DK154605B - METHOD OF MANUFACTURING SYNTHETIC BLOOD - Google Patents

Description

DK 154605 B

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The need for synthetic blood is well known. Blood becomes more expensive and more expensive, it is perishable, it must fit the recipient's blood type, and the transfusion itself can cause hepatitis if strict procedures are not observed.

5 In addition, blood donations appear to be somewhat seasonal, and they often do not coincide with the usually random need for blood.

A synthetic blood must have several different properties. First of all, and quite obviously, it must have a high oxygen and carbon dioxide solubility, since its essential function is to transport oxygen and carbon dioxide. A synthetic blood must also be non-toxic, and in this context it is desirable that no residual of the synthetic blood be left in vital organs when replaced with natural blood.

Another necessary feature of blood substitutes is that they must meet certain vapor pressure requirements. The blood substitutes leave the body through exhalation and evaporation through the skin. Preferably, the blood substitute leaves the body 20 at about the same rate as that at which new, natural blood is formed by the body. If the substitute vapor pressure is too low, it stays in the body for too long, while, if it is too high, it evaporates throughout the body surface and causes problems related to diving.

25 Blood substitutes should also be able to form extremely stable emulsions, since this ability is even more significant in perfusion materials. Blood substitutes are usually immiscible with blood and, if used alone, can cause embolism. This problem is solved by using the blood substitute 30 in aqueous emulsion and it is clear that the emulsion must not be broken during use or storage. In the case of percussion materials, this requirement is even more stringent, since the oxygenators used to add oxygen to the perfusion material create very high shear stresses 35 and will break all emulsions except the most stable ones. Another reason why aqueous emulsions are used,

DK 154605 B

2 is that salts are added to the water to maintain the salt balance of the body.

The Green Cross Corporation, Osaka, Japan, has published a document dated September 11, 1974, regarding emulsions 5 of perfluorinated compounds as oxygen and carbon dioxide carriers. Some of the compounds described in the present invention are also mentioned by Clark et al. in Microvascular Research, Volume 8/3 1974, also presented at the Oxygen Transport to Tissue Symposium, Atlantic City, 10 N.J., April 11, 1974. The blood substitute and perfusion material chosen so far has been perfluorodecaline. It has several desirable properties, but the compounds described in the present invention appear to be superior to perfluorodecaline in several respects.

The present invention relates to a process for preparing synthetic blood, whereby a non-aromatizable perfluorinated compound is emulsified with water and a non-aromatizable emulsifier such that the amount of water in the final emulsion is greater than 40% by volume, 20 is characterized in that, as perfluorinated compound, lower alkyl-adamantane is used, except for dimethyladamantane, preferably 1-methyl-adamantane, the amount of which in the emulsion is 10-30% by volume and having a particle size of approx. 0.001-10 µιη, preferably 50% by weight of the particles having a size of 0.05-0.3 µm and the emulsion preparation 3 additionally, if desired, imparting a content of 10-100 cm 2 of oxygen (25 ° C, 3,760 mm Hg) per 100 cm of the perfluorinated compound.

The perfluorinated lower alkyladamantanes used in the process of the invention have an extremely high oxygen solubility, leave a very small residue in the body, form extremely stable emulsions, and have a very satisfactory vapor pressure for the present application.

The lower alkyladamantanes are e.g. methyladamantane, ethyladamantane, ethylmethyladamantane, ethyldimethyladamantane and triethyladamantane.

DK 154605 B

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The lower alkyladamantanes are used as mentioned in perfluorinated form. The term perfluorinated here encompasses compounds of which at least 95% by weight is completely fluorinated (i.e., perfluorinated in the strict sense), preferably at least 98% and especially 100%. In all cases less than 100%, the remaining amount will naturally be highly fluorinated.

