CA2156922C - Fluorocarbon emulsions with reduced pulmonary gas-trapping properties - Google Patents
Fluorocarbon emulsions with reduced pulmonary gas-trapping properties Download PDFInfo
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Abstract
A fluorocarbon emulsion which exhibits reduced pulmonary gas-trapping properties in species-sensitive laboratory animals is disclosed.
Additionally, the fluorocarbon component(s) exhibit short organ retention time(s). The emulsion includes an aqueous phase, an emulsifier, and a fluorocarbon (or fluorocarbon composition), having a vapor pressure of less than about 8 torr to reduce pulmonary gas-trapping, and having an organ retention half life of less than about 6 weeks and more preferably less than about 3 to 4 weeks.
Additionally, the fluorocarbon component(s) exhibit short organ retention time(s). The emulsion includes an aqueous phase, an emulsifier, and a fluorocarbon (or fluorocarbon composition), having a vapor pressure of less than about 8 torr to reduce pulmonary gas-trapping, and having an organ retention half life of less than about 6 weeks and more preferably less than about 3 to 4 weeks.
Description
'110 94/21227 2156922 PCT/US94/02222 FLUOROCARBON EMULSIONS WITH REDUCED PULMONARY
GAS-TRAPPING PROPERTIES
Background or th~ Invention The present invention relates to emulsions comprising highly fluorinated or perfluorinated compounds. More particularly, it relates to fluorocarbon emulsions exhibiting reduced pulmonary gas-trapping properties.
Fluorocarbon emulsions find uses as therapeutic and diagnostic agents. Most therapeutic uses of fluorocarbons are related to the remarkable oxygen-carrying capacity of these compounds. One commercial biomedical fluorocarbon emulsion, Fluosol (Green Cross Corp., Osaka, Japan), is presently used as an oxygen carrier to enhance oxygen delivery to the myocardium during percutaneous transluminal coronary is angioplasty (Fluosol, Summary Basis of Approval, Reference No.
OB-NDA86-0909, Dec. 1989). Fluorocarbon emulsions have also been used in diagnostic applications such as imaging.
Radiopaque fluorocarbons such as perflubron (perfluorooctyl bromide or C8F17Br) are particularly useful for this purpose.
Increased pulmonary residual volume (IPRV) has been observed in association with the intravenous administration of various perfluorocarbon emulsions in certain animal species.
While the direct correlation between IPRV and pulmonary dysfunction has not been positively identified, dysfunction (including reduced arterial P02, signs of respiratory distress, and even lethality) has been observed on occasions in certain sensitive animal species in which IPRV was later identified.
IPRV occurs as a result of gas-trapping within the pulmonary system, and prevents the normal deflation of lungs when intrathoracic pressure is equalized to ambient pressure such as during necropsy of an animal. It is believed that gas-trapping occurs as a consequence of foam or bubble formation in the lungs. It is noted that under normal circumstances, bubbles or liquid bridges form and disappear spontaneously within alveoli without a gas-trapping effect.
It is believed, however, that IPRV occurs when these bubbles grow in the presence of fluorocarbon vapors, trapping larger amounts ot air within the lung. As stated above, if bubble formation continues, pulmonary dysfunction can result (in certain animal species). IPRV depends on the vapor pressure of the fluorocarbon component(s), with lower vapor pressure fluorocarbons not exhibiting the phenomenon. Diminution of the vapor pressure of the fluorocarbon component(s) also plays a critical role in stabilizing the emulsion droplets against Ostwald ripening, the key destabilizing mechanism at work in small particle fluorocarbon emulsions. The prior art has described fluorocarbon emulsion formulations designed to inhibit Ostwald ripening. See, e.g. Davis et al., U.S. Patent No. 4,859,363; Meinert, U.S. Patent No. 5,120,731; Kabalnov et al., Kolloidn Zh., 48: 27-32 (1986). These formulations contain a mixture of two fluorocarbon components, the secondary fluorocarbon component having a significantly higher molecular weight, and lower vapor pressure relative to the primary fluorocarbon component.
Following intravenous administration, fluorocarbon emulsion particles are taken up and temporarily retained by cells of the reticuloendothelial system (RES). It is desirable to minimize this retention time (all references to organ half-life or organ retention which follow refer specifically to retention in the RES organs, principally liver and spleen). Unfortunately, when the prior art included higher molecular weight fluorocarbons in fluorocarbon emulsions, organ retention times were also increased considerably. Organ retention times for most fluorocarbons bear an exponential relationship to the molecular weight of the fluorocarbon and are critically dependent on dose and animal species. See J.G. Riess, Artificial Organs 8: 44, 49-51 (1984); J.G. Riess, International Symposium on Blood Substitutes, Bari, Italy: Jun. 19-20, 1987, Proceedings pp.
135-166.
GAS-TRAPPING PROPERTIES
Background or th~ Invention The present invention relates to emulsions comprising highly fluorinated or perfluorinated compounds. More particularly, it relates to fluorocarbon emulsions exhibiting reduced pulmonary gas-trapping properties.
Fluorocarbon emulsions find uses as therapeutic and diagnostic agents. Most therapeutic uses of fluorocarbons are related to the remarkable oxygen-carrying capacity of these compounds. One commercial biomedical fluorocarbon emulsion, Fluosol (Green Cross Corp., Osaka, Japan), is presently used as an oxygen carrier to enhance oxygen delivery to the myocardium during percutaneous transluminal coronary is angioplasty (Fluosol, Summary Basis of Approval, Reference No.
OB-NDA86-0909, Dec. 1989). Fluorocarbon emulsions have also been used in diagnostic applications such as imaging.
Radiopaque fluorocarbons such as perflubron (perfluorooctyl bromide or C8F17Br) are particularly useful for this purpose.
Increased pulmonary residual volume (IPRV) has been observed in association with the intravenous administration of various perfluorocarbon emulsions in certain animal species.
While the direct correlation between IPRV and pulmonary dysfunction has not been positively identified, dysfunction (including reduced arterial P02, signs of respiratory distress, and even lethality) has been observed on occasions in certain sensitive animal species in which IPRV was later identified.
IPRV occurs as a result of gas-trapping within the pulmonary system, and prevents the normal deflation of lungs when intrathoracic pressure is equalized to ambient pressure such as during necropsy of an animal. It is believed that gas-trapping occurs as a consequence of foam or bubble formation in the lungs. It is noted that under normal circumstances, bubbles or liquid bridges form and disappear spontaneously within alveoli without a gas-trapping effect.
It is believed, however, that IPRV occurs when these bubbles grow in the presence of fluorocarbon vapors, trapping larger amounts ot air within the lung. As stated above, if bubble formation continues, pulmonary dysfunction can result (in certain animal species). IPRV depends on the vapor pressure of the fluorocarbon component(s), with lower vapor pressure fluorocarbons not exhibiting the phenomenon. Diminution of the vapor pressure of the fluorocarbon component(s) also plays a critical role in stabilizing the emulsion droplets against Ostwald ripening, the key destabilizing mechanism at work in small particle fluorocarbon emulsions. The prior art has described fluorocarbon emulsion formulations designed to inhibit Ostwald ripening. See, e.g. Davis et al., U.S. Patent No. 4,859,363; Meinert, U.S. Patent No. 5,120,731; Kabalnov et al., Kolloidn Zh., 48: 27-32 (1986). These formulations contain a mixture of two fluorocarbon components, the secondary fluorocarbon component having a significantly higher molecular weight, and lower vapor pressure relative to the primary fluorocarbon component.
Following intravenous administration, fluorocarbon emulsion particles are taken up and temporarily retained by cells of the reticuloendothelial system (RES). It is desirable to minimize this retention time (all references to organ half-life or organ retention which follow refer specifically to retention in the RES organs, principally liver and spleen). Unfortunately, when the prior art included higher molecular weight fluorocarbons in fluorocarbon emulsions, organ retention times were also increased considerably. Organ retention times for most fluorocarbons bear an exponential relationship to the molecular weight of the fluorocarbon and are critically dependent on dose and animal species. See J.G. Riess, Artificial Organs 8: 44, 49-51 (1984); J.G. Riess, International Symposium on Blood Substitutes, Bari, Italy: Jun. 19-20, 1987, Proceedings pp.
135-166.
There is a need for perfluorocarbon emulsions that do not exhibit, cr exhibit reduced pulmonary gas-trapping properties, and alsc have a short organ retention time. Accordingly, this invention provides fluorocarbon emulsions having these characteristics.
Summary of the Invention The present invention involves fluorocarbon emulsions which unexnectedly exhibit both reduced pulmonary gas-trapping properties, and a short RES organ retention time.
Thus, in accordance with the present invention, there is provided a fluorocarbon emulsion which has the fo,~~~lewing properties: (1) the fluorocarbon component(s) has (have) a vapor pressure at 37 degrees celsius of less than 2.67 kPa (20 torr) , preferably less than 1.33 kPa (10 torr) , and mcst preferably less than 1.07 kPa (8 torr), in order to preclude pulmonary gas-trapping; and (2) the fluorocarbon component (s) has (have) organ half-lives significantly less than would be predicted for their molecular weight, preferably less than about 6 weeks, and more preferably less than about 3 to 4 weeks.
In one preferred embodiment, the emulsion comprises an aqueous phase, an emulsifying agent, and a single low vapor pressure, lipophilic fluorocarbon. It has been determined that there are few fluorocarbons presently known which exhibit the above stated characteristics. Several fluorocarbons which appear suitable as a single lipophilic fluorocarbon component to eliminate IPRV are listed in Table II, and include:
CF3 (CF2) BBr, (CF3) 2CF (CF2) 3CF (CF.,) CF2Br, F-octyl ethane and F-bromoethers.
In another preferred embodiment, the fluorocarbon is a mixture of two or more fluorocarbons (the "fluorocarbon phase") The emulsion may contain a fluorocarbon composition where the fluorocarbon phase comprises from about 50 o to about 99.9o w/w of a first fluorocarbon, and from about 0.1o to about 501 w/w of a second fluorocarbon having a vapor pressure less than the first fluorocarbon, and which includes at least one lipophilic moiety. In parzicular, in the second AMENDED SHEET
Summary of the Invention The present invention involves fluorocarbon emulsions which unexnectedly exhibit both reduced pulmonary gas-trapping properties, and a short RES organ retention time.
