NO150183B - PROCEDURE FOR MANUFACTURING INJECTION SOLUTIONS - Google Patents

Description

The present application relates to a method for the production of water-based injection solutions containing a lipoid which is a phosphatide or a sphingolipid, a benzodiazepine, preferably diazepam, isotonizing additives

nings and/or■pharmaceutical auxiliaries by mixing the components. In the past, such pharmaceuticals were brought into solution with the help of synthetic solubilizers such as e.g. propylene glycol, polyethylene glycols, "Cremophor EL", "Tween" and "Pluronics". The solubilization of certain of these substances such as Cremophor EL, Tween and "Pluronics"

is based on the formation of a colloidal system (micelles).

However, these synthetic solubilizers, including micelle formers such as Cremophor EL, Tween and "Pluronics", show different side effects when applied parenterally, such as e.g. allergic reactions, anaphylactic shock, haemolysis and pyrogenic effects.

On the other hand, it is known that there are also natural micelle formers, e.g. bile acid derivatives. These natural micelle formers are ionogenic and therefore highly lytic. They cause hemolysis and have thus far not been used as vehicles for parenteral application.

In patent claim 1 in Austrian patent no. 225,851, a method is described for the production of aqueous choline phosphoric acid diglycerol ester solutions which are suitable for injection

goal, which is characterized by reacting cholamin phosphoric acid diglycerol ester-free, natural choline phosphoric acid diglycerol esters with a high content of unsaturated and essential fatty acids with an aqueous solution of a bile acid salt in an alkaline medium, in which less than 1

mole of bile acid sold per moles of ester. Claim 4 in this patent relates to a design of the method according to claim 1, which is characterized by first mixing a highly diluted alcoholic solution of the diglycerol ester with ct-tocopherol, removing the alcohol in the presence of an inert base under reduced pressure and reacting it thus obtained product with an aqueous solution of a bile acid salt. Lines 3-5 on page 3 of this patent state: "Surprisingly, it has been shown that the adduct also gives a water-soluble compound when reacted with the bile acid salt, despite the fact that a-tocopherol itself is known not to be water-soluble."

According to what is known today, a mixed micelle forms between the bile acid derivative and the lipoid which is capable of solubilizing the inherently water-insoluble α-tocopherol. Within the scope of the present invention, it has now surprisingly been found that in this carrier one can not only solubilize amphiphilic molecules of the α-tocopherol type, but also larger, spherical, non-amphiphilic molecules of the benzo-diazepine type. From German specification 24 33 173, aqueous injection solutions of lipids are known, which contain cholanic acid derivatives and ethanol for the solubilization of inherently water-insoluble lipids.

From Acta Pharmacol. a toxicol. 1975, 36, 312-320 is one

aqueous diazepam emulsion known for injection purposes. In contrast to the new clear transparent micellar solutions produced according to the present invention, this preparation is an opaque, milky emulsion which must be protected from cold to prevent a complete phase separation.

It was now surprisingly found that the aforementioned disadvantages of micelle formers, in particular the hemolytic effect of natural micelle formers, can be substantially reduced if not completely avoided by the addition of lipoids.

The present invention thus relates to a method

of the type mentioned at the outset which is characterized by the fact that the components are further added to a micelle former which is a bile acid derivative with the general formula I

where R-^, R2 and R-, means hydrogen, hydroxy or an exocyclic keto group and R^ a carboxy group which is linked to the amino group of an amino acid by an amide bond, derivatives thereof which in the steroid skeleton contain one or two double bonds or salts of such compounds in such an amount that the ratio between the lipid and the bile acid derivative is 0.1:1 to 2:1. As micelle formers, bile acid derivatives of the general formula I are mentioned,

where R 1 , R 2 . and R^ means hydrogen, hydroxy or an exo-cyclic keto group and R^ a carboxy group which can be linked to the amino group of an amino acid by an amide bond, as well as derivatives thereof which contain one or two double bonds in the steroid skeleton and salts of such compounds.

