Clinical data | |
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Trade names | Osmitrol, Bronchitol, others |
Other names | d-Mannitol, mannite, manna sugar |
AHFS/Drugs.com | Monograph |
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Routes of administration | Intravenous, By mouth, inhalation |
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Pharmacokinetic data | |
Bioavailability | ~7% |
Metabolism | Liver, negligible |
Elimination half-life | 100 minutes |
Excretion | Kidney: 90% |
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ChEMBL | |
E number | E421 (thickeners, ...) |
CompTox Dashboard (EPA) | |
ECHA InfoCard | 100.000.647 |
Chemical and physical data | |
Formula | C6H14O6 |
Molar mass | 182.172 g·mol−1 |
3D model (JSmol) | |
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Mannitol is a type of sugar alcohol used as a sweetener and medication. [5] [6] It is used as a low calorie sweetener as it is poorly absorbed by the intestines. [5] As a medication, it is used to decrease pressure in the eyes, as in glaucoma, and to lower increased intracranial pressure. [7] [8] [6] Medically, it is given by injection or inhalation. [9] [10] Effects typically begin within 15 minutes and last up to 8 hours. [9]
Common side effects from medical use include electrolyte problems and dehydration. [9] Other serious side effects may include worsening heart failure and kidney problems. [9] [6] It is unclear if use is safe in pregnancy. [9] Mannitol is in the osmotic diuretic family of medications and works by pulling fluid from the brain and eyes. [9]
The discovery of mannitol is attributed to Joseph Louis Proust in 1806. [11] It is on the World Health Organization's List of Essential Medicines. [12] It was originally made from the flowering ash and called manna due to its supposed resemblance to the Biblical food. [13] [14] Mannitol is on the World Anti-Doping Agency's banned substances list due to concerns that it may mask prohibited drugs. [15]
In the United States, mannitol is indicated for the reduction of intracranial pressure and treatment of cerebral edema and elevated intraocular pressure. [3]
In the European Union, mannitol is indicated for the treatment of cystic fibrosis (CF) in adults aged 18 years and above as an add-on therapy to best standard of care. [4]
Mannitol is used intravenously to reduce acutely raised intracranial pressure until more definitive treatment can be applied, [16] e.g., after head trauma. While mannitol injection is the mainstay for treating high pressure in the skull after a bad brain injury, it is no better than hypertonic saline as a first-line treatment. In treatment-resistant cases, hypertonic saline works better. [17] Intra-arterial infusions of mannitol can transiently open the blood–brain barrier by disrupting tight junctions. [18] [19]
It may also be used for certain cases of kidney failure with low urine output, decreasing pressure in the eye, to increase the elimination of certain toxins, and to treat fluid build up. [9]
Intraoperative mannitol prior to vessel clamp release during renal transplant has been shown to reduce post-transplant kidney injury, but has not been shown to reduce graft rejection.[ medical citation needed ]
Mannitol acts as an osmotic laxative [3] [20] in oral doses larger than 20 g, [21] and is sometimes sold as a laxative for children.[ citation needed ]
The use of mannitol, when inhaled, as a bronchial irritant as an alternative method of diagnosis of exercise-induced asthma has been proposed. A 2013 systematic review concluded evidence to support its use for this purpose at this time is insufficient. [22]
Mannitol is commonly used in the circuit prime of a heart lung machine during cardiopulmonary bypass. The presence of mannitol preserves renal function during the times of low blood flow and pressure, while the patient is on bypass. The solution prevents the swelling of endothelial cells in the kidney, which may have otherwise reduced blood flow to this area and resulted in cell damage.
Mannitol can also be used to temporarily encapsulate a sharp object (such as a helix on a lead for an artificial pacemaker) while it passes through the venous system. Because the mannitol dissolves readily in blood, the sharp point becomes exposed at its destination.
Mannitol is also the first drug of choice to treat acute glaucoma in veterinary medicine. It is administered as a 20% solution intravenously. It dehydrates the vitreous humor and, therefore, lowers the intraocular pressure. However, it requires an intact blood-ocular barrier to work. [23]
Mannitol increases blood glucose to a lesser extent than sucrose (thus having a relatively low glycemic index [24] ) so is used as a sweetener for people with diabetes, and in chewing gums. Although mannitol has a higher heat of solution than most sugar alcohols, its comparatively low solubility reduces the cooling effect usually found in mint candies and gums. However, when mannitol is completely dissolved in a product, it induces a strong cooling effect. [25] Also, it has a very low hygroscopicity – it does not pick up water from the air until the humidity level is 98%. This makes mannitol very useful as a coating for hard candies, dried fruits, and chewing gums, and it is often included as an ingredient in candies and chewing gum. [26] The pleasant taste and mouthfeel of mannitol also makes it a popular excipient for chewable tablets. [27]
Mannitol can be used to form a complex with boric acid. This increases the acid strength of the boric acid, permitting better precision in volumetric analysis of this acid. [28]
Mannitol is the primary ingredient of mannitol salt agar, a bacterial growth medium, and is used in others.
