Pharmaceutical composition comprising particles and methods of making same

1. An aqueous composition comprising one or more particles, wherein:

(a) each particle comprises a complex of at least one double-stranded polyribonucleotide, or a salt or solvate thereof, and at least one linear polyalkyleneimine, or a salt and/or solvate thereof, wherein

(i) the double-stranded polyribonucleotide is polyinosinic-polycytidylic acid [poly(I:C)], and

(ii) the weight average molecular weight of the linear polyalkyleneimine is between 17 and 23 kDa and has a molecular weight polydispersity index of below 1.5;

(b) at least 90% of the particles have a mono-modal diameter distribution of below 300 nm;

(c) the one or more particles each have a z-average diameter of less than or equal to 150 nm measured according to ISO 22412:2008; and

(d) the aqueous composition has a zeta potential equal to or greater than 30 mV measured according to ISO 13099-2:2012.

2. The aqueous composition according to claim 1 , wherein at least 90% of the particles have a mono-modal diameter distribution of between 30 nm and 150 nm.

3. The aqueous composition according to claim 1 , wherein at least 40% of the double-stranded polyribonucleotides comprised in the particles have at least 850 base pairs, and at least 50% of the double-stranded polyribonucleotides comprised in the particles have between 400 and 5000 base pairs.

4. The aqueous composition according to claim 1 , wherein the aqueous composition has a zeta potential of between 35 mV and 50 mV.

5. The aqueous composition according to claim 1 , wherein:

(i) between 5% and 60% of the double-stranded polyribonucleotides have less than 400 base pairs;

(ii) between 20% and 45% of the double-stranded polyribonucleotides have between 400 and 850 base pairs;

(iii) between 20% and 70% of the double-stranded polyribonucleotides have between 850 and 5000 base pairs; and/or

(iv) between 0% and 10% of the double-stranded polyribonucleotides have more than 5000 base pairs.

6. The aqueous composition according to claim 1 , wherein the linear polyalkyleneimine is a linear polyethyleneimine.

7. The aqueous composition according to claim 1 , wherein the weight average molecular weight and the polydispersity index of the linear polyalkyleneimine is determined for the polyalkyleneoxide precursor to the polyalkyleneimine as measured according to ISO 16014:2012.

8. The aqueous composition according to claim 1 , wherein the at least one double-stranded polyribonucleotide composition contains poly(I:C) at a concentration of at least 0.5 mg/ml.

9. The aqueous composition according to claim 1 , further comprising at least one pharmaceutically acceptable carrier, organic solvent, excipient and/or adjuvant.

10. The aqueous composition according to claim 1 , further comprising at least one compound selected from an organic compound, an inorganic compound, a nucleic acid, an aptamer, a peptide, and/or a protein.

11. The aqueous composition according to claim 1 , further comprising glucose or mannitol in a concentration of between 1 and 10% (weight/volume).

12. The aqueous composition according to claim 1 , wherein the aqueous composition has a pH of between 2 and 4, and/or an osmolarity of between 200 and 600 mOsm/kg.

13. An aqueous composition comprising the one or more particles according to claim 1 , wherein each respective particle is formed at a ratio of a number of moles of nitrogen of the polyalkyleneimine to a number of moles of phosphorus of the double-stranded polyribonucleotide that is equal to or greater than 2.5.

14. The aqueous composition according to claim 13 , wherein the aqueous composition is formed by a complex of at least 0.5 mg of poly(I:C) per ml of the total volume of the composition.

15. An aqueous composition according to claim 13 , wherein the aqueous composition is formed by additionally adding glucose or mannitol at a concentration of between 1 and 10% (weight/total volume of the composition).

16. A composition obtained by lyophilizing the aqueous composition according to claim 1 .

17. A method for preparing an aqueous composition comprising the one or more particles of claim 1 , comprising:

(a) preparing a first aqueous solution of at least one double-stranded polyribonucleotide, or a salt or solvate thereof, and a second aqueous solution of at least one polyalkyleneimine, or a salt or solvate thereof;

(b) independently filtering each respective first and second aqueous solution through a filter having a pore diameter of less than or equal to 500 nm thereby forming a corresponding first and second sterilized solution;

(c) mixing each resulting first and second sterilized solution in a mixing chamber thereby forming the aqueous composition,

(i) wherein one of the respective first and second sterilized solutions is introduced into the other respective sterilized solution in the mixing chamber, optionally by injection, at a rate of greater than or equal to 1 ml/min, or

(ii) wherein each respective first and second sterilized solution is introduced into the mixing chamber simultaneously, optionally by injection, at a rate of greater than or equal to 1 ml/min.

18. The method according to claim 17 , further comprising:

(d) filtering the resulting aqueous composition through a filter having a pore diameter of less than or equal to 600 nm to thereby form a filtrate, or centrifuging the resulting aqueous composition at a speed of greater than or equal to 22480 m/s 2 to form a supernatant, wherein the resulting aqueous composition, filtrate or supernatant are optionally lypholized.

19. The method according to claim 17 , wherein one or both of the respective first and second aqueous solutions each further comprise a pharmaceutically acceptable carrier, organic solvent, excipient and/or adjuvant.