HK1006147B

HK1006147B - Echo contrast means

Info

Publication number: HK1006147B
Application number: HK98105041.1A
Authority: HK
Inventors: Beller Klaus-Dieter; Linder Rudolf
Original assignee: 奥坦纳医药公司
Priority date: 1991-01-09
Filing date: 1992-01-04
Publication date: 1999-02-12

Description

Technical field

The invention relates to an aqueous preparation for the absorption and stabilization of microgas bubbles for use as an echo-contrast agent.

State of the art

Since ultrasound is strongly reflected by gas bubbles suspended in liquids, aqueous preparations containing stabilized microgas bubbles were proposed as contrast agents for ultrasonic diagnostics at an early stage.

The six manufacturing examples in EP-B-0077752 indicate that aqueous solutions containing a surfactant or a surfactant mixture and a viscosity-enhancing substance have favourable contrasting properties. The surfactants in question are non-ionic lecithins and lecithin fractions and polyoxyethylene polyoxypropylene polymers. The six manufacturing examples in EP-B-0077752 indicate preparations containing a polyoxyethylene polyoxypropylene polymer as a surfactant and a glucose or dextranol or the polyoxyethylene polyoxypropylene polymer itself as a viscosity-enhancing substance. A further stable processing has been proposed for the production of polyoxyethylene polyoxypropylene.

Surprisingly, it has now been found that aqueous preparations containing negatively charged phospholipids in addition to polyoxyethylene polyoxypropylene polymers are particularly suitable for absorbing and stabilizing microgas bubbles.

Description of the invention

The invention therefore relates to aqueous preparations for the absorption and stabilization of microgas bubbles for use as echo contrast agents containing polyoxyethylene polyoxypropylene polymers and negatively charged phospholipids, excluding aqueous solutions of antibodies containing polyoxyethylene polyoxypropylene polymers and phospholipids.

Other objects arise from the claims.

Polyoxyethylene polyoxypropylene polymers are preferred with a mean molecular weight of 8350 to 14000. Polyoxyethylene polyoxypropylene polymers are also known as poloxamers and are available commercially, for example, under the trade name Pluronics® (Wyandotte Chemicals Corp.). The preparations of the invention contain 0.1 to 10%, preferably 1 to 5%, polyoxyethylene polyoxypropylene polymers. The negatively charged phospholipids are in an amount of 0.01 to 5%, preferably 0.5 to 2%.

The phosphatidylglycerol, phosphatidylinositol, phosphatidylethanolamine and phosphatidylserine and their lysoforms are considered to be negatively charged phospholipids. Lysoforms of the negatively charged phospholipids are negative phospholipids containing only one acyl residue. Lysoforms of the negatively charged phospholipids, in which the acyl group is bound to the oxygen of carbon atom 1 of the glycerin molecule, are preferred. Particularly favored negatively charged phospholipids are dipalmitoylphosphatidylglycerol (DPPG) and disterylglycerol (DSPG), with disterylglycerol (DSPG) being particularly preferred.

The present invention is characterized by the fact that, with little mechanical effort, it is possible to produce echo-contrast media containing micro-gas bubbles, which, owing to their high stability, produce a long-lasting contrast and are also excellent for left-hand vision.

The preparations of the invention are not problematic and can be manufactured by placing the individual components together or in succession in water and, if necessary, dissolving them by heating and stirring.

Glycerin, mannitide and ammonium salts of amino acids, preferably glycine, have proved particularly suitable for adjusting the isotonicity of the preparations of the invention.

The production of the microgas bubbles is preferably carried out shortly before administration to the patients to be examined and is carried out in a familiar manner. For example, if the preparation of the invention is provided in a vial, the solution can be drawn up together with the desired amount of air into a regular syringe and injected back into the vial at the highest pressure via a narrow cannula. If necessary, the further drawing and injecting will be repeated several times. Alternatively, the preparations of the invention can also be drawn up and pressed between two syringes through a narrow junction with the quartz or a mixing chamber between the two syringes. The latter procedure leads to particularly informative images, where possible at the same time, which increases the ultrasound image.

All physiologically compatible gases are suitable as gases for the production of the microgas bubbles. The preparations of the invention are foamed with 0.01 to 0.1 ml of gas per ml, preferably with 0.04 to 0.06 ml of gas. They are preferably administered intravenously after the production of the microgas bubbles. Depending on the purpose of use, 1 to 20 ml, preferably 2 to 8 ml, and preferably 5 ml of the preparations of the invention are administered.

It is particularly noteworthy that the preparations of the invention can be dosed at a lower dose because of their increased yield compared to the state of the art.

Examples

After cooling, the distilled water is filled to 100 ml.2. Following the procedure described in example 1, with the difference that 1.0 g of soyaphosphatidylglycerol (Fa. Meyer Lucas, Hamburg) is used instead of DPPG.3. In 80 ml of soyaphosphatidylglycerol, 1.0 g of glycerol is used. Dilute with ammonia and add a solution of pH 6 to 80 to 74. In the water, the difference is 80 to 80 g. The solution is then diluted to pH 3.