Mannitol is used as a cutting agent [29] [30] in various drugs that are used intranasally (snorted), such as heroin and cocaine. A mixture of mannitol and fentanyl (or fentanyl analogs) in ratio 1:10 is labeled and sold as "China white", a popular heroin substitute.[ citation needed ]
Mannitol is a sugar alcohol with "50-70 percent of the relative sweetness of sugar, which means more must be used to equal the sweetness of sugar. Mannitol lingers in the intestines for a long time and therefore often causes bloating and diarrhea." [31]
Mannitol is contraindicated in people with anuria, severe hypovolemia, pre-existing severe pulmonary vascular congestion or pulmonary edema, irritable bowel syndrome (IBS), and active intracranial bleeding except during craniotomy. [3]
Adverse effects include hyponatremia and volume depletion leading to metabolic acidosis. [11]
Mannitol is an isomer of sorbitol, another sugar alcohol; the two differ only in the orientation of the hydroxyl group on carbon 2. [25] While similar, the two sugar alcohols have very different sources in nature, melting points, and uses.
Mannitol is classified as a sugar alcohol; that is, it can be derived from a sugar (mannose) by reduction. Other sugar alcohols include xylitol and sorbitol.
Mannitol is commonly produced via the hydrogenation of fructose, which is formed from either starch or sucrose (common table sugar). Although starch is a cheaper source than sucrose, the transformation of starch is much more complicated. Eventually, it yields a syrup containing about 42% fructose, 52% glucose, and 6% maltose. Sucrose is simply hydrolyzed into an invert sugar syrup, which contains about 50% fructose. In both cases, the syrups are chromatographically purified to contain 90–95% fructose. The fructose is then hydrogenated over a nickel catalyst into a mixture of isomers sorbitol and mannitol. Yield is typically 50%:50%, although slightly alkaline reaction conditions can slightly increase mannitol yields. [25]
Mannitol is one of the most abundant energy and carbon storage molecules in nature, produced by a plethora of organisms, including bacteria, yeasts, fungi, algae, lichens, and many plants. [32] Fermentation by microorganisms is an alternative to the traditional industrial synthesis. A fructose to mannitol metabolic pathway, known as the mannitol cycle in fungi, has been discovered in a type of red algae (Caloglossa leprieurii), and it is highly possible that other microorganisms employ similar such pathways. [33] A class of lactic acid bacteria, labeled heterofermentive because of their multiple fermentation pathways, convert either three fructose molecules or two fructose and one glucose molecule into two mannitol molecules, and one molecule each of lactic acid, acetic acid, and carbon dioxide. Feedstock syrups containing medium to large concentrations of fructose (for example, cashew apple juice, containing 55% fructose: 45% glucose) can produce yields 200 g (7.1 oz) mannitol per liter of feedstock. Further research is being conducted, studying ways to engineer even more efficient mannitol pathways in lactic acid bacteria, as well as the use of other microorganisms such as yeast [32] and E. coli in mannitol production. When food-grade strains of any of the aforementioned microorganisms are used, the mannitol and the organism itself are directly applicable to food products, avoiding the need for careful separation of microorganism and mannitol crystals. Although this is a promising method, steps are needed to scale it up to industrially needed quantities. [33]
Since mannitol is found in a wide variety of natural products, including almost all plants, it can be directly extracted from natural products, rather than chemical or biological syntheses. In fact, in China, isolation from seaweed is the most common form of mannitol production. [26] Mannitol concentrations of plant exudates can range from 20% in seaweeds to 90% in the plane tree. It is a constituent of saw palmetto ( Serenoa ). [34]
Traditionally, mannitol is extracted by the Soxhlet extraction, using ethanol, water, and methanol to steam and then hydrolysis of the crude material. The mannitol is then recrystallized from the extract, generally resulting in yields of about 18% of the original natural product. Another method of extraction is using supercritical and subcritical fluids. These fluids are at such a stage that no difference exists between the liquid and gas stages, so are more diffusive than normal fluids. This is considered to make them much more effective mass transfer agents than normal liquids. The super- or subcritical fluid is pumped through the natural product, and the mostly mannitol product is easily separated from the solvent and minute amount of byproduct.
