Microencapsulation of bacteriophages and related products
An encapsulated bacteriophage formulation and a method for encapsulating bacteriophages and bacteriophage-related products in polymeric microcapsules is provided. Some embodiments of the method of producing the encapsulated bacteriophages involves a water-in-oil-in-water double emulsion.
1 . A composition comprising:
polymer microcapsules; and
active bacteriophages encapsulated in the polymer microcapsules;
wherein the polymer microcapsules include an amino-acid based polymer and the active bacteriophages are dispersed in the polymer microcapsules;
wherein the amino-acid based polymer includes a polymer matrix defining a hollow structure in which a first aqueous suspension is encapsulated in at least some of the polymer microcapsules, at least some of the active bacteriophages being suspended in the first aqueous suspension outside of the polymer matrix.
2 . The composition as defined in claim 1 , wherein at least some of the active bacteriophages are dispersed in the amino-acid based polymer.
3 . The composition as defined in claim 1 , wherein the first aqueous suspension includes polyvinyl alcohol.
4 . The composition as defined in claim 3 , wherein the first aqueous suspension includes between 0.1% and 10% w/v of the polyvinyl alcohol and wherein the polyvinyl alcohol has a mean molecular weight of between 10 kDa and 400 kDa.
5 . The composition as defined in claim 1 , wherein the polymer microcapsules are in a second aqueous suspension, and wherein the second aqueous suspension also includes polyvinyl alcohol.
6 . The composition as defined in claim 5 , wherein the second aqueous suspension includes between 1% and 5% w/v of the polyvinyl alcohol.
7 . The composition as defined in claim 1 , wherein the polymer microcapsules have a mean size between 20 μm and 100 μm and an upper limit size of 250 μm or less.
8 . The composition as defined in claim 1 , wherein a thickness of the polymer enclosing the first aqueous solution in the microcapsules is between 3% and 15% of a mean size of the microcapsules.
9 . The composition as defined in claim 1 , wherein the microcapsules further include at least one product selected from the group consisting of endolysins, lysostaphins, phage proteins, phage enzymatic formulations.
10 . The composition as defined in claim 1 , wherein the amino-acid based polymer is selected from
(1) a poly (ester amide urea) wherein at least one diol, at least one diacid, and at least one amino acid are linked together through an ester bond, an amide bond, and a urea bond,
(2) a poly (ester urethane urea) wherein at least one diol and at least one amino acid are linked together through an ester bond, a urethane bond, and a urea bond,
(3) a poly (ester amide urethane urea) wherein at least one diol, at least one diacid, and at least one amino acid are linked together through an ester bond, an amide bond, a urethane bond, and a urea bond,
(4) a poly (ester amide urethane) wherein at least one diol, at least one diacid, and at least one amino acid are linked together through an ester bond, an amide bond, and a urethane bond,
(5) a poly (ester urea) wherein at least one diol and at least one amino acid are linked together through an ester bond and a urea bond, and (6) a poly (ester urethane) wherein at least one diol and at least one amino acid are linked together through an ester bond and a urethane bond,
further wherein
the at least one diol is a compound of formula:
HO—R 1 —OH, R 1 is chosen from C 2 -C 12 alkylene optionally interrupted by at least one oxygen, C 3 -C 8 cycloalkylene, C 3 -C 10 cycloalkylalkylene,
the at least one diacid is a compound of formula:
HO—(CO)—R 3 —(CO)—OH, R 3 is C 2 -C 12 alkylene,
the at least one amino acid is chosen from naturally occurring amino acids and non-naturally occurring amino acid.
11 . The composition as defined in claim 10 , wherein the amino-acid based polymer is a poly (ester amide urea) comprising the following two blocks with random distribution thereof:
wherein R 1 is —(CH 2 ) 6 —, R 3 is —(CH 2 ) 8 — and both R 2 and R 4 are the side chain of L-leucine.
12 . The composition as defined in claim 11 , wherein the ratio of l:m ranges from 0.25:0.75 to 0.75:0.25, l+m=1.
13 . The composition as defined in claim 10 , wherein the amino-acid based polymer has a molecular weight between 40 kDa and 105 kDa.
14 . The composition as defined in claim 10 , wherein the amino-acid based polymer has a molecular weight between 40 kDa and 60 kDa.
15 . The composition as defined in claim 1 , wherein the composition is in liquid form.
16 . The composition as defined in claim 15 , wherein the composition has a viscosity small enough to allow pulverization through a nozzle.
17 . The composition as defined in claim 16 , wherein the polymer microcapsules are suspended in a solution including a poloxamer.
18 . The composition as defined in claim 17 , wherein the poloxamer is poloxamer 407 having a mean molecular weight of between 9500 kDa and 15000 kDa and in a concentration of between 10 and 30 percent.
19 . The composition as defined in claim 1 , wherein the composition is powder form.
20 . The composition as defined in claim 1 , wherein the composition is in gel form.
21 . The composition as defined in claim 1 , wherein the polymer microcapsules contain on average more than 4 active bacteriophages.
22 . The composition as defined in claim 1 , wherein the polymer microcapsules contain on average more than 100 active bacteriophages.
23 . The composition as defined in claim 1 , wherein the composition further includes active bacteriophages outside of the polymer microcapsules.
24 . The composition as defined in claim 1 , further comprising a drug selected from the set consisting of antibiotics, pain killer and hemostatic drug.
25 . The composition as defined in claim 1 , wherein the composition has a stability such that at least 1% of the active bacteriophages remain active after storage of the composition for one year at 4° C.
26 . The composition as defined in claim 1 , wherein the microcapsules have a size distribution with a standard deviation of 20% or less of the mean size.