Buffered compositions for dialysis

Abstract

Acid concentrates, and dialysate compositions prepared therefrom, contain citric acid and an effective amount of a buffering agent selected from acetate and/or lactate. The buffering agent allows a physiologically acceptable amount of citrate to maintain the desired pH of the dialysate.

What is claimed is: 
     
         1 . A method of forming a dialysate precursor composition comprising mixing treated water, chloride, citrate, at least one buffering anion selected from acetate and/or lactate, and at least one physiologically-acceptable cation to provide a composition having chloride at a concentration ranging from about 1,000 to about 7,000 mEq/L, citrate at a concentration ranging from about 20 to about 900 mEq/L, and at least one buffering anion selected from acetate and lactate at a concentration ranging from about 0.01 to about 150 mEq/L. 
     
     
         2 . The method of  claim 1  comprising citrate at a concentration ranging from about 70 to about 150 mEq/L. 
     
     
         3 . The method of  claim 1  wherein the buffering anion is acetate at a concentration ranging from about 0.3 to about 125 mEq/L. 
     
     
         4 . The method of  claim 1  wherein the buffering anion is lactate at a concentration ranging from about 0.3 to about 125 mEq/L. 
     
     
         5 . The method of  claim 1  wherein the physiologically-acceptable cation is selected from a group consisting of hydrogen, sodium, potassium, calcium, magnesium, and combinations thereof. 
     
     
         6 . The method of  claim 1 , further comprising mixing the dialysate precursor with a sugar selected from glucose, poly(glucose) and fructose, at a concentration of less than about 2,700 g/L. 
     
     
         7 . The method of  claim 1  wherein the citrate is in the form of at least one of citric acid or a salt thereof selected from a group consisting of sodium dihydrogen citrate, disodium hydrogen citrate, trisodium citrate, trisodium citrate dihydrate, potassium dihydrogen citrate, dipotassium hydrogen citrate, calcium citrate, and magnesium citrate. 
     
     
         8 . The method of  claim 1  wherein the buffering anion acetate is in the form of at least one of acetic acid or a salt thereof selected from a group consisting of sodium acetate, sodium acetate trihydrate, potassium acetate, calcium acetate, calcium acetate monohydrate, magnesium acetate, and magnesium acetate tetrahydrate. 
     
     
         9 . The method of  claim 1  wherein the buffering anion lactate is in the form of at least one of lactic acid or a salt thereof selected from a group consisting of sodium lactate, potassium lactate, calcium lactate and magnesium lactate trihydrate. 
     
     
         10 . The method of  claim 1 , further comprising mixing the dialysate precursor composition with treated water, wherein the treated water meets or exceeds the purity requirements established by AAMI for dialysate, and all other components have at least USP-grade purity. 
     
     
         11 . The method of  claim 1  comprising chloride at a concentration ranging from about 2,000 to about 5,000 mEq/L; citrate at a concentration ranging from about 70 to about 150 mEq/L; acetate at a concentration ranging from about 0.3 to about 125 mEq/L; at least one physiologically-acceptable cation selected from hydrogen, sodium at a concentration ranging from about 2,000 to about 5,000 mEq/L, potassium at a concentration of less than about 250 mEq/L, calcium at a concentration of less than about 250 mEq/L, magnesium at a concentration of less than about 100 mEq/L; and dextrose at a concentration of less than about 2,700 g/L, where the composition meets or exceeds the AAMI-quality standard set for dialysate. 
     
     
         12 . A method of forming a buffered dialysate composition comprising mixing a dialysate precursor composition with an aqueous bicarbonate-containing solution, the dialysate precursor composition comprising treated water, chloride, citrate, at least one buffering anion selected from acetate and lactate, and at least one physiologically-acceptable cation to provide a dialysate composition having chloride at a concentration ranging from about 44 to about 143 mEq/L, citrate at a concentration ranging from about 1.5 to about 30 mEq/L, and at least one buffering anion selected from acetate and lactate at a concentration ranging from about 0.01 to about 3.6 mEq/L. 
     
     
         13 . The method of  claim 12  wherein the bicarbonate-containing solution further comprises a base selected from a group consisting of carbonate, lactate, citrate, and acetate at a concentration ranging from about 25 to about 45 mEq/L. 
     
     
         14 . The method of  claim 12  wherein the physiologically-acceptable cation is selected from a group consisting of hydrogen, sodium, potassium, calcium, magnesium, and combinations thereof. 
     
     
         15 . The method of  claim 12  wherein the composition further comprises a sugar selected from dextrose, icodextrin, and fructose at a concentration of less than about 45 g/L. 
     
     
         16 . The method of  claim 12  wherein the dialysate composition comprises chloride at a concentration ranging from about 44 to about 143 mEq/L; citrate at a concentration ranging from about 1.5 to about 4.5 mEq/L, the buffering anion acetate at a concentration ranging from about 0.01 to about 3.6 mEq/L; bicarbonate at a concentration ranging from about 25 to about 45 mEq/L; at least one physiologically-acceptable cation selected from hydrogen, sodium at a concentration ranging from about 69 to about 188 mEq/L, potassium at a concentration of less than about 5 mEq/L, calcium at a concentration of less than about 5 mEq/L, and magnesium at a concentration of less than about 2 mEq/L; and glucose at a concentration of less than about 45 g/L; where the composition meets or exceeds the AAMI-quality standards set for dialysate. 
     
     
         17 . An aqueous acid-concentrate composition comprising water, chloride at a concentration of about 1,000 to about 7,000 mEq/L; citrate at a concentration ranging from about 20 to about 900 mEq/L; and sufficient physiologically-acceptable cations to provide for a neutral composition, where the composition has a pH of less than 4, and does not contain any of acetate, bicarbonate or lactate. 
     
     
         18 . A peritoneal dialysate composition comprising sterile water, citrate at a concentration of about 0.5-6 mEq/L; chloride at a concentration of about 20-200 mEq/L; bicarbonate at a concentration of about 5-100 mEq/L assuming all carbonate-containing species are in the bicarbonate form, glucose at a concentration of about 10-100 g/L; and a sufficient number of physiologically-acceptable cations to neutralize all of the citrate, chloride, bicarbonate, and any other anionic species that may be present in the composition. 
     
     
         19 . A method for performing dialysis comprising combining a first solution with a second solution to form dialysate, and performing hemodialysis with the dialysate, the first solution comprising citrate, buffer, and water, the second solution comprising bicarbonate and water.