Particularly preferred are those substances of formula I where R 1 , R 2 and R 2 mean hydroxy. These are the tri-hydroxy-bile acids. Of these, the following compounds are preferred: Furthermore, substances with 2-hydroxy groups are preferred, that is to say the dihydroxybile acids. Of these, the following compounds are again preferred:

Derivatives of the compounds of formula are also suitable

In which contains one or two double bonds in the steroid skeleton such as e.g. in position 7-8, 11-12 or 9-11.

As salts of these bile acid derivatives, alkali salts in particular come into consideration, particularly preferably sodium salts.

As lipoids, the following compounds come into consideration:

Particularly preferred are phosphatides, especially phosphatidylcholine.

Also with the new injection solutions produced according to the present invention, as with the usual injection solutions, isotonizing additives are necessary. As isotonizing additives, the following come into particular consideration: physiological saline and glucose solution, tris buffer, phosphate buffer, citrate buffer, glycine buffer, citrate-phosphate mixed buffer, etc.

The osmotic pressure of the injection solutions according to the invention should approximately correspond to blood, i.e. approx. 300 mOsm, but can vary within certain limits.

Benzodiazepines can be diazepam, clorazepam, flunitrazepam, nitrazepam, medazepam and bromazepam.

The relationship between the lipoid component and the micelle former

is in the order of magnitude from 0.1:1 to 2:1. Mixing ratios from 0.1:1 to 0.8:1 and 1.5:1 are preferred. to 2:1. Particularly preferred is the mixing ratio of 0.8:1 to 1.5:1.

The proportion of lipoid component plus micelle former in the injection solutions can vary within wide limits and e.g. be 50-300 mg per ml injection solution.

The proportion of benzodiazepine in the injection solution can be

are led to vary within wide limits and e.g. be 0.1 - 20

mg per ml injection solution.

The injection solution prepared according to the invention can be prepared by simple mixing of the individual components. However, it is an advantage to dissolve the lipoid component, the micelle former and the water-heavy or insoluble active ingredient(s) in an organic solvent, evaporate and then add water, add the isotonizing additives and possibly the further ingredients, usually including the isotonizing additives and for the most part, any further ingredients are also mixed with the water before the addition of said evaporation residue. As an organic solvent, such come into consideration in which the component is to be dissolved

is sufficiently soluble, such as e.g. lower alkanols,

especially ethanol.

A particularly preferred method thus consists in vigorously stirring one molar part of the micelle former, approximately one molar part of the lipoid component and approximately 50 - 250 molar parts of water, possibly in the presence of up to 2% of an organic solvent such as ethanol as well as those in water heavily or insoluble active substance(s) until the mixture appears homogeneous, after which the water, isotonizing additives and possibly the further ingredients are added until the desired dilution or concentration is reached. However, it is also possible to carry out the above procedure without active substance and only finally solubilize the active substance or active substances in the micellar solution.

The time required for the above-mentioned mixture to appear homogeneous after stirring depends on the type of micelle former, the lipoid component and the active substance and can usually be shortened by brief heating.

Since, on the one hand, lipoids and active substances can react very easily with oxygen, it is advantageous or appropriate to work under oxygen-free conditions and especially in a nitrogen atmosphere. Preferably, an antioxidant such as e.g. sodium ascorbate, sodium hydrogen sulphite or sodium pyrosulphite.

In addition to the previously mentioned advantages, the new injection solutions show the further advantage that they are well miscible with plasma as with normal infusion solutions, e.g. isotonic glucose or saline solution.

As a further advantage, it has been shown that the active ingredient or active ingredients are released extremely easily from the injection solution.

Likewise, it is an important fact that the new injection solutions produced according to the invention are very

slightly toxic.

The following examples illustrate the invention.