Thus, in accordance with the present invention, there is provided a fluorocarbon emulsion which has the fo,~~~lewing properties: (1) the fluorocarbon component(s) has (have) a vapor pressure at 37 degrees celsius of less than 2.67 kPa (20 torr) , preferably less than 1.33 kPa (10 torr) , and mcst preferably less than 1.07 kPa (8 torr), in order to preclude pulmonary gas-trapping; and (2) the fluorocarbon component (s) has (have) organ half-lives significantly less than would be predicted for their molecular weight, preferably less than about 6 weeks, and more preferably less than about 3 to 4 weeks.
In one preferred embodiment, the emulsion comprises an aqueous phase, an emulsifying agent, and a single low vapor pressure, lipophilic fluorocarbon. It has been determined that there are few fluorocarbons presently known which exhibit the above stated characteristics. Several fluorocarbons which appear suitable as a single lipophilic fluorocarbon component to eliminate IPRV are listed in Table II, and include:
CF3 (CF2) BBr, (CF3) 2CF (CF2) 3CF (CF.,) CF2Br, F-octyl ethane and F-bromoethers.
In another preferred embodiment, the fluorocarbon is a mixture of two or more fluorocarbons (the "fluorocarbon phase") The emulsion may contain a fluorocarbon composition where the fluorocarbon phase comprises from about 50 o to about 99.9o w/w of a first fluorocarbon, and from about 0.1o to about 501 w/w of a second fluorocarbon having a vapor pressure less than the first fluorocarbon, and which includes at least one lipophilic moiety. In parzicular, in the second AMENDED SHEET
fluorocarbon, the lipophilic moiety or moieties are advantageouslv 3r, Cl, I, H, CHõ or a saturated or unsaturated hydrocarbon chain of 2 or 3 carbon atoms. In one preferred embodiment, the second fluorocarbon is an aliphatic perfluorocarbon having the general formula CnFZn.,R or C.;FznR,, wherein n is an integer from 9 to 12 and R is the lipophilic moiety. In various preferred embodiments, the second fluorocarbon is selected from the group consisting of perf luorodecyl bromide, C,oF._CH=CH2 , or C, oF21CHzCH, , or -inear or branched brominated perfluorinated alkyl ethers. Mosz preferably, the second fluorocarbon comprises perfluorodecyl bromide. It is desirable that each second fluorocarbon has a molecular weight greater than about 550 Daltons. Pursuar.t to an alternative definition of the second fluorocarbon, each second fluorocarbon has a critical solution temperature in hexane at least 10 C lower than that of a fully fluorinated fluorocarbon having substantially the same molecular weich7-(i.e., a molecular weight within 10, and preferably within 3, 4, or 5 daltons). In preferred emu,_sions, the discontinuous fluorocarbon phase comprises from about 60 o to about 99 . 5% w/w of the first fluorocarbon, and from about 0.5% to about 400 w/w of the second fluorocarbon; more preferably from about 60 0 to about 8 0 o w/w of the f i rst f luorocarbon, and from about 201 to about 40o w/w of the second fluorocarbon. The first fluorocarbon component in these mixtures has a molecular weight from about 460 to 550 Daltons, and has a half-life in the organs of less than about 4 weeks, more preferab7 _y less than about 2 or 3 weeks, and most preferably 7 days or less.
In particular, the fluorocarbon phase preferably comprises a suitable mixture of perfluorooctyl bromide (PFOE, USA:'v perflubron) and perfluorodecyl bromide (PFDB).
Focusing specifically on particular embodiments, one aspect of the present invention is a fluorocarbon emulsion exhibiting reduced pulmonary gas-trapping properties, comprising an aqueous phase, an emulsifying agent, and a liquid fluorocarbon phase having a vapor pressure of less than about 2.67 kPa (20 torr) at 37 C, having an organ half-life of AMENDED sHEET
In particular, the fluorocarbon phase preferably comprises a suitable mixture of perfluorooctyl bromide (PFOE, USA:'v perflubron) and perfluorodecyl bromide (PFDB).
Focusing specifically on particular embodiments, one aspect of the present invention is a fluorocarbon emulsion exhibiting reduced pulmonary gas-trapping properties, comprising an aqueous phase, an emulsifying agent, and a liquid fluorocarbon phase having a vapor pressure of less than about 2.67 kPa (20 torr) at 37 C, having an organ half-life of AMENDED sHEET
less than about 6 weeks, and having a lipophilic component, the fluorocarbon phase comprising a mixture of at least two fluorocarbons in a weight'ratio of from about 20:1 to about i:20. Preferably, the fluorocarbon phase comprises a first fluorocarbon having an organ half-life of less than about 4 weeks, and a second fluorocarbon having a vapor pressure less than the first fluorocarbon. In one embodiment, the first fluorocarbon has a molecular weight of about 460 te 550 Daltons, and the second fluorocarbon has a molecular weight of10 about 560 to 700 Daltons. In another embodiment, the fluorocarbon phase has a vapor pressure at 37 C of less than about 1.33 kPa (10 torr), preferably less than about 1.07 kP-=
( 8 tcrr ) .
In another embodiment, the invention is a fluorocarbon emulsion exhibiting reduced pulmonary gas-trapping properties, comprisi ng an aqueous phase, an emulsifier, and a fluorocarbon phase including at least 10% weight by volume of F-decyl bromide. In this emulsion, the fluorocarbon phase may advantageously additionally comprise F-octyl bromide, and the F-octyl bromide is preferably present in the fluorocarbor_ phase at about 45% to 800 or 90% weight per volume, and the F-decyl bromide is present in the fluorocarbon phase at about i0 to 55% weight per volume.
Still another embodiment of the zresent invention is a fluorocarbon emulsion exhibiting reduced pulmonary gas trapping, comprising an aqueous phase, an emulsifier, and a fluorocarbon phase consisting essentially of a single low vapor pressure, lipophilic fluorocarbon having an organ half-life of less than about 6 weeks, and a vapor pressure at 37 C
of less than 1.33 kPa (10 torr). Suitable fluorocarbons for the fluorocarbon phase are F-octyl ethane and F-decyl ethane.
Preferably, the fluorocarbon has an organ half-life of less than 3 to 4 weeks. In a preferred embodiment, the fluorocarbon has a vapor pressure at 37 C of less than 1.07 kPa (8 torr). In another embodiment, the invention is a method of preparing a fluorocarbon emulsion for intravenous administration to a patient, by forming an emulsion of an AMENDED SHEET
215 6 9,22 aqueous phase, an emulsifier, and a first fluorocarbon in a fluorocarbon phase wherein the vapor pressure of zhe fluorocarbon phase is greater than about 1.07 k?a (8 torr) at 37 C, the improvement comprising reducin~ the pulmonary gas trapping effect of the emulsion upon intravenous administration' by providing in combination with the first fluorocarbon in the fluorocarbon phase an effective amount of a second fluorocarbon, wherein the addition of the second fluorocarbon reduces the vapor pressure of the fluorocarbon phase at 37 C to less than about 1.07 kPa (8 torr), wherein the fluorocarbon phase has a melting point less than about 37 C and an organ retention half-life less than about 4 weeks.
As above, the second fluorocarbon preferably includes a lipophilic moiety, and more preferably is a bromcfluorocarbon.
Finally, the invention includes a method for administering a fluorocarbon emulsion to a mammal, wherein the emulsion comprises an aaueous phase, an emulsifier, and a first fluorocarbon in a fluorocarbon phase wherein the vapor pressure of the fluoracarbon phase is greater than about i.07 kPa (8 torr) at 37 C, and wherein the improvement comprises reducing the pulmonary gas trapping effect of the emulsion upon intravenous administration by providing in combinatior_ with the first fluorocarbon in the fluorocarbon phase an effective amount of a second fluorocarbon, wherein the addition of the second fluorocarbon reduces the vapor pressure of the fluorocarbon phase at 37 C to less than about 1.07 kPa (8 torr), wherein the fluorocarbon phase has a melting point less than about 37 C=and an organ retention half-life less than about 4 weeks.
As noted, one of the criteria for the emulsions of this invention is that the fluorocarbon component(s) exhibit a short organ retention time. One low vapor pressure lipophilic fluorocarbon, perfluorodecyl bromide, for example, has a RES
half life in vivo of approximately 23 days, while those of nonlipophilic perfluorocarbons having about the same molecular weight vary from about 60 to 300 days (See Table I/Figure AMENDED SHEET
( 8 tcrr ) .
In another embodiment, the invention is a fluorocarbon emulsion exhibiting reduced pulmonary gas-trapping properties, comprisi ng an aqueous phase, an emulsifier, and a fluorocarbon phase including at least 10% weight by volume of F-decyl bromide. In this emulsion, the fluorocarbon phase may advantageously additionally comprise F-octyl bromide, and the F-octyl bromide is preferably present in the fluorocarbor_ phase at about 45% to 800 or 90% weight per volume, and the F-decyl bromide is present in the fluorocarbon phase at about i0 to 55% weight per volume.
Still another embodiment of the zresent invention is a fluorocarbon emulsion exhibiting reduced pulmonary gas trapping, comprising an aqueous phase, an emulsifier, and a fluorocarbon phase consisting essentially of a single low vapor pressure, lipophilic fluorocarbon having an organ half-life of less than about 6 weeks, and a vapor pressure at 37 C
of less than 1.33 kPa (10 torr). Suitable fluorocarbons for the fluorocarbon phase are F-octyl ethane and F-decyl ethane.
Preferably, the fluorocarbon has an organ half-life of less than 3 to 4 weeks. In a preferred embodiment, the fluorocarbon has a vapor pressure at 37 C of less than 1.07 kPa (8 torr). In another embodiment, the invention is a method of preparing a fluorocarbon emulsion for intravenous administration to a patient, by forming an emulsion of an AMENDED SHEET
215 6 9,22 aqueous phase, an emulsifier, and a first fluorocarbon in a fluorocarbon phase wherein the vapor pressure of zhe fluorocarbon phase is greater than about 1.07 k?a (8 torr) at 37 C, the improvement comprising reducin~ the pulmonary gas trapping effect of the emulsion upon intravenous administration' by providing in combination with the first fluorocarbon in the fluorocarbon phase an effective amount of a second fluorocarbon, wherein the addition of the second fluorocarbon reduces the vapor pressure of the fluorocarbon phase at 37 C to less than about 1.07 kPa (8 torr), wherein the fluorocarbon phase has a melting point less than about 37 C and an organ retention half-life less than about 4 weeks.
As above, the second fluorocarbon preferably includes a lipophilic moiety, and more preferably is a bromcfluorocarbon.