Fluorination is carried out by known methods. The alkyl mantan may e.g. is slowly passed over a layer of CoF3 containing 2-3 times the stoichiometric amount of fluorine, 10 at 250-275 ° C, giving a partial fluorination. The procedure is then repeated at 300-350 ° C to give a complete fluorination of the whole except for a few percent impurities which are both saturated, partially fluorinated compounds and olefinic carbon fluorides. The former 15 compounds boil at least 10 ° C higher than the desired perfluoro compound and are removed by distillation. The latter compounds boil at practically the same temperature, and are therefore extracted with an amine such as diethylamine (DEA). Remaining amine is removed with concentrated sulfuric acid.

Residual acid is removed with 1% sodium hydrogen carbonate solution, which is then extracted with acetone. Finally, residual acetone is distilled off.

Usually, the emulsion composition contains 1-5% by volume of an emulsifier. The selection of an emulsifier is not critical, but the emulsifier should be non-toxic and form a stable emulsion. The preferred emulsifier is egg yolk phospholide, as it is well known that this is harmless to the body.

Also suitable for perfusion purposes are polyoxyethylenes and polyoxypropylenes which are commercially available as "Pluronics".

30 "Pluronic® F-68" has a molecular weight of 8,350 and forms a highly stable emulsion.

The emulsion can be prepared by conventional emulsifiers which produce high shear stresses such as a Manton-Gaulin homogenizer. The particle size of the emulsion is, as mentioned, 0.001-10 µm, often 0.01-10 µm and usually 0.05-0.5 µm, and preferably has 50% by weight.

DK 154605 B

4 of the particles have diameters of 0.05-0.3 μιη. As is well known, the particle size can be adjusted by the shear stress applied. The actual particle size of the emulsion is not as critical as its stability, which is further discussed hereinafter.

As stated above, retention of the material in the body is important. In the following, perfluorinated (PF) methyladamantane (MA) is compared with PF tributylamine (TBA), decalin (D) and methyldecaline (MD). These compounds are the top 10 blood substitutes and perfusion materials to date. Emulsions containing 10% of the material to be investigated, surfactant and water, are prepared and tested in the manner described in Science, Vol. 181, August, 1973, page 681. The various emulsions are injected into mice. The mice are killed at different intervals thereafter, the liver is analyzed and the percentage ratio between the original amount of injected PF material and the amount still in the liver is determined. The results obtained are listed below.

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Percentage of dose in the liver after the indicated number of weeks

Compound 2 6 12 20 25 PFD 2 2 2 2 PFMD 30 19 2 2 PFTBA 38 30 30 30 PFMA 7 1 30 It appears that PFMA (containing a small amount of a higher boiling impurity which delays its release from the body) is as good or better than PFD.

The relative stability of a PFMA emulsion is excellent, being stable for an unspecified period of time (e.g. over 6 months) at 4-7 ° C, while the PFD emulsion breaks during a few days at room temperature. and over a few weeks at 4-7 ° C. PFTBA is also excellent. See, e.g.

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Journal of Microvascular Research, August, 1974. Out of ever erulsion stability, an emulsion produced by PFMA has an optical density of 0.65, which means that the particle size of the material is much smaller and therefore 5 is much easier to emulsify. , than the PFTBA, which gives a value of 2.2.

It has also been found that the perfluorinated compounds of this invention have a very low toxicity. LD 50 of the compounds of this invention after infusion in Comparison 10 with other compounds are as follows: LD 50 (mg / kg)

Emulsion 1 hour 3 days 7 days 10.9% PFD 190 160 159 15 5% PFMA> 200> 200> 200 10% PFTBA> 200. 120 120

As noted above, the perfluorinated compounds of this invention have a high oxygen and carbon dioxide solubility.

For example, the perfluorinated compounds can usually contain about 3 40-60 cm oxygen per 100 m of carbon fluoride and the carbon dioxide solubility is about twice that. Normal blood 3 3 will absorb approx. 20 cm oxygen per 100 cm blood and has a carbon dioxide solubility that is twice the oxygen solubility. The compositions of the invention will normally contain 30 to 60 cm 100 cm of the perfluorinated material, but as mentioned, ratios as low 3 3 3 3 as 10 cm per cm can be used. 100 cm and as high as 100 cm per 100 cem.

