Transmembrane pH-gradient polymersomes for the quantification of ammonia in body fluids

{
  "publication_number": "US11713376B2",
  "country": "US",
  "kind": "B2",
  "title": "Transmembrane pH-gradient polymersomes for the quantification of ammonia in body fluids",
  "abstract": "The present invention provides polymersomes comprising amphiphilic block-copolymers and their use to quantify ammonia in samples (e.g., body fluid samples). More particularly, it provides a polymersome comprising (a) a membrane, which comprises a block copolymer of poly(styrene) (PS) and poly(ethylene oxide) (PEO), wherein the PS/PEO molecular weight ratio is higher than 1.0 and lower than 4.0; and (b) a core which encloses an acid and at least one pH-sensitive dye. Compositions, strips and kits comprising the polymersomes are also provided along with methods of quantifying ammonia in a sample using the polymersomes, compositions and kit.",
  "claims": [
    "1. A method of using a polymersome comprising a membrane which comprises a block copolymer of poly(styrene) (PS) and poly(ethylene oxide) (PEO), wherein the PS/PEO molecular weight ratio is higher than 1.0 and lower than 4.0; and (b) a core which encloses an acid and at least one pH-sensitive dye, a composition comprising the polymersome, and at least one excipient, or a strip comprising the composition in solid form, for determining the concentration of ammonia in a sample, comprising: (a) contacting the polymersome, composition or strip with the sample; (b) determining at least one pH-dependent spectroscopic property in the polymersome- or composition-containing sample or the sample-containing strip; and (c) determining the ammonia concentration in the sample using the at least one pH-dependent spectroscopic property by referring to a standard curve.",
    "2. The method of claim 1, wherein the pH-dependent spectroscopic property is (i) a pH-dependent absorbance, the pH-sensitive dye is a pH-dependent absorbance dye and the standard curve is an absorbance standard curve; or (ii) a pH-dependent fluorescence intensity, the pH-sensitive dye is a pH-sensitive fluorescent dye and the standard curve is a fluorescence standard curve.",
    "3. The method of claim 1, wherein (b) further comprises determining at least one pH-independent spectroscopic property or at least one further pH-dependent spectroscopic property in the polymersome- or composition-containing sample or the sample-containing strip to calculate at least one spectroscopic property ratio, and wherein (c) determines the ammonia concentration in the polymersome- or composition-containing sample or the sample-containing strip using the at least one pH-dependent spectroscopic property ratio by referring to a spectroscopic property ratio standard curve.",
    "4. The method of claim 3, wherein the at least one pH-dependent spectroscopic property and the at least one pH-independent spectroscopic property are produced by the same pH-sensitive dye.",
    "5. The method of claim 3, wherein the spectroscopic property is (i) absorbance, and the pH-sensitive dye is a pH-sensitive absorbance dye; or (ii) fluorescence, and the pH-sensitive dye is a pH-sensitive fluorescent dye.",
    "6. The method of claim 1, wherein the pH within the polymersome core is between 2 and 6.5.",
    "7. The method of claim 1, wherein the at least one pH-sensitive dye comprises (i) a hydroxypyrene or one of its pH-sensitive fluorescent derivatives; (ii) a pyridylphenyloxazole or one of its pH-sensitive fluorescent derivatives; (iii) an aminonaphthalene or one of its pH-sensitive fluorescent derivatives; or (iv) cyanine or one of its pH-sensitive fluorescent derivatives.",
    "8. The method of claim 1, wherein the sample comprises a body fluid sample from a subject and/or a buffer.",
    "9. The method of claim 8, wherein the body fluid is a blood or blood fraction sample, a saliva sample, or a semen sample.",
    "10. The method of claim 9, wherein the body fluid has been pretreated with phenylalanine ammonia lyase.",
    "11. The method of claim 9, which is for (i) diagnosing an ammonia-associated disease or disorder or phenylketonuria in the subject, wherein an ammonia concentration in the sample that is higher than a reference ammonia concentration is an indication that the subject has an ammonia-associated disease or disorder or phenylketonuria; or for (ii) monitoring the efficiency of an anti-hyperammonemia or an anti-phenylketonuria treatment, wherein an ammonia concentration in the sample that is lower than a reference ammonia concentration is an indication that the anti-hyperammonemia or anti-phenylketonuria treatment is effective.",
    "12. The method of claim 1, wherein the block copolymer is a diblock copolymer.",
    "13. The method of claim 1, wherein the acid is (i) in a concentration that produces a pH between 1 and 6.5, between 2 and 6.5, between 2 and 6, between 2 and 5.5, or between 3 and 5.5, when the polymersome is hydrated.",
    "14. The method of claim 13, wherein the pH within the aqueous acidic solution is between 1 and 6.5, between 2 and 6.5, between 2 and 5.5, or between 3 and 5.5.",
    "15. The method of claim 1, wherein the at least one pH-sensitive dye comprises 8-hydroxypyrene-1,3,6-trisulfonate (HPTS), dextran-conjugated Lysosensor™ Yellow/Blue, 8-aminonaphthalene-1,3,6-trisulfonate (ANTS), or IRDye™ 680RD carboxylate.",
    "16. The method of claim 1, wherein the acid and the at least one pH-sensitive dye are different molecules.",
    "17. The method of claim 1, wherein the acid is a hydroxy acid.",
    "18. The method of claim 1, wherein the acid is a citric acid.",
    "19. The method of claim 1, wherein the acid and the at least one pH-sensitive dye are the same molecule.",
    "20. The method of claim 1, wherein the polymersome is prepared by a method comprising mixing an organic solvent containing the copolymer with an aqueous phase containing the acid and the at least one pH-sensitive dye.",
    "21. The polymersome of claim 20, wherein the organic solvent is water immiscible or partially water miscible.",
    "22. The method of claim 1, wherein the at least one excipient comprises a preservative, a cryoprotectant, a lyoprotectant, an antioxidant, or a combination of at least two thereof.",
    "23. The method of claim 1, wherein the composition is in a liquid or solid form."
