptable compounds such as sodium chloride, potassium nitrate, glucose, mannitol, sorbitol, xylitol or buffering agents such as phosphate, acetate or citrate. buffer.

When β-cyclodextrin ethers are used according to the invention, it is possible to prepare dosage forms of medicaments for oral, parenteral or superficial use, e.g. infusion and injection solutions, drip solutions (e.g. eye or nasal drops), sprays, aerosols, syrups and medicated baths.

Aqueous solutions may still contain suitable physiologically compatible preservatives, such as quaternary ammonium soaps or chlorobutanol.

7 86140

To prepare solid products, solutions of the ancillary compounds are dried using conventional methods. In this case, the water can be evaporated, for example in a rotary evaporator or by lyophilization. The residue is ground and optionally modified, after addition of some other inert ingredients, into uncoated or coated tablets, suppositories, capsules, ointments or salves.

The following examples illustrate the invention, but the invention is not limited to these examples.

The phosphate buffer solution mentioned in the examples had a pH of 6.6 and had the following composition: KH 2 PO 4 68.05 g

NaOH 7.12 g water ad 5000.0 g

All percentages are by weight.

Example 1 Starting from a 7% mother liquor solution of hydroxyethyl-β-cyclodextrin (MS 0.43) in phosphate buffer solution, a dilution series was prepared by gradually increasing the concentration of the complexing agent by 1%. 3 ml of these solutions were pipetted into 5 ml • v '· test tubes containing the test drug. After shaking for 24 hours at 25 ° C, the solution was filtered through a membrane filter (0.22 microns) to dissolve the dissolved drug. the amount was determined using a spectrophotometer. Figures 1, 3 and 4 show the increase in drug concentration in solution relative to comp. . to the concentration of the lex-forming agent using indomethacin (Figure 1), piroxicam (Figure 3) and diazepam (Figure 4).

‘The maximum concentration of the drug is limited by the cyclodextrin derivative: **. · Its saturation solubility in the buffer obtained in the case of hydroxy- * * ethyl-g-cyclodextrin (MS 0.43) at 7.2 g / 100 ml.

8 86140

For example, comparing the results obtained with indomethacin with those obtained according to DE-A-31 18 218 with 2,6-di-O-methyl-6-cyclodextrin (Figure 2), it can be seen that the hydroxyethyl derivative has a considerable higher complexation constant (compare different curve slopes in Figures 1 and 2).

Example 2 A. The saturation solubility of various drugs at 25 ° C was determined using a 10% hydroxypropyl-β-cyclodextrin solution (MS 0.35) in phosphate buffer solution under the same conditions as in Example 1. Saturation solubilities in phosphate buffer solution and S2 in phosphate buffer solution and 10% phosphate buffer solution: in β-cyclodextrin, is shown in Table 1.

Table 1 Drugs (mg / ml) S £ (mg / ml) Ratio S 2: S 2

Indomethacin 0.19 5.72 1: 30.1

Digitoxin 0.002 1.685 1: 842.5

Progesterone 0.0071 7.69 1: 1083.0

Dexamethasone 0.083 14.28 1: 172.0

Hydrocortisone 0.36 21.58 1: 59.9

Diazepam 0.032 0.94 1: 29.4 ... B. Solubility of drugs in 4% hydroxypropyl methyl; ** in 4% aqueous solution of g-cyclodextrin (DS 0.96; MS 0.43) was determined in the same manner. The results obtained are shown in the following Table 2, in which the ratio of the saturation solubility R in water or at a given pH, respectively, with the addition of: β-cyclodextrin derivatives and without it, is shown for each drug. The solutions prepared according to the invention. were also found to be significantly more stable compared to aqueous solutions.

