FREEZE-DRIED PRODUCT AND GAS-FILLED MICROVESICLES SUSPENSION
A method of manufacturing a suspension of gas-filled microvesicles by reconstituting a freeze-dried product and a suspension obtained according to said method, where the freeze-dried product has been subjected to a thermal treatment.
1 . A method of manufacturing a freeze-dried composition suitable for the preparation of a suspension of stabilized gas-filled microbubbles, said composition comprising:
(i) an amphiphilic material; and (ii) a freeze-drying protecting component; which comprises:
a. preparing a liquid mixture comprising said amphiphilic material and said freeze-drying protecting component in a solvent;
b. freeze-drying the liquid mixture to remove said solvent and obtain a freeze-dried product; and
c. after completion of the freeze-drying of step b, heating said freeze-dried product.
2 . The method according to claim 1 wherein said liquid mixture comprises said amphiphilic material and said freeze-drying protecting component dispersed in an organic solvent.
3 . The method according to claim 1 wherein said liquid mixture comprises said amphiphilic material and said freeze-drying protecting component dispersed in an aqueous emulsion of a water immiscible solvent and water.
4 . The method according to claim 1 wherein said heating step is carried out at a temperature higher than 35° C.
5 . The method according to claim 1 wherein said heating step is carried out at a temperature of 38° C. or higher.
6 . The method according to claim 1 wherein said heating step is carried out at a temperature of 40° C. or higher.
7 . The method according to claim 1 wherein said amphiphilic material comprises a phospholipid.
8 . The method according to claim 7 wherein said amphiphilic material further comprises a fatty acid.
9 . The method according to claim 8 , wherein said amphiphilic material comprises DSPC, DPPG and palmitic acid.
10 . The method according to claim 8 , wherein said amphiphilic material comprises DSPC, DPPE-PEG5000 and palmitic acid.
11 . The method according to claim 1 wherein said freeze-drying protecting component is polyethyleneglycol.
12 . The method according to claim 9 , wherein said freeze-drying protecting component is PEG4000.
13 . The method according to claim 10 , wherein said freeze-drying protecting component is PEG4000.
14 . The method according to claim 12 , wherein said heating step is carried out at a temperature of from 40° C. to 48° C. for at least 8 hours
15 . The method according to claim 13 , wherein said heating step is carried out at a temperature of 36° C. to 45° C.
16 . The method according to claim 1 , wherein said heating in step c is performed for at least eight hours.
17 . The method according to claim 1 , wherein said heating in step c is performed for at least twelve hours.
18 . A freeze-dried product obtained according to the method of claim 1 .
19 . A method of manufacturing a suspension of gas-filled microvesicles which comprises reconstituting a freeze-dried product obtained according to the method of claim 1 with a pharmaceutically acceptable liquid carrier in the presence of a physiologically acceptable gas under gentle agitation.
20 . A suspension of gas-filled microvesicles obtained according to the method of claim 19 .
21 . A method of diagnosing which comprises
(i) administering to a patient a suspension of gas-filled microvesicles obtained according to the method of claim 19 ; and
(ii) detecting an ultrasound signal from a region of interest in said patient.
22 . A method according to claim 21 which comprises ultrasound imaging of the heart.
23 . A method according to claim 21 which comprises ultrasound imaging of the liver.
24 . A method according to claim 21 which comprises ultrasound imaging of a urinary tract.