Finally, the invention includes a method for administering a fluorocarbon emulsion to a mammal, wherein the emulsion comprises an aaueous phase, an emulsifier, and a first fluorocarbon in a fluorocarbon phase wherein the vapor pressure of the fluoracarbon phase is greater than about i.07 kPa (8 torr) at 37 C, and wherein the improvement comprises reducing the pulmonary gas trapping effect of the emulsion upon intravenous administration by providing in combinatior_ with the first fluorocarbon in the fluorocarbon phase an effective amount of a second fluorocarbon, wherein the addition of the second fluorocarbon reduces the vapor pressure of the fluorocarbon phase at 37 C to less than about 1.07 kPa (8 torr), wherein the fluorocarbon phase has a melting point less than about 37 C=and an organ retention half-life less than about 4 weeks.
As noted, one of the criteria for the emulsions of this invention is that the fluorocarbon component(s) exhibit a short organ retention time. One low vapor pressure lipophilic fluorocarbon, perfluorodecyl bromide, for example, has a RES
half life in vivo of approximately 23 days, while those of nonlipophilic perfluorocarbons having about the same molecular weight vary from about 60 to 300 days (See Table I/Figure AMENDED SHEET
7). This distinction is critical; it spells the difference between formulations which are physiologically acceptable and those which are not. Note that none of the prior art low vapor pressure fluorocarbons are lipophilic; thus, none share the advantageous properties of the present invention. For example, with reference to Table I and Figure 3, the fluorocarbons of the present invention all have critical solution temperatures (CSTs) and projected organ retention times much lower than those of the prior art fluorocarbons of Davis, et al., Kabalnov, and Meinert.
Aside from the fluorocarbons of the present invention, conventional fluorocarbons exhibit a direct correlation between retention time in RES organs and molecular weight. Also, aside from the lipophilic fluorocarbons used in the present invention, the perfluorochemical structure has little effect on the strong retention time/molecular weight relationship. Thus, the presence of heteroatoms or cyclic structure has little effect on organ retention time.
A particularly preferred emulsifier for use in the present invention is egg yolk phospholipid, and preferred amounts of this emulsifier are 1% -10% w/v.
Also preferred are the fluorinated surfactants.
According to an aspect of the invention, there is provided a fluorocarbon emulsion exhibiting reduced pulmonary gas-trapping properties, comprising:
an aqueous phase;
an emulsifying agent; and a liquid fluorocarbon phase having a vapor pressure of less than about 2.67 kPa (20 torr) at 37 C, having an organ half-life of less than about 6 weeks, and having a lipophilic component, said fluorocarbon phase comprising a mixture of at least two fluorocarbons in a weight ratio of from about 20:1 to about 1:20.
According to another aspect of the present invention, there is provided a fluorocarbon emulsion exhibiting reduced pulmonary gas-trapping properties, comprising:
an aqueous phase;
an emulsifier; and a fluorocarbon phase including at least 10% weight by volume of F-decyl AL bromide.
-7a-According to another aspect of the present invention, there is provided a fluorocarbon emulsion exhibiting reduced pulmonary gas trapping, comprising:
an aqueous phase;
an emulsifier; and a fluorocarbon phase consisting essentially of a single low vapor pressure; fluorocarbon phase having an organ half-life of less than about 6 weeks, and a vapor pressure at 37 C of less than 1.33 kPa (10 torr).
According to another aspect of the present invention, there is provided a method of preparing a fluorocarbon emulsion for intravenous administration to a patient, by forming an emulsion of an aqueous phase, an emulsifier, and a first fluorocarbon in a fluorocarbon phase wherein the vapor pressure of the fluorocarbon phase is greater than about 1.07 kPa (8 torr) at 37 C, the improvement comprising:
reducing the pulmonary gas trapping effect of the emulsion upon intravenous administration by providing in combination with the first fluorocarbon in the fluorocarbon phase an effective amount of a second fluorocarbon, wherein the addition of the second fluorocarbon reduces the vapor pressure of the fluorocarbon phase at 37 C to less than about 1.07 kPa (8 torr), wherein the fluorocarbon phase has a melting point less than about 37 C and an organ retention half-life less than about 4 weeks.
According to a further aspect of the present invention, there is provided use of a first fluorocarbon in combination with an effective amount of a second fluorocarbon to reduce the pulmonary gas trapping effect of a fluorocarbon emulsion in a mammal, wherein the emulsion comprises an aqueous phase, an emulsifier, the first fluorocarbon in a fluorocarbon phase wherein the vapour pressure of the fluorocarbon phase is greater than about 1.07 kPa (8 torr) at 37 C, and the effective amount of the second fluorocarbon wherein the second -7b-fluorocarbon reduces the vapour pressure of the fluorocarbon phase at 37 C to less than about 1.07 kPa (8 torr), wherein the fluorocarbon phase has a melting point less than about 37 C and an organ retention half-life less than about 4 weeks.
According to a yet further aspect of the present invention, there is provided a medicament for use in reducing the pulmonary gas trapping effect of a fluorocarbon emulsion comprising an aqueous phase, an emulsifier, and a first fluorocarbon in a fluorocarbon phase, wherein the vapor pressure of said fluorocarbon phase is greater than about 1.07 kPa (8 torr) at 37 C, the improvement comprising:
an effective amount of a second fluorocarbon in combination with said first fluorocarbon, wherein the second fluorocarbon reduces the vapor pressure of the fluorocarbon phase at 37 C to less than about 1.07 kPa (8 torr), wherein the fluorocarbon phase has a melting point less than about 37 C and an organ retention half-life less than about 4 weeks.
Brief Description of the Drawings FIG. 1 is a graph which illustrates the increase in lung volume which occurs in rats as a result of pulmonary gas trapping following intravenous administration at a dose of 5.4 g PFC/kg. The formulations tested are concentrated (90% w/v) fluorocarbon emulsions stabilized by 4% egg yolk phospholipid. The conversion factor for torr to kPa is 1 torr = 0.13329 kPa.
FIG. 2 is a graph which illustrates the increase in lung volume which occurs in rabbits as a result of pulmonary gas trapping following intravenous administration at a dose of 5.4 g PFC/kg. The formulations tested are concentrated (90% w/v) fluorocarbon emulsions stabilized by 4% egg yolk phospholipid.
Aside from the fluorocarbons of the present invention, conventional fluorocarbons exhibit a direct correlation between retention time in RES organs and molecular weight. Also, aside from the lipophilic fluorocarbons used in the present invention, the perfluorochemical structure has little effect on the strong retention time/molecular weight relationship. Thus, the presence of heteroatoms or cyclic structure has little effect on organ retention time.
A particularly preferred emulsifier for use in the present invention is egg yolk phospholipid, and preferred amounts of this emulsifier are 1% -10% w/v.
Also preferred are the fluorinated surfactants.
According to an aspect of the invention, there is provided a fluorocarbon emulsion exhibiting reduced pulmonary gas-trapping properties, comprising:
an aqueous phase;
an emulsifying agent; and a liquid fluorocarbon phase having a vapor pressure of less than about 2.67 kPa (20 torr) at 37 C, having an organ half-life of less than about 6 weeks, and having a lipophilic component, said fluorocarbon phase comprising a mixture of at least two fluorocarbons in a weight ratio of from about 20:1 to about 1:20.
According to another aspect of the present invention, there is provided a fluorocarbon emulsion exhibiting reduced pulmonary gas-trapping properties, comprising:
an aqueous phase;
an emulsifier; and a fluorocarbon phase including at least 10% weight by volume of F-decyl AL bromide.
-7a-According to another aspect of the present invention, there is provided a fluorocarbon emulsion exhibiting reduced pulmonary gas trapping, comprising:
an aqueous phase;
an emulsifier; and a fluorocarbon phase consisting essentially of a single low vapor pressure; fluorocarbon phase having an organ half-life of less than about 6 weeks, and a vapor pressure at 37 C of less than 1.33 kPa (10 torr).
According to another aspect of the present invention, there is provided a method of preparing a fluorocarbon emulsion for intravenous administration to a patient, by forming an emulsion of an aqueous phase, an emulsifier, and a first fluorocarbon in a fluorocarbon phase wherein the vapor pressure of the fluorocarbon phase is greater than about 1.07 kPa (8 torr) at 37 C, the improvement comprising:
reducing the pulmonary gas trapping effect of the emulsion upon intravenous administration by providing in combination with the first fluorocarbon in the fluorocarbon phase an effective amount of a second fluorocarbon, wherein the addition of the second fluorocarbon reduces the vapor pressure of the fluorocarbon phase at 37 C to less than about 1.07 kPa (8 torr), wherein the fluorocarbon phase has a melting point less than about 37 C and an organ retention half-life less than about 4 weeks.
According to a further aspect of the present invention, there is provided use of a first fluorocarbon in combination with an effective amount of a second fluorocarbon to reduce the pulmonary gas trapping effect of a fluorocarbon emulsion in a mammal, wherein the emulsion comprises an aqueous phase, an emulsifier, the first fluorocarbon in a fluorocarbon phase wherein the vapour pressure of the fluorocarbon phase is greater than about 1.07 kPa (8 torr) at 37 C, and the effective amount of the second fluorocarbon wherein the second -7b-fluorocarbon reduces the vapour pressure of the fluorocarbon phase at 37 C to less than about 1.07 kPa (8 torr), wherein the fluorocarbon phase has a melting point less than about 37 C and an organ retention half-life less than about 4 weeks.
According to a yet further aspect of the present invention, there is provided a medicament for use in reducing the pulmonary gas trapping effect of a fluorocarbon emulsion comprising an aqueous phase, an emulsifier, and a first fluorocarbon in a fluorocarbon phase, wherein the vapor pressure of said fluorocarbon phase is greater than about 1.07 kPa (8 torr) at 37 C, the improvement comprising:
an effective amount of a second fluorocarbon in combination with said first fluorocarbon, wherein the second fluorocarbon reduces the vapor pressure of the fluorocarbon phase at 37 C to less than about 1.07 kPa (8 torr), wherein the fluorocarbon phase has a melting point less than about 37 C and an organ retention half-life less than about 4 weeks.
Brief Description of the Drawings FIG. 1 is a graph which illustrates the increase in lung volume which occurs in rats as a result of pulmonary gas trapping following intravenous administration at a dose of 5.4 g PFC/kg. The formulations tested are concentrated (90% w/v) fluorocarbon emulsions stabilized by 4% egg yolk phospholipid. The conversion factor for torr to kPa is 1 torr = 0.13329 kPa.