EXAMPLE 1

a) 3 g Egg lecithin (isolated according to Singleton et al. J. Am. Oil. Chem, Soc. 4_2 (1965) 53), 2 g sodium glycocholate and 150

mg of diazepam is dissolved in a round flask in 150 ml of ethanol treated with nitrogen. b) The ethanol is evaporated under vacuum at 35°C in a rotary evaporator. A lipid film forms in the round bottom flask. c) Under nitrogen, add 25 ml of a 1/15 M phosphate buffer solution (pH 7) treated with nitrogen. The micelles form

spontaneously at room temperature.

d) 300 mg sodium ascorbate powder is added and dissolved.

e) Sterilized under laminar flow conditions

the solution and filled into nitrogen-containing ampoules. These

merged. During the entire procedure, contact with air is avoided in order to obtain an oxygen-free solution in the ampoule.

EXAMPLE 2

a) 2.9 g egg lecithin, 2 g sodium taurocholate and 150 mg diazepam are dissolved in a round flask in 150 ml treated ethanol

with nitrogen.

b) to e) are carried out as in example 1.

EXAMPLE 3

a) 40 mg sodium glycocholate is dissolved in 1 ml 1/15 M phosphate buffer. b) Add 61.6 mg of egg lecithin and stir until the solution becomes clear (approximately 2 days).

c) 10 mg of diazepam is introduced.

d) After 12 hours, the solution settles. The supernatant

contains the mixed micelles 2 mg per ml diazepam.

EXAMPLE 4

Proceed as in example 3, but use 62.2 mg of phosphatidylinositol instead of egg lecithin.

EXAMPLE 5

Proceed as in example 3, but use 65.4 mg of phosphatidylserine instead of egg lecithin.

EXAMPLE 6

Proceed as in example 3, but instead of egg lecithin 6 use 0.6 mg of sphingomyelin.Sphingolipids (see Biokemi 1, Kbh 1971).

EXAMPLE 7

Proceed as in example 3, but instead of egg lecithin use 61.6 g of sulfatide (bovine). Sphingolipids (see Biokemi 1, Kbh 1971).

EXAMPLE 8

Proceed as in example 3, but use 57.2 mg of dimyristoyl lecithin instead of egg lecithin.

EXAMPLE 9

The procedure is as in example 3, but instead of 61.6 mg of egg lecithin and 40 mg of sodium glycocholate, 11.8 mg of c-ardiolipin (diphosphatidylglycerol) and 20 mg of sodium glycolate are used.

EXAMPLE 10

75 mg of egg lecithin and 48.7 mg of sodium glycochlate are dissolved in 1/2 ml of methanol.

b) The methanol is evaporated on a rotary evaporator at 35°C

under vacuum.

c) 1 ml of 1/15 M phosphate buffer is added.

d) Stir in 5 mg of diazepam.

e) After 12 hours of stirring at room temperature, settle

the solution. The supernatant contains the mixed micelles

2.2 mg per ml diazepam.

EXAMPLE 11

a) To 5.58 g of glycc cholic acid add 1.2 ml of a 10 M NaOH solution and 24.4 ml (with ^-treated, C^-free, K-free) 1/15

M phosphate buffer in a .100 ml round flask, after which one for

hand shakes until complete dissolution.

b) 9.6 g of soy lecithin, 200 mg of diazepam and 600 mg of sodium ascorbate are added, shaken and stirred to a homogeneous, viscous,

honey-like phase occurs.

c) A further 20 ml of 0?-free phosphate buffer is added. A yellowish clear solution is formed which is sterilized.

Claims (2)

1. Method for the production of water-based injection solutions containing a lipoid which is a phosphatide or a sphingolipid, a benzodiazepine, preferably diazepam, isotonizing additives and/or pharmaceutical excipients by mixing the components, characterized in that the components are further added to a micelle former which is a bile acid derivative with the general formula IN where R^, R2 and R3 mean hydrogen, hydroxy or an exo-cyclic keto group and R^ a carboxy group which is linked to the amino group of an amino acid by an amide bond, derivatives thereof which in the steroid skeleton contain one or two double bonds or salts of such compounds in such an amount that the ratio between the lipid and the bile acid derivative is 0.1:1 to 2:1. 2. Method according to claim 1, characterized in that the proportion of lipoid component plus micelle former is 50-300 mg/ml.