All of the above solubilities are at 25 ° C and 76Ό mm 30 Hg.

In the following examples, it will be understood, as noted above, that the perfluorinated compounds of the present invention comprise compounds which are fully fluorinated at least 95% by weight, preferably at least 98% and most preferably 100% fluorine.

35, ie. perfluorinated. The compounds less than 100% fluorinated are still highly fluorinated.

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DK 154605 B

Example 1

To 10 cm of perfluoromethyladamantane is added 5 g of egg yolk phospholipid emulsifier. Distilled water is then added to the mixture to a total volume of 50 cm. The solution is filtered through a 10 µm millipore filter and the solution cooled to ca. 0-5 ° C with an ice bath, treated in an ultrasonic apparatus. During this treatment, the optical density of samples of 5 cm is measured at regular intervals until a constant optical density is obtained, which means that the smallest possible particle size in the emulsion is reached. Then the ultrasonic treatment is stopped and a stable aqueous emulsion is obtained with 20% by volume of perfluoromethyladamantane.

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Example 2 3

To 5 cm of perfluoromethyladamantane is added 25 g of egg yolk phospholipid emulsifier. Then distilled water is added to the mixture to a total volume of 500 cm.

The solution is filtered through a 10 µm millipore filter and the solution is homogenized in a Manton-Gaulin homogenizer equipped with a cooler. During homogenization, the optical density of 5 cm emulsion samples is measured at regular intervals until a constant optical density is obtained, which means that the smallest possible particle size in the emulsion is reached. Then the homogenization is stopped and a stable aqueous emulsion is obtained with 10% by volume perfluoromethyladamantane.

Example 3 3

To 100 cm of perfluoroethyl methyladamantane is added 50 g of "Pluronic F68" emulsifier. Then distilled water is added to the mixture to a total volume of 500 cm. The solution is filtered through a 10 µm millipore filter and the solution is homogenized in a Manton-Gaulin homogenizer equipped with a cooler. During homogenization, 7 is measured

DK 1.54605 B

o 3 the optical density of 5 cm emission samples at regular intervals until a constant optical density is reached. Then the homogenization is stopped and a stable aqueous emulsion is obtained with 20% by volume perfluoroethylmethyl-5 adamantane.

Example 4

By proceeding as described in Example 3 but starting from per fluoro otriethyladamantane, a stable aqueous 10 emulsion with 20% by volume perfluorotriethyladamantane is obtained.

Example 5

Proceeding as described in Example 1 but using perfluorotrimethyladamantane, a stable aqueous emulsion is obtained with 10% by volume perfluorotrimethyladamantane.

Example 6

Proceeding as described in Example 2 but using perfluoroethyl dimethyladamantane and "Pluronic F68" as the emulsifier gives a stable aqueous emulsion with 10% by volume perfluoroethyl dimethyl adamantane.

Example 7

Proceeding as described in Example 1 but using perfluoroethyladamantane, a stable aqueous emulsion is obtained with 10% by volume of perfluoroethyladamantane.

Claims (1)

DK 154605 B Patent claims. A process for preparing synthetic blood, emulsifying with water and a non-toxic emulsifier a non-aromatizable perfluorinated compound such that the amount of water in the finished emulsion is greater than 40% by volume, characterized in that as perfluorinated compound is used. alkyl-adamantane, other than dimethyladamantane, preferably 1-methyl-adamantane, the amount of which in the emulsion is 10-30% by volume and having a particle size of approx. 0.001-10 μιη, preferably 50% by weight of the particles having a size of 0.05-0.3 μιη and additionally, if desired, imparting a content 3 3 of 10-100 cm of oxygen (25 ° C, 760 mm Hg). ) per 100 cm of the 15 perfluorinated compound.