FIG. 2 is a graph which illustrates the increase in lung volume which occurs in rabbits as a result of pulmonary gas trapping following intravenous administration at a dose of 5.4 g PFC/kg. The formulations tested are concentrated (90% w/v) fluorocarbon emulsions stabilized by 4% egg yolk phospholipid.
FIG. 3 represents a plot of fluorocarbon molecular weight (g/mol) versus critical solution temperature in hexane ( K) for various fluorocarbons including the prior art emul-,--ion stabilizers proposed :y Davis, Meinert, and Kabalnov.
F IG. 4 is a plot illustrating the organ half -life in days vs. molecular weight of various fluorocarbons in g/mol. I'he plot includes a lower molecular weight cutoff which is rela--ed to the formation of gas emboli for fluorocarbons with vapor pressures greater than 2.67 kPa (20 torr). The plot also includes an upper molecular weight cutoff which is related tlo compounds having organ retention times of less than 4 weeks.
FIG. 5 is a plot illustrating the oraan half-life in days vs. molecular weight cf various fluorocarbons in g/mol. The plot includes a lower molecular weight cutoff of 520 g/mol to take into account pulmonary gas trapping (i.e. limit to less than 1.07 kPa (8 torr)).
FIG. 6 is a graph of fluorocarbon vapor pressure in tcrr at 37 degrees celsius for various mole fractions in mix-:ures of perfiucrooctyl bromide (PFOB) and perfluorodecyl hromide (PFDB).
FIG. 7 is a table listing various properties of fluorocarbons.
Descrintion of the Preferred Embodiments I. Introduction The fluorocarbon emulsions of the present invention comprise two phases: a continuous aqueous phase and a discontinuous fluorocarbon phase. Osmotic agents and buffers, generally, are also included in the continuous phase to maintain .osmolality and pH to promote physiological acceptability.
The discontinuous phase of modern fluorocarbon emulsions for therapeutic use generally comprises from 20% w/v to up to 125% w/v of a fluorocarbon or a highly fluorinated compound (hereinafter referred as a "fluorocarbon" or a "perfluorocarbon"). As used herein, the expression "weight per volume" or "w/v" will mean grams per 100 cubic centimeters or milliliters.
AMENDED SHEET
F IG. 4 is a plot illustrating the organ half -life in days vs. molecular weight of various fluorocarbons in g/mol. I'he plot includes a lower molecular weight cutoff which is rela--ed to the formation of gas emboli for fluorocarbons with vapor pressures greater than 2.67 kPa (20 torr). The plot also includes an upper molecular weight cutoff which is related tlo compounds having organ retention times of less than 4 weeks.
FIG. 5 is a plot illustrating the oraan half-life in days vs. molecular weight cf various fluorocarbons in g/mol. The plot includes a lower molecular weight cutoff of 520 g/mol to take into account pulmonary gas trapping (i.e. limit to less than 1.07 kPa (8 torr)).
FIG. 6 is a graph of fluorocarbon vapor pressure in tcrr at 37 degrees celsius for various mole fractions in mix-:ures of perfiucrooctyl bromide (PFOB) and perfluorodecyl hromide (PFDB).
FIG. 7 is a table listing various properties of fluorocarbons.
Descrintion of the Preferred Embodiments I. Introduction The fluorocarbon emulsions of the present invention comprise two phases: a continuous aqueous phase and a discontinuous fluorocarbon phase. Osmotic agents and buffers, generally, are also included in the continuous phase to maintain .osmolality and pH to promote physiological acceptability.
The discontinuous phase of modern fluorocarbon emulsions for therapeutic use generally comprises from 20% w/v to up to 125% w/v of a fluorocarbon or a highly fluorinated compound (hereinafter referred as a "fluorocarbon" or a "perfluorocarbon"). As used herein, the expression "weight per volume" or "w/v" will mean grams per 100 cubic centimeters or milliliters.
AMENDED SHEET
The present invention provides a fluorocarbon emulsion which exhibits reduced pulmonary gas-trapping properties, and which has a short organ retention time.
In the first instance, in order to reduce pulmonary gas-trapping, it is desired that the fluorocarbon emulsion include a fluorocarbon, or mixture thereof, which has a vapor pressure of less than 2.67 kPa (20 torr) , and most prererably less than 1.07 kPa (B torr).
Further, in order to prevent long body retention time, iz-is desired that the single fluorocarbon be lipophilic.
Alternatively, as stated above, the emulsion may comprise a mixture of fluorocarbons in which a second fluorocarbon is added to a first, the second fiuorocarbon having a relatively higher molecular weighz~ and lower vapor pressure, and includes in its molecular structure a lipophilic moiezy. In such form, emulsions of the present invention will exhibit reduced IPRV.
II. The Compositions A. The Fluorocarbon The characteristics of fluorocarbons suitable for use in the present invention are discussed in more detail below.
Examzles of suitable fluorocarbons are provided.
1. The fluorocarbon which is to be administered in emulsion form is chosen in order to prevent or reduce pulmonary gas-trapping. It has previously been found thaz intravascular administration of fluorocarbon emulsions having vapor pressures of around 3.99 kPa (30 torr) cause gas/vapor microbubble intravascular embolism. in order to prevent this effect, it is desired that the fluorocarbon have, in the first instance, a vapor pressure of less than about 2.67 kPa (20 torr).
Referring to Figures 1 and 2, the effect of vapor pressure of the administered fluorocarbon upon pulmonary gas-trapping (PGT) is illustrated in rats and rabbits. As is clearly seen, there is an increase in PGT once the vapor pressure of the fluorocarbon exceeds approximately 1.07 kPa (S
torr). At intermediate vapor pressure levels, such as 1.60-AMENDED SHEET
ti15~9a~
In the first instance, in order to reduce pulmonary gas-trapping, it is desired that the fluorocarbon emulsion include a fluorocarbon, or mixture thereof, which has a vapor pressure of less than 2.67 kPa (20 torr) , and most prererably less than 1.07 kPa (B torr).
Further, in order to prevent long body retention time, iz-is desired that the single fluorocarbon be lipophilic.
Alternatively, as stated above, the emulsion may comprise a mixture of fluorocarbons in which a second fluorocarbon is added to a first, the second fiuorocarbon having a relatively higher molecular weighz~ and lower vapor pressure, and includes in its molecular structure a lipophilic moiezy. In such form, emulsions of the present invention will exhibit reduced IPRV.
II. The Compositions A. The Fluorocarbon The characteristics of fluorocarbons suitable for use in the present invention are discussed in more detail below.
Examzles of suitable fluorocarbons are provided.
1. The fluorocarbon which is to be administered in emulsion form is chosen in order to prevent or reduce pulmonary gas-trapping. It has previously been found thaz intravascular administration of fluorocarbon emulsions having vapor pressures of around 3.99 kPa (30 torr) cause gas/vapor microbubble intravascular embolism. in order to prevent this effect, it is desired that the fluorocarbon have, in the first instance, a vapor pressure of less than about 2.67 kPa (20 torr).
Referring to Figures 1 and 2, the effect of vapor pressure of the administered fluorocarbon upon pulmonary gas-trapping (PGT) is illustrated in rats and rabbits. As is clearly seen, there is an increase in PGT once the vapor pressure of the fluorocarbon exceeds approximately 1.07 kPa (S
torr). At intermediate vapor pressure levels, such as 1.60-AMENDED SHEET
ti15~9a~
-10- :
1.73 kPa (12-13 torr), it has been found that gas/vapcr intravascular emboli does not occur, however, a larger degree of increased pulmonary residual volume (IPRV) occurs. ?t is therefore desired that any fluorocarbon used in such a fluorocarbon emulsion have a vapor pressure of less than about 2.67 kPa (20 torr) and it is preferred that the vapor pressure be less than 2.00, 1.86, or 1.73 kPa (15, 14, or 13 torr) , and more preferedly that the vapor pressure be less than about 1. 6 0, 1.46 or 1.33 kPa (12 , 11, or 10 t orr ), and most preferedly that the vapor pressure be less than 1.20, 1.06, or .931 kPa (9, 8, or 7 torr).
As stated abeve, however, vapor pressure as rela--ed to IPRV is not the sole criteria for selecting the fluorocarbon.
In particular, it is desired that the fluorocarbon have _ short body retention time. Preferably, the half-life of the fluorocarbon in organs is less than 6 weeks, and most preferedly that the half-life is less than 3 to 4 weeks.
For single fluorocarbons, the fluorocarbon comzonent must have a low vapor pressure and be lipophilic. Possible alternatives include those listed in Table I and Figure 7, although other low vapor pressure, lipophilic fluorocarbens can be contemplated. Figures 4 and 5 illustrate the relationship _between the molecular weight of various fluorocarbons and their half life time in days.
For mixtures of fluorocarbons, the first fluorocarbon may be selected from the list below. Such fluorocarbons must have a molecular weight of less thar_ about 550 Daltons, and include bis (F-alkyl) ethenes such as C,FoCH=CHC4F, (11 F-44E" ), CF3CF9CH=CHC6F13 ("F-i36E" ), and cyclic fluorocarbons, such as C1eFla (F-decalin, perfluorodecalin or FDC) ; F-adamantane (FA) ;
perfluoroindane; F-methyladamantane (FMA); F-1,3-dimethyladamantane (FDMA); perfluoro-2,2,4,4-tetramethylpentane; F-di- or F-tri-methylbicyclo(3,3,1]nonane (nonane); C7 _12 perfluorinated amines, such as F-tripropylamine, F-4-methyloctahydroquinolizine (FMOQ), F-N-methyl-decahydroisoquinoline (FMIQ), F - n -AMENDED SHEET
~15692~
-il-methyldecahydroquinoline (FHQ), and F-N-cyclohexylpyrrolidine ( FCHP ) .
Other examples of appropriate first fluorocarbons include brominated perfluorocarbons, such as perfluorooc*_yl bromide (CBFI,Br, USAN perflubron), 1-bromopentadecafluoroheptane (C,F,SBr) , and 1-bromotridecafluorohexane (CEF33Br, also known as perfluorohexyl bromide or PFHB). Other brominated fluorocarbons are disclosed in U.S. Patent Nos. 3,975,512 and 4,987,154 to Long.
Also contemplated are first fluorocarbons having other nonfluorine substituents, such as I-chloro-heptadecafluorooctane (C8FõCl, also referred to as perfluorooctyl chloride or Pr~OC1); perfluorooctyl hydride, and similar compounds having different numbers of carbon atoms.
