Thermally reversible water in oil in water emulsions
A thermally reversible water in oil in water (W/O/W) emulsion including a thermally reversible viscosifying polymer in the continuous aqueous phase of the emulsion. The thermally reversible viscosifying polymer of the W/O/W emulsion includes a block copolymer having at least a first polyoxyalkylene block having a hydrophobic region and a hydrophilic region effective to form micelles in solution in response to a change in temperature, and at least a second block comprising a poly(vinylcarboxylic acid).
1. A thermally reversible water in oil in water (W/O/W) emulsion having a continuous aqueous phase comprising a thermally reversible viscosifying polymer, the thermally reversible polymer comprising 0.01 to 20 wt % of the continuous aqueous phase, wherein the viscosity of the emulsion increases about 2-fold to about 100-fold in response to an increase in temperature.
2. A thermally reversible water in oil in water (W/O/W) emulsion having a continuous aqueous phase comprising a thermally reversible viscosifying polymer, wherein the thermally reversible viscosifying polymer comprises a block copolymer comprising at least a first polyoxyalkylene block having a hydrophobic region and a hydrophilic region effective to form micelles in solution in response to a change in temperature, and at least a second block comprising a poly(vinylcarboxylic acid).
3. The W/O/W emulsion of claim 2 , wherein the block copolymer is a linear block copolymer.
4. The W/O/W emulsion of claim 2 , wherein the block copolymer is a random block copolymer.
5. The composition of claim 2 , wherein said polyoxyalkylene comprises polyoxyethylene as the hydrophilic region and polyoxypropylene as the hydrophobic region.
6. The composition of claim 2 , wherein the poly-(vinylcarboxylic acid) is selected from the group consisting of acrylic acid, substituted acrylic acids, methacrylic acid, substituted methacrylic acids, and ionized forms thereof.
7. The composition of claim 2 , wherein the polyoxyalkylene comprises a triblock polymer of polyoxyethylene (POE) and polyoxypropylene (POP) having the formula (POE) a (POP) b (POE) a , where a is in the range of 100-50, and b is in the range of 50-70.
8. The composition of claim 1 , wherein the viscosity increase occurs at a temperature in the range of about 20 to 40° C.
9. The composition of claim 2 , wherein the thermally reversible viscosifying polymer comprises about 0.01 to 20 wt % of the continuous aqueous phase.
10. The composition of claim 2 , wherein the thermally reversible viscosifying polymer comprises about 0.1 to 10 wt % of the continuous aqueous phase.
11. The composition of claim 2 , wherein the thermally reversible viscosifying polymer comprises about 0.01 to 1 wt % of the continuous aqueous phase.
12. The emulsion of claim 1 , wherein active agents are entrapped within a discontinuous water phase of the W/O/W emulsion.
13. The emulsion of claim 1 , wherein active agents are entrapped within oil phase droplets of the W/O/W emulsion.
14. A pharmaceutical composition, comprising:
a water in oil in water emulsion having a continuous aqueous phase, wherein the continuous aqueous phase comprises a thermally reversible viscosifying polymer, the thermally reversible viscosifying polymer comprising 0.01 to 20 wt % of the continuous aqueous phase, wherein the viscosity of the emulsion increases about 2-fold to about 100-fold in response to an increase in temperature; and
at least one active agent in the oil or water discontinuous phase.
15. The pharmaceutical composition of claim 14 , wherein the thermally reversible viscosifying polymer comprises a block copolymer comprising at least a first polyoxyalkylene block having a hydrophobic region and a hydrophilic region effective to form micelles in solution in response to a change in temperature, and at least a second block comprising a poly(vinylcarboxylic acid).
16. The pharmaceutical composition of claim 14 , wherein said polyoxyalkylene comprises polyoxyethylene as the hydrophilic region and polyoxypropylene as the hydrophobic region.
17. The pharmaceutical composition of claim 16 , wherein the poly(vinylcarboxylic acid) is selected from the group consisting of acrylic acid, substituted acrylic acids, methacrylic acid, substituted methacrylic acids, and ionized forms thereof.
18. The pharmaceutical composition of claim 14 , wherein the polyoxyalkylene comprises a triblock polymer of polyoxyethylene (POE) and polyoxypropylene (POP) having the formula (POE) a (POP) b (POE) a , where a is in the range of 100-50, and b is in the range of 50-70.
19. The pharmaceutical composition of claim 14 , wherein the viscosity increase occurs at a temperature in the range of about 20 to 40° C.
20. The pharmaceutical composition of claim 14 , wherein the thermally reversible viscosifying polymer comprises about 0.01 to 10 wt % of the continuous aqueous phase.
21. The pharmaceutical composition of claim 14 , wherein the thermally reversible viscosifying polymer comprises about 0.01 to 1 wt % of the continuous aqueous phase.
22. The pharmaceutical composition of claim 14 , wherein active agents are entrapped within the discontinuous water phase of the W/O/W emulsion.
23. The pharmaceutical composition of claim 14 , wherein active agents are entrapped within oil phase droplets of the W/O/W emulsion.
24. The composition of claim 2 , wherein the viscosity of the emulsion increases at a temperature in the range of about 20 to 40° C.
25. The composition of claim 1 , wherein the thermally reversible viscosifying polymer comprises about 0.1 to 10 wt % of the continuous aqueous phase.
26. The composition of claim 1 , wherein the thermally reversible viscosifying polymer comprises about 0.01 to 1 wt % of the continuous aqueous phase.
27. The emulsion of claim 2 , wherein active agents are entrapped within the discontinuous water phase of the W/O/W emulsion.
28. The emulsion of claim 2 , wherein active agents are entrapped within oil phase droplets of the W/O/W emulsion.