• · · »· 9 86140

Table 2

Drug R

Intraconazole pH 5 96 pH 2.5 75

Flunarizine 18

Levocabastine pH 9.5 81 pH 7.4 8

Ketoconazole 85

Flubendazole 30

Tubulazole 43

Kisapridi 3

Loperamides 62

Etomidate 8.5

Kinnaricin pH 5 28 pH 3 12

Example 3 0.7 g of hydroxyethyl 3-cyclodextrin (MS 0.43) was dissolved in 10 ml of phosphate buffer solution together with 0.04 g of indomethacin at 25 ° C until a clear solution formed. This solution was filtered through a well filter (0.22 microns) and filled using laminar flow into a pre-sterilized vial stored at temperature. :: 21 ° C (B). In a parallel experiment, a saturated solution of indazine in phosphate buffer solution (0.21 mg / ml) was stored under the same conditions (A). The drug concentrations determined by high pressure liquid chromatography are shown in Table 3.

: The considerably improved stability of the mixture according to the invention is obvious.

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Table 3

Storage time Indomethacin content (%) weeks A b 0 100.1 99.7 2 91.2 99.9 4 79.1 98.1 6 69.8 98.6 8 64.8 98.4

Example 4 (Injectable preparation) 0.35 g of hydroxypropyl-S-cyclodextrin (MS 0.35) was dissolved in 5 ml of physiological sodium chloride solution and heated to about 35 ° C, after which 3 mg of diazamam was added. After short-term storage, a clear solution was obtained which was filled into an ampoule after filtration through a membrane filter (0.45 microns).

Example 5 (Tablet) 7 g of hydroxyethyl 8-cyclodextrin (MS 0.43) and 0.5 g of medroxyprogesterone acetate were dissolved in 100 ml of water. The water was then evaporated on a rotary evaporator. The residue (75 mg) was finely ground, and after the addition of 366 mg of calcium hydrogen phosphate.2, 60 mg of corn starch, 120 mg of cellulose powder (microcrystals), 4.2 mg of highly dispersed silica (*: *: dioxide ( AEROSIL® 200) and 4.8 mg of magnesium stearate, prepared; tablets weighing 630.0 mg and containing 5 mg of drug per tablet were administered. Methoxyprogesterone acetate:. the dissolution rate of this preparation is 21 times higher compared to a tablet containing the same inert ingredients but without the addition of O-cyclodextrin ether.

- "Example 6 V: 5 g of hydroxyethyl-O-cyclodextrin (MS 0.43) and 14 mg of *: vitamin A acetate were dissolved with stirring in 100 ml of water or sugar solution (5% aqueous solution). ) After filtration through a membrane filter, 11,861,140 (0.45 microns) were filled into ampoules and sterilized or filled into dropping flasks to which 0.4% chlorobutanol was also added as a preservative.

Example 7 5 g or 7.5 g of hydroxyethyl-g-cyclodextrin (MS 0.43) and 0.5 g or 0.75 g of lidocaine were dissolved in 100 ml of physiological sodium chloride solution at 30 ° C (B). Injectable solutions, eye drops and solutions for superficial use were prepared as described in Example 6. Comparing the anesthetic effect of these solutions in experimental animals with aqueous lidocaine HCl solution (A), a 300% increase in the duration of action can be observed. Experimental procedure: Rats were injected with 0.1 ml of this solution at the base of the tail near the right or left nerve pathway and the stimulation was performed electrically. The results are shown in Table 4.

Table 4 Drug concentration Duration of action (min) Elongation _ {%) _ A_B_ (%) 0.5 56 163 291 0.75 118 390 330 ;; Example 8 6 mg of dexamethasone and 100 mg of hydroxyethyl-β-cyclodextrin (MS 0.43) were dissolved in 5 ml of water, sterilized by filtration through a membrane filter (0.22 microns) and packaged in aerosol bottles containing 0.1 ml per dose.

Example 9: The acute intravenous toxicity of a few β-cyclodextrins was tested in rats with the following results. In this case, it was surprisingly found that the toxicity of the derivatives used according to the invention in women is considerably lower.

* · «• · i2 86 1 40

Table 5 LDj-q in rats (iv), mg / kg body weight β-cyclodextrin 453 dimethyl-β-cyclodextrin 200-207 (DS 2.0) hydroxypropylmethyl-β-cyclodextrin> 20001 (DS 0.96; MS 0, 43) * Higher doses were not tested. In mice, this value was> 4000 mg / kg.