Additional first fluorocarbons contemplated in accordance with this invention include perfluoroalkylated ethers, halogenated ethers (especially brominated ethers), or polyethers, such as ( CF3 ) 2CFO ( CF2CF2 ) .,OCF ( CF3 ) ( CyF~ ) ,O .
Further, fluorocarbon-hydrocarbon compounds may be used, such 2 0 as, for example compounds having the general formula CnF~n_-Cn, H2n, tl ; CrF2n_,OCn, H,n, _, ; or CnF2n iCH=CHCn, H2n. 1, wherein n and n' are the same or different and are from about 1 to about 10 (so long as the compound is a liquid at room temperature). Such compounds, for example, include CBFõC2H5 and CF.;CH=CHCGH,;.
Particularly preferred fluorocarbons for use as the firsl---fluorocarbon include perfluoroamines, terminally substituted linear aliphatic perfluorocarbons having the general structure:
CF2n,1R,' wherein n is an integer from 6 to 8 and R
comprises a lipophilic moiety selected from the group of Br, Cl, I, CH3, or a saturated or unsaturated hydrocarbon of 2 or 3 carbon atoms, bis (F-alkyl) ethenes having the general structure:
C,F2ny,-CH=CH-Cn.F2n',l, wherein the sum of n and n' equals 6 to 10, and perfluoroethers having the general structure:
AMENDED SHEET
CõF2n,, - O - Cn, F2n'f1, wherein the sum of n and n' equals 6 to 9.
In addition, fluorocarbons selected from the general groups of perfluorocycloalkanes or perfluoroalkyl-cycloalkanes, perfluoroalkyl saturated'neterocyclic compounds, or perfluorotertiary amines may be suitably utilized as the first fluorocarbon. See generally Schweighart, U.S. Patent No. 4,866,096.
It will be appreciated that esters, thioethers, and other variously modified mixed fluorocarbon-hvdrocarbon compounds, including isomers, are also encompassed within the broad definition of fluorocarbon materials suitable for use as the first fluorocarbon of the present invention. Other suitable mixtures of fluorocarbons are also contemolated.
Additional fluorocarbons not listed here, but having the properties described in this disclosure that would lend themselves to therapeutic applications, are also contemplated.
Such fluorocarbons may be commercially available or specially prepared. As will be appreciated by one skilled in the art, there exist a variety of methods for the preparation of fluorocarbons that are well known in the art. See for example, Schweighart, U.S. Patent No. 4,895,876.
The second fluorocarbon is preferably an aliphatic fluorocarbon substituted with one or more lipophilic meieties and having a higher molecular weight and lower vapor pressure than the first fluorocarbon. Advantageously, the lipophilic 5 moiety is a terminal substitution on the fluorocarbon molecule. Preferably, the molecular weight of the second fluorocarbon is greater than about 540 Daltons. Constraints on the upper limit of the molecular weight of the second fluorocarbon will generally be related to its organ retention 10 time and its ability to be solubilized by the first fluorocarbon. Usually, the second fluorocarbon has a molecular weight less than about 700 Daltons.
Most preferred second fluorocarbons have boiling points greater than about 150 C and water solubilities of less than 15 about 1X10"9 moles/liter.
AMENDED SHEET
Of course, as will be appreciated by one skilled in the art, many fluorocarbons substituted with different lipophilic groups could be suitably used as the second fluorocarbon in the present invention. Such fluorocarbons may include esters, thioethers, and various fluorocarbon-hydrocarbon compounds, including isomers. Mixtures of two or more fluorocarbons satisfying the criteria set forth herein are also encompassed within the broad definition of fluorocarbon materials suitable for use as the second fluorocarbon of the present invention.
Fluorocarbons not listed here, but having the properties described in this disclosure that would lend themselves to therapeutic applications are additionally contemplated.
The lipophilic moietv is optimally selected from the group consisting of Br, Cl, I, CH3, or a saturated or unsaturated hydrocarbon of 2 or 3 carbon atoms. Consecuently, preferred second fluorocarbons may be selected from the group of terminally substituted perfluorocarbon halides as represented by the general formula:
C;F2n_:.X or C,F2nX' wherein r: is 8 or greater, preferably 10 to 12, and X is a halide selected from the group consisting of Br, Cl, or I;
1-alkyl-perfluorocarbons or dialkylperflucrocarbons as represented by the general formula:
CnF2ny,- (CH2) n,CH3 wherein n is 8 or greater, preferably 10 to 12, and n' is 0 to 2;
i-alkenyl-perfluorocarbons as represented by the general formula:
CnF2n,1-Cn,H12n,_1, , wherein n is 10 or more, preferably 10 to 12, and n' is either 2 or 3; or brominated linear or branched perfluoroethers or polyethers having the following general structure:
Br- (CnF2n,i-O-Cn,F2n-,1) , wherein n and n' are each at least 2 and the sum of n and n' is greater than or equal to E.
Most preferably, the second fluorocarbon of the present invention is selected from the group consisting of linear or branched brominated perfluorinated alkyl ethers, AMENDED SHEET
perfluorodecyl bromide (CyoF,1Br); perfluorododecyl bromide ( C,2F,SBr ) ; i -perfluorodecylethene ( C10F z,CH=CH.) ; and 1-perfluorodecylethane ( C1OF,,CH~CH3 ); with perf luorodecyl bromide particularly preferred.
In accordance with a first alternative definition, whether cr not they satisfy the foregoing definitions, fluorocarbons having critical solution temperatures (CSTs) vs hexane more than 100C below the CST of a fluorocarbon having substantially the same molecular weight (variations of up to about 10 daltons being acceptable) are also suitable for use in the present invention. A comparison between the CST and molecular weight of a number of perfluorocarbons is presented in Table I. Methodology for determining CST is presented in Example 2.
Specifically, it has been found that a mixture of F-octyl bromide and F-decvl bromide satisfies the above stated requirements. In particular, a fluorocarbon phase which includes at least 10o wt/v of F-decyl bromide is pre=erred.
Most preferably, the fluorocar'oon phase includes F-octyl bromide at about 45% to 800 or 90% wt/v, and the F-decyl bromide is nresent in the fluorocarbon phase at about 10 to 551 wt/v.
AMENDED SHEET
TABLE I
Physical Properties of Minor Components Discussed in Literature (Proposed Minor Components are listed in Boldface) Name Formula MW(g/mol) b.p.(C) CSTH(C) tõ2 (days) - ---- - -- - ----------- - ---- - ------------ - -Davis, et al. (U.S. Patent No. 4,859,363) F-perhydrofluorene Ci3F22 574 192-193 n.a. n.a.
F-perhydrophenanthrene C14F'4 624 215-216 48 n.a.
F-pe rhy d rofi u o ra nthen e C16F26 686 242-243 n.a. n.a.
Kabalnov, et al. (Kolloidin Zh. 48:27-32(1986)) F-N-methylcyclohexylpiperidine C.zFz,N 557 n.a. 40 60 Meinert (U.S. Patent No. 5,120,731); note these values are calculated, not measured.
F-N-cyclohexylmorpholine C,oF18N0 492 n.a. 31 13 F-dimorpholinoethane C,0F20N202 560 164 38 24 F-dimorpholinopropane C.,FZ2N2Oz 610 182 45 50 F-dimorpholinopentane C13F26N2O2 710 215 60 280 F-dipiperidine C.oF,sNZ 452 145-150 36 24 F-dipiperidinomethane C.,F18N2 502 165-175 42 55 F-dipiperidinoethane C.2F2ON2 552 181-186 49 124 F-dipiperidinopropane C,3F,NZ 602 195-203 56 282 F-dipiperidinobutane C14F24N2 652 231-238 72 1460 Present Invention F-decalin C,oF18 462 142 22 7 F-hexyl bromide C6F13Br 399 n.a. n.a. 2 F-octyl bromide CeFõBr 499 143 (-19)a 4 F-decyl bromide CJztBr 599 (198) (<0)a 23 F-bromopolyether CõF23O3Br 697 n. a. 32 30 a values for the critical solution temperature with hexane are estimated from extrapolations linear plots of the critical solution temperature vs. hydrocarbon chain length.
b the value of the boiling point of F-decyl bromide is estimated from Hildebrand solution theory.
AMENDED SHEET
B. The Emulsifvina Aaent The fluorocarbon emulsion also includes an emulsifying agent. As used in this specification, an emulsifying agent is any compound or composition t hat aids in the formation and maintenance of the droplets cf the discontinuous phase bv forming a layer at the interface between the discontinuous and continuous phases. The emulsifying agent may comprise a single compound or any combination of compounds, such as in the case of co-surfactants.
In the present invention, preferred emulsifying agents are selected from the group consisting of phospholipids, nonionic surfactants, fluorinatea surfactants, w'rlich can be neutral or anionic, and combinations of such emulsifying agents.
Lecithin is a phospholipid that has frequently been used as a fluorocarbon emulsifying agent, as is more fullv described in U.S. Patent No. 4,865,836. Egg yolk phospholipids have shown great promise as emulsifying agents for fluorocarbons. See e.g., Long, U.S. Patent No.
4,987,154.
Other emulsifying agents may be used with good effect, such as fluorinated surfactants, also known as fluorosurfactants. Fluorosurfaczants that can provide stable emulsions include triperfluoroalkylcholate;
perfluoroalkylcholestanol; perfluoroalkyloxymethylcholate;
C3F70(CFz)3C(=O)NH(CH2)3N(O) (CH3) 2 (XMO-10) ; and fluorinated polyhydroxylated surfactants, such as, for example, those discussed in "Design, Synthesis and Evaluation of Fluorocarboas and Surfactants for In Vivo Applications New Perfluoroalkylated Polyhydroxylated Surfactants" by J.G.
Riess, et al., Biomat. Artif. Cells Artif. Organs 16: 421-430 (1988).
The nonionic surfactants suitable for use in the present invention include polyoxyethylene-polyoxypropylene copolymers. An example of such class of compounds is Pluronic, such as Pluronic F-68. Anionic surfactants, particularly fatty acids (or their salts) having 12 to 24 AMENDED SHEET
carbon atoms, may also be used. One example of a suitable anionic surfactant is oleic acid, or its salt, sodium oleate.
It will be appreciated that choice of a particular emulsifying aaent is not central to the present inventior..
Indeed, virtually any emulsifying agent (including thcse still to be developed) capable of facilitating formation cf a fluorocarbon-in-water emulsion can form improved emulsions when used in the present invention. The optimum emulsifying agent or combination of emulsifying agents fcr a give:-.
application may be determined through empirical studies that do not reauire undue experimentat-on. Consequently, one practicing the art of the present invention shcu~-d choose the emulsifying aaent or combination of emulsifying aaents for such propert;_es as biocompatibility.
