1. A filter assembly for obtaining a sample of filtrate from a contaminated fluid, the assembly comprising
a filter element comprising an elongate porous tube having an exterior surface wherein a portion of the exterior surface is arranged to be immersed in a fluid to be filtered and wherein the tube is substantially rigid so that, in use, the interior bore is maintained as a passage for the filtered fluid; and
a pump, having an inlet and coupled to the interior bore of the filter element and an outlet, for drawing filtrate through the filter element from the exterior surface of the filter element to the interior bore and through the interior bore to the inlet of the pump;
means for incrementally extending a further portion of the exterior surface of the filter element to immerse the further portion in the contaminated fluid as the filter element becomes clogged.
2. Apparatus according to claim 1 wherein a single drive means is arranged to operate the pump to draw fluid through the filter element and to advance the filter element to expose further portions of the surface.
3. Apparatus according to claim 1 wherein the assembly includes coupling means arranged to couple a rotary drive to the pump to draw fluid through the filter element when rotation is applied in a first direction and to advance the filter element when rotation is applied in the opposite direction.
4. Apparatus according to claim 1 wherein the pump is arranged to pump fluid back through the filter element from the interior surface of the filter element to the exterior surface of the filter element to effect back-flushing of the filter element.
5. Apparatus according to claim 1 wherein the filter assembly is removably coupled to a drive means so that the filter assembly may be renewed without having to renew the drive means.
6. Apparatus according to claim 1 wherein the filter element comprises a substantially cylindrical tube.
7. Apparatus according to claim 1 wherein the further portion of the exterior surface of the filter element is incrementally exposed by means of a relatively rotatable threaded shaft or screw and nut member, one of the screw or shaft being arranged to be rotated by drive means.
8. A filter assembly for obtaining a sample of filtrate from a contaminated fluid, the assembly comprising:
a filter element comprising an elongate porous tube having an exterior surface wherein a portion of the exterior surface is arranged to be exposed to a fluid to be filter; and
means for incrementally exposing a further portion of the exterior surface of the filter element to the contaminated fluid as the filter element becomes clogged;
the interior bore of the tube being arranged to couple to an inlet of a pump for drawing filtrate through the filter element from the exterior surface of the filter element to the interior bore of the filter element;
a single drive means being arranged to operate the pump to draw fluid through the filter element and to advance the filter element to expose further portions of the surface; and
the filter assembly further including coupling means arranged to couple a rotary drive to the pump to draw fluid through the filter element when rotation is applied in a first direction and to advance the filter element when rotation is applied in the opposite direction.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
What is claimed is:
1. A diblock copolymer comprising a hydrophilic block and a hydrophobic block, said hydrophilic block comprising a polyethylene oxide polymer, said hydrophobic block comprising a polycaprolactone polymer, said polycaprolactone polymer comprising a number of caprolactone monomers selected from 5 to 150, said polyethylene oxide polymer comprising a number of ethylene oxide monomers selected from 20 to 100, wherein said diblock copolymers are assembled in a suitable aqueous medium such that said hydrophobic blocks define a core of said micellar system and said hydrophilic blocks define a shell surrounding said core.
2. The diblock copolymer micellar system according to claim 1, wherein said number of caprolactone monomers is 20 and said number of ethylene oxide monomers is 44; wherein said diblock copolymers are assembled in a suitable aqueous medium such that said hydrophobic blocks define a core of said micellar system and said hydrophilic blocks define a shell surrounding said core.
3. A diblock copolymer comprising a hydrophilic block and a hydrophobic block, said hydrophilic block comprising a polyethylene oxide polymer, said hydrophobic block comprising a polycaprolactone polymer, said polycaprolactone polymer comprising 20 caprolactone monomers, said polyethylene oxide polymer comprising 44 ethylene oxide monomers, wherein said diblock copolymers are assembled in a suitable aqueous medium such that said hydrophobic blocks define a core of said micellar system and said hydrophilic blocks define a shell surrounding said core.
4. A diblock copolymer micellar system according to claim 1, wherein said micellar system has a diameter varying essentially from about 10 nanometers to about 100 nanometers.
5. A diblock copolymer micellar system according to claim 2, wherein said micellar system has a diameter varying essentially from about 10 nanometers to about 100 nanometers.
6. A diblock copolymer micellar system according to anyone of claim 2, wherein said micellar system contains a biologically active agent into said core.
7. A diblock copolymer micellar system according to claim 3, wherein said biologically active agent is lipophilic.
8. A diblock copolymer micellar system according to claim 4, wherein said biologically active agent comprises a neuroactive agent.
9. A diblock copolymer micellar system according to claim 5, wherein said neuroactive agent is a neurotrophic agent selected from the group consisting of FK506 and L-685,818.
10. A diblock copolymer micellar system according to claim 6, wherein said neuroactive agent consists of L-685,818.
11. A composition comprising a population of micellar systems according to claim 3 in combination with a suitable pharmaceutical carrier.
12. A composition comprising a population of micellar systems according to claim 7 in combination with a suitable pharmaceutical carrier.
13. A composition according to claim 7, wherein said copolymers are present in a solution in an amount of about 1 percent by weight.
14. A delivery system for delivering a biologically active agent in situ in a patient, the delivery system comprising a population of micellar systems according to claim 1.
15. A delivery system according to claim 11, wherein said in situ delivery is to the central nervous system of said patient.
16. A method for preparing a population of micellar systems according to claim 1 which comprises the steps of:
a) dissolving said copolymers in a suitable organic solvant solution; and
b) adding water in a dropwise fashion to said solution to form said micellar systems.