Comparative tests

The studies were conducted in waking male beagles (18.2-30.5 kg body weight) and each dog received 5 ml of the following contrast preparations: A:One solution for infusion containing 35 g of cross-linked polypeptides per 1000 ml of plasma replacement (Haemaccel® by Fa. Behringwerke) B:Echovist® (echokontracts by Fa. Schering) C:An aqueous solution containing 4% by weight of poloxamer 188 (Pluronic® F68) and 4% by weight of glucose (Example 1 in EP 0 077 752) D:An aqueous solution containing 2% by weight of poloxamer and 4% by weight of glucose (Example 2 in EP 0 077 752) E:An aqueous solution containing 1% by weight of poloxamer and 4% by weight of glucose (Example 3 in EP 0 077 752) F:Preparation according to Example 5 The solutions A, C, D, E and F are drawn up without air in a first syringe, which is then connected to the free end of a 0.18 ml air-containing mixing chamber firmly connected to a second syringe, and pumped five times from the first syringe through the mixing chamber into the second syringe and back immediately before application.

Commercially available contrast agent B is prepared according to the instructions in the package leaflet.

The echocardiographic ultrasound recordings were made with a Sonoscope 4 ultrasonic device with a mechanical head at 3.5 MHz. The video prints of the resulting ultrasound images were densitometrically evaluated for contrast intensity. The densitometer (Gretag D182) used determines the changes in brightness in 100 steps in a range of 0.00 to 2.50 density units. The calibration is carried out using the calibration reference provided by the manufacturer in accordance with DIN 16536 (calibration reference), assigning the brightest white the value of 1.64 and the darkest black the value of 0.00. The average of four individual provisions on an area of 1 cm x 1 cm gives the value for each calibrated preparation.

The results obtained are given in the following table. Other

5 ml	rechter Ventrikel			linker Ventrikel
	Kontrast	Intensität		Kontrast	Intensität
		max	10sec		max	10sec
A	ja	1,18	0,86	nein	0,00	0,00
B	ja	1,09	0,65	nein	0,00	0,00
C	ja	1,20	0,78	nein	0,00	0,00
D	ja	1,23	0,87	nein	0,00	0,00
E	ja	1,22	0,93	nein	0,00	0,00
F	ja	1,19	0,82	ja	0,78	0,72
Intensität in Density Units (DU)

The results show that, unlike the echo-contrast agents, the products of the present invention are pulmonary and therefore very suitable for left-sided cardiac diagnostics.

The micro bubbles of the echo-contrasting agents of the invention have been found to have a considerable affinity for the internal surfaces of vessels and cavities of the body, which results in a much better and thus more informative representation of the outlines of vessels and cavities than is possible with the contrasting agents of the present technology.

Figures 1 and 2 show the results of an experiment to demonstrate this novel contrast of surface structures.

Figure 1 shows the echocardiographic picture of the endocard of a wakeful beagle in the so-called four-chamber view immediately before the first contrast after administration of 1 ml of echocontrast agent as in Example 1.

Figure 2 shows the endocard of the animal after the echolocator has been washed out of the heart.

The comparison of the two figures shows that the echo-contrast devices of the invention allow an unexpected drawing of the endocard, which is a great source of information for diagnostic purposes.

Claims

Process for the preparation of aqueous preparations for receiving and stabilising micro bubbles for use as echo contrast media with the exception of aqueous solutions of antibodies containing polyoxyethylene/polyoxypropylene polymers and phospholipids, characterised in that polyoxyethylene/polyoxypropylene polymers are dissolved in water together with negatively charged phospholids.
Process according to claim 1, characterised in that polyoxyethylene/polyoxypropylene polymers with an average molecular weight of 8,350 to 10 % (weight/volume) are used.
Process according to claim 1, characterised in that polyoxyethylene/polyoxypropylene polymers are dissolved in an amount of 0,1 to 10 % (weight/volume).
Process according to claim 3, characterised in that polyoxyethylene/polyoxypropylene polymers are dissolved in an amount of 1 to 5 % (weight/volume).
Process according to claim 1, characterised in that phosphatidylglycerols, phosphatidylinositols, phosphatidylethanolamines and/or phosphatidylserines are used as negatively charged phospholipds.
Process according to claim 5, characterised in that distearoylphosphatidylglycerol is used as negatively charged phospholipid.
Process according to claim 1, characterised in that negatively charged phospholipid is dissolved in an amount of 0.01 to 5 % (weight/volume).
Process according to claim 1, characterised in that 3 % (weight/volume) of polyoxyethylene/polyoxypropylene polymers with an average molecular weight of 8,400 and 1 % (weight/volume) of distearoylphosphatidylglycerol are dissolved.
Process according to claim 1, characterised in that the negatively charged phospholipid(s) are used as lyso form.
Process according to claim 1, characterised in that in addition customary auxiliaries for achieving isotonicity are dissolved in water.