C. The Continuous Phase The continuous phase comprises an aqueous meaium.
Preferably, the medium is physiologically acceptable. For instance, a preferred emulsion will have the ability tc buffer and maintain pH, as well as provide an a~propriat=
osmolality. This typically has been achieved in the art through the inclusion in the aqueous phase of one or more conventional buffering and/or osmot--c agents, or an aaent that combines these properties.
Additionally, one may supplement the continuous phase with other agents or adjuvants for stabilizing or otherwise increasing the beneficial aspects ef the emulsion. These agents or adjuvants include: cholesterol, tocopherols, and/or mixtures or combinations thereof.
D. Preoaration of.the Emulsion Fluorocarbon emulsions according to the invention are prepared by means of conventional emulsification procedures, such as, for example, mechanical or ultrasonic emulsification of an emulsion formulation in a Manton-Gaulin mixer cr Microfluidizer (Microfluidics Corp., Newton, MA) as described in Example 1.
The single fluorocarbon, or the first and second fluorocarbons, are combined with the aqueous phase in the AMENDED SHEET
21,5fi922 -1 s-desired ratios, together with the surfactant. Usually, a pre-emulsion mixture is prepared bv simple mixing or blending of the various components. This pre-emulsion is then emulsified in the desired emulsification.apparatus.
when a composition of fluorocarbons is used, the second fluorocarbon can comprise from about 0.1o to 50% (w/w) of the total amount of fluorocarbon; in preferred embodiments, the second fluorocarbon comprises from about 0.5% to about 40%
(w/w) of the total amount of fluorocarbon, with the first flucrocarbon comprising the remainder of the tetal fluorocarbon. The combined fluorocarbon concentration in the emulsion is preferably anywhere within the range of about 20%
to about 125% (w/v). In preferred emulsions, the total perfluorocarbon concentration is from about 30%, 400, cr 50%
to about 701, 80%, 90%, or 100 0(w/v) . Emulsifiers are added in concentrations of from about 0.1% to 10%, more preferably lo or 2% to about 6% (w/v).
EXAMPLE I
Preoaration of Reference Emulsion Comnosition of Reference Emulsion: Perflubron/Lecithin ( 90 /4 o w/v) A reference emulsion containing 90 g PFOE, 4 g egg yolk phospholipid (EYP) , and physiological levels of salts and buffers was prepared by high pressure homogenization according to the method of Long (U.S. Patent No. 4,987,154).
Measurement of Critical Solution Temperature (CST) Critical solution temperature for fluorocarbon liquids was measured in the following manner: Equivolume mixtures of the test fluorocarbon and hydrocarbon (e.g., hexane) are placed in a sealed vial and submerged in a temperature controlled water bath. Samples are cooled until two distinct phases are present. At this point, the temperature is increased slowly. The lowest temperature at which the two AMENDED SHEET
~1~6922 phases are comzletely miscible (i.e., a single liquid phase) is defined as the CST.
For comparison purposes, all CST temperatures used in this patent are reported versus hexane. It is often not possible, however, to measure the CST for lipophilic fluorocar~Dons versus hexane, since the CSTs for these substances are very low. Thus, the CST for lipophilic substances is often measured in longer chain length hydrocarbons, and the value versus hexane is determined via extrapolation of linear plots of CST vs. alkane chain length.
Further, several other second fluorocarbons are considered similary acceptable. In particular, it appears that perfluorobromoethers, perfluorooctylethane (PFOE), perfluorononyl bromide, perfluorooctyl ethane, and cther compounds selected from the group of alkyl-perfluoro-alkanes (such as CeF_,C2H5 and C1oF21C2F5) either individually or in mixtures, are believed suitable.
In any case, the second fluorocarbon is chosen such that when mixed wich the first fluorocarbon in appropriate ratios, it eliminates pulmonary gas trapping (i.e. the fluorocarbon phase has a vapor pressure of less than 2.67 kPa (20 torr), and preferably less than 1.07 kPa (8 torr), and has an organ half-life of about 3 to 4 weeks. It is possible to derive acceptable compositions through calculation of the vapor pressure of the mixture of fluorocarbons with Raoult's law, as was done in Figure 6, or by determ;ining the vapor pressure empirically.
Effect of Vapor Pressure on IPRV
Figures 1 and 2 illustrate the effect of vapor pressure on IPRV in rats and rabbits respectively. It is clear that at vapor pressures less than about 1.07 kPa (8 torr) IPRV is substantially reduced. Further, as illustrated in Figure 6, mixtures of 60% w/v PFOB and 30% w/v PFDB obey Raoult's law and have a vapor pressure of about 1.07 kPa (8 torr). These mixtures are able to effectively decrease IPRV to levels AMENDED SHEET
2t56922 observed for single fluorocarbons with vapor pressures of about .013 kPa (0.1 torr).
Although the present invention has been di sclosed in the context of certain preferred embodiments, it is intended that the scope of the invention be measured by the claims that follow, and not be limited to those preferred embodiments.
AMENDED SHEET
1.73 kPa (12-13 torr), it has been found that gas/vapcr intravascular emboli does not occur, however, a larger degree of increased pulmonary residual volume (IPRV) occurs. ?t is therefore desired that any fluorocarbon used in such a fluorocarbon emulsion have a vapor pressure of less than about 2.67 kPa (20 torr) and it is preferred that the vapor pressure be less than 2.00, 1.86, or 1.73 kPa (15, 14, or 13 torr) , and more preferedly that the vapor pressure be less than about 1. 6 0, 1.46 or 1.33 kPa (12 , 11, or 10 t orr ), and most preferedly that the vapor pressure be less than 1.20, 1.06, or .931 kPa (9, 8, or 7 torr).
As stated abeve, however, vapor pressure as rela--ed to IPRV is not the sole criteria for selecting the fluorocarbon.
In particular, it is desired that the fluorocarbon have _ short body retention time. Preferably, the half-life of the fluorocarbon in organs is less than 6 weeks, and most preferedly that the half-life is less than 3 to 4 weeks.
For single fluorocarbons, the fluorocarbon comzonent must have a low vapor pressure and be lipophilic. Possible alternatives include those listed in Table I and Figure 7, although other low vapor pressure, lipophilic fluorocarbens can be contemplated. Figures 4 and 5 illustrate the relationship _between the molecular weight of various fluorocarbons and their half life time in days.
For mixtures of fluorocarbons, the first fluorocarbon may be selected from the list below. Such fluorocarbons must have a molecular weight of less thar_ about 550 Daltons, and include bis (F-alkyl) ethenes such as C,FoCH=CHC4F, (11 F-44E" ), CF3CF9CH=CHC6F13 ("F-i36E" ), and cyclic fluorocarbons, such as C1eFla (F-decalin, perfluorodecalin or FDC) ; F-adamantane (FA) ;
perfluoroindane; F-methyladamantane (FMA); F-1,3-dimethyladamantane (FDMA); perfluoro-2,2,4,4-tetramethylpentane; F-di- or F-tri-methylbicyclo(3,3,1]nonane (nonane); C7 _12 perfluorinated amines, such as F-tripropylamine, F-4-methyloctahydroquinolizine (FMOQ), F-N-methyl-decahydroisoquinoline (FMIQ), F - n -AMENDED SHEET
~15692~
-il-methyldecahydroquinoline (FHQ), and F-N-cyclohexylpyrrolidine ( FCHP ) .
Other examples of appropriate first fluorocarbons include brominated perfluorocarbons, such as perfluorooc*_yl bromide (CBFI,Br, USAN perflubron), 1-bromopentadecafluoroheptane (C,F,SBr) , and 1-bromotridecafluorohexane (CEF33Br, also known as perfluorohexyl bromide or PFHB). Other brominated fluorocarbons are disclosed in U.S. Patent Nos. 3,975,512 and 4,987,154 to Long.
Also contemplated are first fluorocarbons having other nonfluorine substituents, such as I-chloro-heptadecafluorooctane (C8FõCl, also referred to as perfluorooctyl chloride or Pr~OC1); perfluorooctyl hydride, and similar compounds having different numbers of carbon atoms.
Additional first fluorocarbons contemplated in accordance with this invention include perfluoroalkylated ethers, halogenated ethers (especially brominated ethers), or polyethers, such as ( CF3 ) 2CFO ( CF2CF2 ) .,OCF ( CF3 ) ( CyF~ ) ,O .
Further, fluorocarbon-hydrocarbon compounds may be used, such 2 0 as, for example compounds having the general formula CnF~n_-Cn, H2n, tl ; CrF2n_,OCn, H,n, _, ; or CnF2n iCH=CHCn, H2n. 1, wherein n and n' are the same or different and are from about 1 to about 10 (so long as the compound is a liquid at room temperature). Such compounds, for example, include CBFõC2H5 and CF.;CH=CHCGH,;.
Particularly preferred fluorocarbons for use as the firsl---fluorocarbon include perfluoroamines, terminally substituted linear aliphatic perfluorocarbons having the general structure:
CF2n,1R,' wherein n is an integer from 6 to 8 and R
comprises a lipophilic moiety selected from the group of Br, Cl, I, CH3, or a saturated or unsaturated hydrocarbon of 2 or 3 carbon atoms, bis (F-alkyl) ethenes having the general structure:
C,F2ny,-CH=CH-Cn.F2n',l, wherein the sum of n and n' equals 6 to 10, and perfluoroethers having the general structure:
AMENDED SHEET
CõF2n,, - O - Cn, F2n'f1, wherein the sum of n and n' equals 6 to 9.
In addition, fluorocarbons selected from the general groups of perfluorocycloalkanes or perfluoroalkyl-cycloalkanes, perfluoroalkyl saturated'neterocyclic compounds, or perfluorotertiary amines may be suitably utilized as the first fluorocarbon. See generally Schweighart, U.S. Patent No. 4,866,096.
It will be appreciated that esters, thioethers, and other variously modified mixed fluorocarbon-hvdrocarbon compounds, including isomers, are also encompassed within the broad definition of fluorocarbon materials suitable for use as the first fluorocarbon of the present invention. Other suitable mixtures of fluorocarbons are also contemolated.
Additional fluorocarbons not listed here, but having the properties described in this disclosure that would lend themselves to therapeutic applications, are also contemplated.
