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Compensatory Mechanisms in Acid–Base Disorders
Published in Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal, Principles of Physiology for the Anaesthetist, 2020
Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal
Titratable acidity refers to the hydrogen ions bound to filtered buffers in urine, and it is equal to the amount of alkali (NaOH) required to titrate the urine to a pH of 7.4. Urinary titratable acidity is due to the conversion of monohydrogen phosphate to dihydrogen phosphate in the tubule. At the maximal urine acidity of 4.5, all the urinary phosphate is in the form of dihydrogen phosphate. After all the bicarbonate ions in the tubular fluid are reabsorbed, excess H+ ions in the tubular fluid combine with monohydrogen phosphate to form dihydrogen phosphate. A bicarbonate ion is added to peritubular capillary blood for each dihydrogen phosphate ion produced. Other filtered buffers in the tubular fluid, including creatinine, β-hydroxybutyrate and sulphates, contribute only a minor extent to titratable acidity. The proximal tubule is the chief site for the formation of titratable acidity (Figure 48.3). The kidney can excrete H+ ions using the phosphate buffer system at a rate of 40 mmol per day. However, the availability of phosphate cannot be easily increased to increase acid excretion.
Acid–base physiology
Published in Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal, Principles of Physiology for the Anaesthetist, 2015
Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal
Titratable acidity refers to the hydrogen ions bound to filtered buffers in urine, and it is equal to the amount of alkali (NaOH) required to titrate the urine to a pH of 7.4. Urinary titratable acidity is due to the conversion of monohydrogen phosphate to dihydrogen phosphate in the tubule. At the maximal urine acidity of 4.5, all the urinary phosphate is in the form of dihydrogen phosphate. After all the bicarbonate ions in the tubular fluid are reabsorbed, excess H+ ions in the tubular fluid combine with monohydrogen phosphate to form dihydrogen phosphate. A bicarbonate ion is added to peritubular capillary blood for each dihydrogen phosphate ion produced. Other filtered buffers in the tubular fluid, including creatinine, β-hydroxybutyrate and sulphates, contribute only a minor extent to titratable acidity. The proximal tubule is the chief site for the formation of titratable acidity (Figure 8.6).
Acid–base disturbances
Published in Martin Andrew Crook, Clinical Biochemistry & Metabolic Medicine, 2013
At pH 7.4, most of the phosphate in plasma, and also in the glomerular filtrate, is monohydrogen phosphate (HPO42–), which can accept H+ to become dihydrogen phosphate (H2PO4−). Bicarbonate can continue to be generated within tubular cells, with H+, and to be returned to the body after all that in the filtrate has been reabsorbed. Therefore it can help to replace that used in extracellular buffering. The pKa of this buffer pair is about 6.8:
Effects of water-soluble additive on the release profile and pharmacodynamics of triptorelin loaded in PLGA microspheres
Published in Drug Development and Industrial Pharmacy, 2023
Xiaoyan He, Jiwei Liu, Tao Song, Yiying Sun, Xiaoyan Lu, Nuannuan Li, Kaoxiang Sun
Triptorelin acetate was purchased from Bachem AG (Bubendorf, Switzerland). PLGA (5050 DLG 2.5 A, LAKESHORE™ BIOMATERIALS) was supplied by Evonik Industries (Essen, Germany). Poly (vinyl alcohol) (PVA, Mw: 13,000–23,000) and chloral hydrate were purchased from Sigma-Aldrich (Shanghai, China). Polystyrenes were purchased from Macklin Reagent Co., Ltd (Shanghai, China). Octreotide was provided by ShengNuo Technology (Sichuan, China). Methanol, acetonitrile, tetrahydrofuran, anhydrous glucose, sodium hydroxide (NaOH), methylene chloride, hydrochloric acid (HCl), sodium monohydrogen phosphate (Na2HPO4) and sodium dihydrogen phosphate (NaH2PO4) were obtained from Aladdin Reagent Co., Ltd (Shanghai, China). Sodium chloride (NaCl), calcium chloride (CaCl2), phosphoric acid (H3PO4) and acetic acid were provided by Sinopharm Chemical Reagent Co., Ltd (Shanghai, China). All chemicals were of analytical grade as received commercially.
Mercury(II) decontamination using a newly synthesized poly(acrylonitrile-acrylic acid)/ammonium molybdophosphate composite exchanger
Published in Toxin Reviews, 2022
Adel A. El-Zahhar, Abubakr M. Idris
All chemicals used in this study were of analytical reagent grade and thus were used without further purification. AA was obtained from BDH (Poole, England), while AN was obtained from Merck (Darmstadt, Germany). Acetone and dimethylformamide (DMF), which were used as solvents, besides ammonium peroxysulfate (APS) and N,N-methylene bisacrylamide (MBA) were obtained from Sigma-Aldrich (Darmstadt, Germany). The catalyst N,N,Ń,Ń-tetramethylethylenediamine (TMED) was obtained from Across Organics. Ammonium molybdate and ammonium monohydrogen phosphate were supplied by Fluka AG (Buchs, Switzerland). Mercuric (II) chloride from Sigma-Aldrich was used for the preparation of the Hg(II) solution.
Hybrid chitosan-lipid nanoparticles of green tea extract as natural anti-cellulite agent with superior in vivo potency: full synthesis and analysis
Published in Drug Delivery, 2021
Sara A. Abosabaa, Mona G. Arafa, Aliaa Nabil ElMeshad
Green tea leaves was purchased from Egyptian market. Chitosan (LMW 100 000–300 000 kDa), sodium tripolyphosphate, lecithin (soybean lecithin − 94% phosphatidylcholine), caffeine, catechin. epicatechin, and epigallocatechin gallate were purchased from Sigma-Aldrich Chemical Co. (St. Louis, USA). Acetic acid and Ethanol were supplied by Pio Chem, Cairo, Egypt. Sodium dihydrogen phosphate, sodium monohydrogen phosphate, acetonitirile, phosphoric acid and chloroform were purchased from Fisher Scientific (Loughborough, Leicestershire, UK). Cellophane membrane 12–14 kDa supplied by Spectrum Medical Inc, (Raleigh, North Carolina).