  ],
  "description_excerpt": "The present invention relates to the composition and use of transmembrane pH-gradient polymersomes for quantifying ammonia in body fluids (e.g., serum, plasma, and saliva). More specifically, the present invention is concerned with quantifying this molecule to e.g., diagnose and monitor diseases or conditions such as hepatic encephalopathy.\n\nAmmonia (NH 3) is a neurotoxic endogenous metabolite which accumulates in patients suffering from various diseases and conditions (e.g., impaired liver function (e.g., due to liver cirrhosis, acute liver failure, portosystemic shunting, inborn errors of ammonia metabolism) (Matoori and Leroux ADDR 2015; 90:55-68)) or undergo certain treatments. Ammonia may also accumulate in other environments, such as soil and wastewaters.\n\nAmmonia in Body Fluids\n\nHigh blood ammonia levels (hyperammonemia) are associated with hepatic encephalopathy (HE), a serious neuropsychiatric condition with acute and chronic manifestations potentially resulting in death (Vilstrup et al. Hepatology 2014; 60:715-735). The prevalence of HE in cirrhotic patients is high (up to 20%) (Vilstrup et al. supra; Blachier et al. Journal of Hepatology 2013; 58:593-608). This chronic disorder usually progresses from low-grade (cognitive impairment) to serious (hyperammonemic coma, in some patients with lethal outcome) symptoms (Vilstrup et al. supra). The plasma ammonia cut-off value is at 50 μM for adults and 100 μM for infants (Matoori and Leroux supra). In acute hyperammonemic crises, serum ammonia levels of more than 1.5 mM were reported (Bergmann et al. Pediatrics 2014; 133:e1072-e1076).",
  "cpc": [
    "C08G 81/025",
    "A61K 47/10",
    "A61K 47/12",
    "A61K 47/18",
    "A61K 47/186",
    "A61K 47/20",
    "A61K 47/22",
    "A61K 47/34",
    "A61K 47/36",
    "A61K 9/1273",
    "B01J 13/04",
    "B01J 13/08",
    "B01J 13/12",
    "B01J 13/125",
    "C08K 5/19",
    "C08K 5/353",
    "C08K 5/42",
    "C08L 25/08",
    "C08L 53/00",
    "C08L 71/02",
    "C08L 87/005",
    "C09K 11/06",
    "G01N 2333/59",
    "G01N 2800/085",
    "G01N 2800/368",
    "G01N 33/54386",
    "G01N 33/582",
    "G01N 33/689",
    "G01N 33/84"
  ],
  "ipc": [
    "B01J 13/08",
    "C08G 81/02",
    "C08K 5/19",
    "C08K 5/353",
    "C08K 5/42",
    "G01N 33/84",
    "A61K 9/127",
    "B01J 13/12",
    "C09K 11/06",
    "G01N 33/68"
  ],
  "assignees": [
    "Eidgenoessische Technische Hochschule Zurich ETHZ"
  ],
  "inventors": [
    "Jean-Christophe Leroux",
    "Simon Matoori",
    "Olha Voznyuk Wuerthinger"
  ],
  "filing_date": "2018-09-10",
  "publication_date": "2023-08-01",
  "grant_date": "2023-08-01",
  "priority_date": "2017-09-12",
  "application_number": "US-201816645763-A",
  "family_id": "63686035",
  "cited_by_count": 16,
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