Such fluorocarbons may be commercially available or specially prepared. As will be appreciated by one skilled in the art, there exist a variety of methods for the preparation of fluorocarbons that are well known in the art. See for example, Schweighart, U.S. Patent No. 4,895,876.
The second fluorocarbon is preferably an aliphatic fluorocarbon substituted with one or more lipophilic meieties and having a higher molecular weight and lower vapor pressure than the first fluorocarbon. Advantageously, the lipophilic 5 moiety is a terminal substitution on the fluorocarbon molecule. Preferably, the molecular weight of the second fluorocarbon is greater than about 540 Daltons. Constraints on the upper limit of the molecular weight of the second fluorocarbon will generally be related to its organ retention 10 time and its ability to be solubilized by the first fluorocarbon. Usually, the second fluorocarbon has a molecular weight less than about 700 Daltons.
Most preferred second fluorocarbons have boiling points greater than about 150 C and water solubilities of less than 15 about 1X10"9 moles/liter.
AMENDED SHEET
Of course, as will be appreciated by one skilled in the art, many fluorocarbons substituted with different lipophilic groups could be suitably used as the second fluorocarbon in the present invention. Such fluorocarbons may include esters, thioethers, and various fluorocarbon-hydrocarbon compounds, including isomers. Mixtures of two or more fluorocarbons satisfying the criteria set forth herein are also encompassed within the broad definition of fluorocarbon materials suitable for use as the second fluorocarbon of the present invention.
Fluorocarbons not listed here, but having the properties described in this disclosure that would lend themselves to therapeutic applications are additionally contemplated.
The lipophilic moietv is optimally selected from the group consisting of Br, Cl, I, CH3, or a saturated or unsaturated hydrocarbon of 2 or 3 carbon atoms. Consecuently, preferred second fluorocarbons may be selected from the group of terminally substituted perfluorocarbon halides as represented by the general formula:
C;F2n_:.X or C,F2nX' wherein r: is 8 or greater, preferably 10 to 12, and X is a halide selected from the group consisting of Br, Cl, or I;
1-alkyl-perfluorocarbons or dialkylperflucrocarbons as represented by the general formula:
CnF2ny,- (CH2) n,CH3 wherein n is 8 or greater, preferably 10 to 12, and n' is 0 to 2;
i-alkenyl-perfluorocarbons as represented by the general formula:
CnF2n,1-Cn,H12n,_1, , wherein n is 10 or more, preferably 10 to 12, and n' is either 2 or 3; or brominated linear or branched perfluoroethers or polyethers having the following general structure:
Br- (CnF2n,i-O-Cn,F2n-,1) , wherein n and n' are each at least 2 and the sum of n and n' is greater than or equal to E.
Most preferably, the second fluorocarbon of the present invention is selected from the group consisting of linear or branched brominated perfluorinated alkyl ethers, AMENDED SHEET
perfluorodecyl bromide (CyoF,1Br); perfluorododecyl bromide ( C,2F,SBr ) ; i -perfluorodecylethene ( C10F z,CH=CH.) ; and 1-perfluorodecylethane ( C1OF,,CH~CH3 ); with perf luorodecyl bromide particularly preferred.
In accordance with a first alternative definition, whether cr not they satisfy the foregoing definitions, fluorocarbons having critical solution temperatures (CSTs) vs hexane more than 100C below the CST of a fluorocarbon having substantially the same molecular weight (variations of up to about 10 daltons being acceptable) are also suitable for use in the present invention. A comparison between the CST and molecular weight of a number of perfluorocarbons is presented in Table I. Methodology for determining CST is presented in Example 2.
Specifically, it has been found that a mixture of F-octyl bromide and F-decvl bromide satisfies the above stated requirements. In particular, a fluorocarbon phase which includes at least 10o wt/v of F-decyl bromide is pre=erred.
Most preferably, the fluorocar'oon phase includes F-octyl bromide at about 45% to 800 or 90% wt/v, and the F-decyl bromide is nresent in the fluorocarbon phase at about 10 to 551 wt/v.
AMENDED SHEET
TABLE I
Physical Properties of Minor Components Discussed in Literature (Proposed Minor Components are listed in Boldface) Name Formula MW(g/mol) b.p.(C) CSTH(C) tõ2 (days) - ---- - -- - ----------- - ---- - ------------ - -Davis, et al. (U.S. Patent No. 4,859,363) F-perhydrofluorene Ci3F22 574 192-193 n.a. n.a.
F-perhydrophenanthrene C14F'4 624 215-216 48 n.a.
F-pe rhy d rofi u o ra nthen e C16F26 686 242-243 n.a. n.a.
Kabalnov, et al. (Kolloidin Zh. 48:27-32(1986)) F-N-methylcyclohexylpiperidine C.zFz,N 557 n.a. 40 60 Meinert (U.S. Patent No. 5,120,731); note these values are calculated, not measured.
F-N-cyclohexylmorpholine C,oF18N0 492 n.a. 31 13 F-dimorpholinoethane C,0F20N202 560 164 38 24 F-dimorpholinopropane C.,FZ2N2Oz 610 182 45 50 F-dimorpholinopentane C13F26N2O2 710 215 60 280 F-dipiperidine C.oF,sNZ 452 145-150 36 24 F-dipiperidinomethane C.,F18N2 502 165-175 42 55 F-dipiperidinoethane C.2F2ON2 552 181-186 49 124 F-dipiperidinopropane C,3F,NZ 602 195-203 56 282 F-dipiperidinobutane C14F24N2 652 231-238 72 1460 Present Invention F-decalin C,oF18 462 142 22 7 F-hexyl bromide C6F13Br 399 n.a. n.a. 2 F-octyl bromide CeFõBr 499 143 (-19)a 4 F-decyl bromide CJztBr 599 (198) (<0)a 23 F-bromopolyether CõF23O3Br 697 n. a. 32 30 a values for the critical solution temperature with hexane are estimated from extrapolations linear plots of the critical solution temperature vs. hydrocarbon chain length.
b the value of the boiling point of F-decyl bromide is estimated from Hildebrand solution theory.
AMENDED SHEET
B. The Emulsifvina Aaent The fluorocarbon emulsion also includes an emulsifying agent. As used in this specification, an emulsifying agent is any compound or composition t hat aids in the formation and maintenance of the droplets cf the discontinuous phase bv forming a layer at the interface between the discontinuous and continuous phases. The emulsifying agent may comprise a single compound or any combination of compounds, such as in the case of co-surfactants.
In the present invention, preferred emulsifying agents are selected from the group consisting of phospholipids, nonionic surfactants, fluorinatea surfactants, w'rlich can be neutral or anionic, and combinations of such emulsifying agents.
Lecithin is a phospholipid that has frequently been used as a fluorocarbon emulsifying agent, as is more fullv described in U.S. Patent No. 4,865,836. Egg yolk phospholipids have shown great promise as emulsifying agents for fluorocarbons. See e.g., Long, U.S. Patent No.
4,987,154.
Other emulsifying agents may be used with good effect, such as fluorinated surfactants, also known as fluorosurfactants. Fluorosurfaczants that can provide stable emulsions include triperfluoroalkylcholate;
perfluoroalkylcholestanol; perfluoroalkyloxymethylcholate;
C3F70(CFz)3C(=O)NH(CH2)3N(O) (CH3) 2 (XMO-10) ; and fluorinated polyhydroxylated surfactants, such as, for example, those discussed in "Design, Synthesis and Evaluation of Fluorocarboas and Surfactants for In Vivo Applications New Perfluoroalkylated Polyhydroxylated Surfactants" by J.G.
Riess, et al., Biomat. Artif. Cells Artif. Organs 16: 421-430 (1988).
The nonionic surfactants suitable for use in the present invention include polyoxyethylene-polyoxypropylene copolymers. An example of such class of compounds is Pluronic, such as Pluronic F-68. Anionic surfactants, particularly fatty acids (or their salts) having 12 to 24 AMENDED SHEET
carbon atoms, may also be used. One example of a suitable anionic surfactant is oleic acid, or its salt, sodium oleate.
It will be appreciated that choice of a particular emulsifying aaent is not central to the present inventior..
Indeed, virtually any emulsifying agent (including thcse still to be developed) capable of facilitating formation cf a fluorocarbon-in-water emulsion can form improved emulsions when used in the present invention. The optimum emulsifying agent or combination of emulsifying agents fcr a give:-.
application may be determined through empirical studies that do not reauire undue experimentat-on. Consequently, one practicing the art of the present invention shcu~-d choose the emulsifying aaent or combination of emulsifying aaents for such propert;_es as biocompatibility.
C. The Continuous Phase The continuous phase comprises an aqueous meaium.
Preferably, the medium is physiologically acceptable. For instance, a preferred emulsion will have the ability tc buffer and maintain pH, as well as provide an a~propriat=
osmolality. This typically has been achieved in the art through the inclusion in the aqueous phase of one or more conventional buffering and/or osmot--c agents, or an aaent that combines these properties.
Additionally, one may supplement the continuous phase with other agents or adjuvants for stabilizing or otherwise increasing the beneficial aspects ef the emulsion. These agents or adjuvants include: cholesterol, tocopherols, and/or mixtures or combinations thereof.
D. Preoaration of.the Emulsion Fluorocarbon emulsions according to the invention are prepared by means of conventional emulsification procedures, such as, for example, mechanical or ultrasonic emulsification of an emulsion formulation in a Manton-Gaulin mixer cr Microfluidizer (Microfluidics Corp., Newton, MA) as described in Example 1.
The single fluorocarbon, or the first and second fluorocarbons, are combined with the aqueous phase in the AMENDED SHEET
21,5fi922 -1 s-desired ratios, together with the surfactant. Usually, a pre-emulsion mixture is prepared bv simple mixing or blending of the various components. This pre-emulsion is then emulsified in the desired emulsification.apparatus.
when a composition of fluorocarbons is used, the second fluorocarbon can comprise from about 0.1o to 50% (w/w) of the total amount of fluorocarbon; in preferred embodiments, the second fluorocarbon comprises from about 0.5% to about 40%
(w/w) of the total amount of fluorocarbon, with the first flucrocarbon comprising the remainder of the tetal fluorocarbon. The combined fluorocarbon concentration in the emulsion is preferably anywhere within the range of about 20%
to about 125% (w/v). In preferred emulsions, the total perfluorocarbon concentration is from about 30%, 400, cr 50%
to about 701, 80%, 90%, or 100 0(w/v) . Emulsifiers are added in concentrations of from about 0.1% to 10%, more preferably lo or 2% to about 6% (w/v).