The hemolytic effect of the methyl ether according to DE-A-31 18 218 was compared with the corresponding effect of the ether used according to the invention. For this purpose, 100 [mu] l of physiological sodium chloride solution containing 10% cyclodextrin, 800 [mu] l of buffer (400 mg MOPS; 36 mg Na2HPO2. 2H, 0.6 g NaCl in 200 ml) and 100 [mu] l human erythrocyte suspension (washed three times with brine) was stirred for 30 minutes at 37 ° C. The mixture was then centrifuged and the optical density determined at 540 nm.

Reference solutions: a) 100 ul of sodium chloride solution + buffer -> 0% haemolysis b) 900 ul of water -> 100% haemolysis.

• 1 The results obtained are shown in Table 6 below, which shows: V the concentrations at which 50% and 100% hemolysis occurred.

• 1 »· •» ► * 1 m m »1 i3 861 40

Table 6

Compound C50% C100 *

Dimethyl- (3-CD (DS 2.0) 0.33% 0.5%

Methyl g-CD (DS 1.79) 0.53% 0.8%

Hydroxypropylmethyl-β-CD

(DS 0.96; MS 0.43%) 1.5% 4%

The results show that the hemolytic effect of hydroxypropyl methyl ether is about 5-8 times weaker than that of the previously used dimethyl ether. Animal experiments have also shown that hydroxyalkyl ethers do not cause mucosal and ocular irritation unlike methyl ethers.

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Claims (13)

A process for the preparation of a pharmaceutical preparation by dissolving a β-cyclodextrineter in water and adding a drug which is poorly soluble in water or is unstable in water to form an inclusion complex and possibly dry the obtained solution of the inclusion complex, provided that the inclusion complexes of retinoids with β-cyclodextrin ethers are excluded, where their ether substituents are methyl, ethyl and 2-hydroxyethyl groups, characterized in that, as β-cyclodextrinets, a partially etherified β-cyclodextrin whose ether substituents are hydroxypropyl or dihydroxypropyl groups, some of the ether substituents possibly being methyl or ethyl groups and the β-cyclodextrin ether having a water solubility greater than 1.8 g in 100 ml water. Process according to Claim 1, characterized in that a preparation containing a partially etherified β-cyclodextrin is prepared, wherein the molar substitution degree of the hydroxyalkyl substituents is 0.05-10 and the degree of substitution of the alkyl substituents is 0.05-2.0. Process according to Claim 1 or 2, characterized in that a preparation containing the drug and the β-cyclodextrineter is produced in the molar ratio 1: 6-4: 1. ; ; Method according to any one of claims 1-3, characterized in that a preparation is prepared which, as a medicament, contains a non-steroidal anti-rheumatic agent, a steroid, a cardiac glycoside or derivatives of benzodiazepine, benzimidazole, piperidine, piperazine, imidazole or triazole. Process according to any of claims 1-4, characterized in that a preparation is prepared which, as a medicament, contains etomidate. • ♦ i7 861 40 Process according to any one of claims 1-4, characterized in that a preparation is prepared which, as a medicament, contains ketoconazole. Process according to any of claims 1-4, characterized in that a preparation is prepared which, as a medicament, contains itraconazole. Method according to any of claims 1-4, characterized in that a preparation is prepared which, as a medicament, contains levocabastine. Method according to any of claims 1-4, characterized in that a preparation is prepared which, as a medicament, contains flunarizine. Process according to any of claims 1-4, characterized in that a preparation is prepared which, as a medicament, contains tubulazole. 11. A process according to any one of claims 1-10, characterized in that the ether obtained after removal of the solvent is pulverized and possibly after addition of additional auxiliaries, is transferred in a solid dosage form. Method according to any one of claims 1-11, characterized in that additional physiologically suitable agents are added in the water. Process according to claim 12, characterized in that sodium chloride, glucose, mannitol, sorbitol, xylitol or a phosphate or citrate buffer are added in the water.