EXAMPLE I
Preoaration of Reference Emulsion Comnosition of Reference Emulsion: Perflubron/Lecithin ( 90 /4 o w/v) A reference emulsion containing 90 g PFOE, 4 g egg yolk phospholipid (EYP) , and physiological levels of salts and buffers was prepared by high pressure homogenization according to the method of Long (U.S. Patent No. 4,987,154).
Measurement of Critical Solution Temperature (CST) Critical solution temperature for fluorocarbon liquids was measured in the following manner: Equivolume mixtures of the test fluorocarbon and hydrocarbon (e.g., hexane) are placed in a sealed vial and submerged in a temperature controlled water bath. Samples are cooled until two distinct phases are present. At this point, the temperature is increased slowly. The lowest temperature at which the two AMENDED SHEET
~1~6922 phases are comzletely miscible (i.e., a single liquid phase) is defined as the CST.
For comparison purposes, all CST temperatures used in this patent are reported versus hexane. It is often not possible, however, to measure the CST for lipophilic fluorocar~Dons versus hexane, since the CSTs for these substances are very low. Thus, the CST for lipophilic substances is often measured in longer chain length hydrocarbons, and the value versus hexane is determined via extrapolation of linear plots of CST vs. alkane chain length.
Further, several other second fluorocarbons are considered similary acceptable. In particular, it appears that perfluorobromoethers, perfluorooctylethane (PFOE), perfluorononyl bromide, perfluorooctyl ethane, and cther compounds selected from the group of alkyl-perfluoro-alkanes (such as CeF_,C2H5 and C1oF21C2F5) either individually or in mixtures, are believed suitable.
In any case, the second fluorocarbon is chosen such that when mixed wich the first fluorocarbon in appropriate ratios, it eliminates pulmonary gas trapping (i.e. the fluorocarbon phase has a vapor pressure of less than 2.67 kPa (20 torr), and preferably less than 1.07 kPa (8 torr), and has an organ half-life of about 3 to 4 weeks. It is possible to derive acceptable compositions through calculation of the vapor pressure of the mixture of fluorocarbons with Raoult's law, as was done in Figure 6, or by determ;ining the vapor pressure empirically.
Effect of Vapor Pressure on IPRV
Figures 1 and 2 illustrate the effect of vapor pressure on IPRV in rats and rabbits respectively. It is clear that at vapor pressures less than about 1.07 kPa (8 torr) IPRV is substantially reduced. Further, as illustrated in Figure 6, mixtures of 60% w/v PFOB and 30% w/v PFDB obey Raoult's law and have a vapor pressure of about 1.07 kPa (8 torr). These mixtures are able to effectively decrease IPRV to levels AMENDED SHEET
2t56922 observed for single fluorocarbons with vapor pressures of about .013 kPa (0.1 torr).
Although the present invention has been di sclosed in the context of certain preferred embodiments, it is intended that the scope of the invention be measured by the claims that follow, and not be limited to those preferred embodiments.
AMENDED SHEET
Claims (21)
1. A fluorocarbon emulsion exhibiting reduced pulmonary gas-trapping properties, comprising:
an aqueous phase;
an emulsifying agent; and a liquid fluorocarbon phase having a vapor pressure of less than about 2.67 kPa (20 torr) at 37°C, having an organ half-life of less than about 6 weeks, and having a lipophilic component, said fluorocarbon phase comprising a mixture of at least two fluorocarbons in a weight ratio of from about 20:1 to about 1:20.
an aqueous phase;
an emulsifying agent; and a liquid fluorocarbon phase having a vapor pressure of less than about 2.67 kPa (20 torr) at 37°C, having an organ half-life of less than about 6 weeks, and having a lipophilic component, said fluorocarbon phase comprising a mixture of at least two fluorocarbons in a weight ratio of from about 20:1 to about 1:20.
2. The fluorocarbon emulsion of Claim 1, wherein said fluorocarbon phase comprises a first fluorocarbon having an organ half-life of less than about 4 weeks, and a second fluorocarbon having a vapor pressure less than said first fluorocarbon.
3. The fluorocarbon emulsion of Claim 2, wherein said first fluorocarbon has a molecular weight of about 460 to 550 Daltons, and said second fluorocarbon has a molecular weight of about 560 to 700 Daltons.
4. The fluorocarbon emulsion of Claim 1, wherein said fluorocarbon phase has a vapor pressure at 37°C of less than about 1.33 kPa (10 torr).
5. The fluorocarbon emulsion of Claim 1, wherein said fluorocarbon phase has a vapor pressure at 37°C of less than 1.07 kPa (8 torr).
6. A fluorocarbon emulsion exhibiting reduced pulmonary gas-trapping properties, comprising:
an aqueous phase;
an emulsifier; and a fluorocarbon phase including at least 10% weight by volume of F-decyl bromide.
an aqueous phase;
an emulsifier; and a fluorocarbon phase including at least 10% weight by volume of F-decyl bromide.
7. The fluorocarbon emulsion of Claim 6, wherein said fluorocarbon phase additionally comprises F-octyl bromide.
8. The fluorocarbon emulsion of Claim 7, wherein said perfluorooctyl bromide is present in said fluorocarbon phase at about 45% to 90% weight per volume, and said F-decyl bromide is present in said fluorocarbon phase at about 10% to 55% weight per volume.
9. A fluorocarbon emulsion exhibiting reduced pulmonary gas trapping, comprising:
an aqueous phase;
an emulsifier; and a fluorocarbon phase consisting essentially of a single low vapor pressure; fluorocarbon phase having an organ half-life of less than about 6 weeks, and a vapor pressure at 37°C of less than 1.33 kPa (10 torr).
an aqueous phase;
an emulsifier; and a fluorocarbon phase consisting essentially of a single low vapor pressure; fluorocarbon phase having an organ half-life of less than about 6 weeks, and a vapor pressure at 37°C of less than 1.33 kPa (10 torr).
10. The fluorocarbon emulsion of Claim 9, wherein said fluorocarbon is F-octyl ethane or F-decyl ethane.
11. The fluorocarbon emulsion of Claim 9, wherein said fluorocarbon has an organ half-life of less than 3 to 4 weeks.
12. The fluorocarbon emulsion of Claim 9, wherein said fluorocarbon has a vapor pressure at 37°C of less than 1.07 kPa (8 torr).
13. In a method of preparing a fluorocarbon emulsion for intravenous administration to a patient, by forming an emulsion of an aqueous phase, an emulsifier, and a first fluorocarbon in a fluorocarbon phase wherein the vapor pressure of the fluorocarbon phase is greater than about 1.07 kPa (8 torr) at 37°C, the improvement comprising:
reducing the pulmonary gas trapping effect of the emulsion upon intravenous administration by providing in combination with the first fluorocarbon in the fluorocarbon phase an effective amount of a second fluorocarbon, wherein the addition of the second fluorocarbon reduces the vapor pressure of the fluorocarbon phase at 37°C to less than about 1.07 kPa (8 torr), wherein the fluorocarbon phase has a melting point less than about 37°C and an organ retention half-life less than about 4 weeks.
reducing the pulmonary gas trapping effect of the emulsion upon intravenous administration by providing in combination with the first fluorocarbon in the fluorocarbon phase an effective amount of a second fluorocarbon, wherein the addition of the second fluorocarbon reduces the vapor pressure of the fluorocarbon phase at 37°C to less than about 1.07 kPa (8 torr), wherein the fluorocarbon phase has a melting point less than about 37°C and an organ retention half-life less than about 4 weeks.
14. The method of Claim 13, wherein said second fluorocarbon includes a lipophilic moiety.
15. The method of Claim 13, wherein said second fluorocarbon is a bromofluorocarbon.
16. Use of a first fluorocarbon in combination with an effective amount of a second fluorocarbon to reduce the pulmonary gas trapping effect of a fluorocarbon emulsion in a mammal, wherein the emulsion comprises an aqueous phase, an emulsifier, the first fluorocarbon in a fluorocarbon phase wherein the vapour pressure of the fluorocarbon phase is greater than about 1.07 kPa (8 torr) at 37°C, and the effective amount of the second fluorocarbon wherein the second fluorocarbon reduces the vapour pressure of the fluorocarbon phase at 37°C to less than about 1.07 kPa (8 torr), wherein the fluorocarbon phase has a melting point less than about 37°C and an organ retention half-life less than about 4 weeks.
17. A medicament for use in reducing the pulmonary gas trapping effect of a fluorocarbon emulsion comprising an aqueous phase, an emulsifier, and a first fluorocarbon in a fluorocarbon phase, wherein the vapor pressure of said fluorocarbon phase is greater than about 1.07 kPa (8 torr) at 37°C, the improvement comprising:
an effective amount of a second fluorocarbon in combination with said first fluorocarbon, wherein the second fluorocarbon reduces the vapor pressure of the fluorocarbon phase at 37°C to less than about 1.07 kPa (8 torr), wherein the fluorocarbon phase has a melting point less than about 37°C and an organ retention half-life less than about 4 weeks.
an effective amount of a second fluorocarbon in combination with said first fluorocarbon, wherein the second fluorocarbon reduces the vapor pressure of the fluorocarbon phase at 37°C to less than about 1.07 kPa (8 torr), wherein the fluorocarbon phase has a melting point less than about 37°C and an organ retention half-life less than about 4 weeks.
18. The medicament of Claim 17, wherein said fluorocarbon is F-octyl ethane or F-decyl ethane.
19. The medicament of Claim 17, wherein said first fluorocarbon has a molecular weight of about 460 to 550 Daltons, and said second fluorocarbon has a molecular weight of about 560 to 700 daltons.
20. The medicament of Claim 17, wherein said second fluorocarbon includes a lipophilic moiety.
21. The medicament of Claim 17, wherein said second fluorocarbon is a bromofluorocarbon.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US08/032,333 | 1993-03-16 | ||
| US08/032,333 US5635538A (en) | 1993-03-16 | 1993-03-16 | Fluorocarbon emulsions with reduced pulmonary gas-trapping properties |
| PCT/US1994/002222 WO1994021227A1 (en) | 1993-03-16 | 1994-03-01 | Fluorocarbon emulsions with reduced pulmonary gas-trapping properties |
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| CA2156922A1 CA2156922A1 (en) | 1994-09-29 |
| CA2156922C true CA2156922C (en) | 2007-05-22 |
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| CA002156922A Expired - Fee Related CA2156922C (en) | 1993-03-16 | 1994-03-01 | Fluorocarbon emulsions with reduced pulmonary gas-trapping properties |
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