Supercritical carbon dioxide extraction of olive leaves has been shown to require less solvent per measure of leaf than a traditional extraction – 141.7 g (5.00 oz) CO2 versus 194.4 g (6.86 oz) ethanol per 1 g (0.035 oz) olive leaf. Heated, pressurized, subcritical water is even cheaper, and is shown to have dramatically greater results than traditional extraction. It requires only 4.01 g (0.141 oz) water per 1 g (0.035 oz) of olive leaf, and gives a yield of 76.75% mannitol. Both super- and subcritical extractions are cheaper, faster, purer, and more environmentally friendly than the traditional extraction. However, the required high operating temperatures and pressures are causes for hesitancy in the industrial use of this technique. [33]
In the early 1880s, Julije Domac elucidated the structure of hexene and mannitol obtained from Caspian manna. He determined the place of the double bond in hexene obtained from mannitol and proved that it is a derivative of a normal hexene. This also solved the structure of mannitol, which was unknown until then. [35] [36] [37] [38]
The three studies [39] [40] [41] that originally found high-dose mannitol effective in treating severe head injury were the subject of an investigation. Published in 2007 after the lead author Dr Julio Cruz's death, the investigation questioned whether the studies had actually taken place. [42] The co-authors of the paper were not able to confirm the existence of the study patients, and the Federal University of São Paulo, which Cruz gave as his affiliation, had never employed him. As a result of doubt surrounding Cruz's work, an updated version of the Cochrane review excludes all studies by Julio Cruz, leaving only four studies. [7] Due to differences in selection of control groups, a conclusion about the clinical use of mannitol has not been reached.
Glucose is a sugar with the molecular formula C6H12O6. It is overall the most abundant monosaccharide, a subcategory of carbohydrates. It is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, using energy from sunlight. It is used by plants to make cellulose—the most abundant carbohydrate in the world—for use in cell walls, and by all living organisms to make adenosine triphosphate (ATP), which is used by the cell as energy.
Fructose, or fruit sugar, is a ketonic simple sugar found in many plants, where it is often bonded to glucose to form the disaccharide sucrose. It is one of the three dietary monosaccharides, along with glucose and galactose, that are absorbed by the gut directly into the blood of the portal vein during digestion. The liver then converts most fructose and galactose into glucose for distribution in the bloodstream or deposition into glycogen.
Sorbitol, less commonly known as glucitol, is a sugar alcohol with a sweet taste which the human body metabolizes slowly. It can be obtained by reduction of glucose, which changes the converted aldehyde group (−CHO) to a primary alcohol group (−CH2OH). Most sorbitol is made from potato starch, but it is also found in nature, for example in apples, pears, peaches, and prunes. It is converted to fructose by sorbitol-6-phosphate 2-dehydrogenase. Sorbitol is an isomer of mannitol, another sugar alcohol; the two differ only in the orientation of the hydroxyl group on carbon 2. While similar, the two sugar alcohols have very different sources in nature, melting points, and uses.
A sugar substitute is a food additive that provides a sweetness like that of sugar while containing significantly less food energy than sugar-based sweeteners, making it a zero-calorie or low-calorie sweetener. Artificial sweeteners may be derived through manufacturing of plant extracts or processed by chemical synthesis. Sugar substitute products are commercially available in various forms, such as small pills, powders, and packets.
Xylitol is a chemical compound with the formula C
5H
12O
5, or HO(CH2)(CHOH)3(CH2)OH; specifically, one particular stereoisomer with that structural formula. It is a colorless or white crystalline solid. It is classified as a polyalcohol and a sugar alcohol, specifically an alditol. Of the common sugar alcohols, only sorbitol is more soluble in water.
Cerebral edema is excess accumulation of fluid (edema) in the intracellular or extracellular spaces of the brain. This typically causes impaired nerve function, increased pressure within the skull, and can eventually lead to direct compression of brain tissue and blood vessels. Symptoms vary based on the location and extent of edema and generally include headaches, nausea, vomiting, seizures, drowsiness, visual disturbances, dizziness, and in severe cases, death.
Intracranial pressure (ICP) is the pressure exerted by fluids such as cerebrospinal fluid (CSF) inside the skull and on the brain tissue. ICP is measured in millimeters of mercury (mmHg) and at rest, is normally 7–15 mmHg for a supine adult. This equals to 9–20 cmH2O, which is a common scale used in lumbar punctures. The body has various mechanisms by which it keeps the ICP stable, with CSF pressures varying by about 1 mmHg in normal adults through shifts in production and absorption of CSF.
Sugar alcohols are organic compounds, typically derived from sugars, containing one hydroxyl group (−OH) attached to each carbon atom. They are white, water-soluble solids that can occur naturally or be produced industrially by hydrogenating sugars. Since they contain multiple (−OH) groups, they are classified as polyols.
Fructose malabsorption, formerly named dietary fructose intolerance (DFI), is a digestive disorder in which absorption of fructose is impaired by deficient fructose carriers in the small intestine's enterocytes. This results in an increased concentration of fructose. Intolerance to fructose was first identified and reported in 1956.
An osmotic diuretic is a type of diuretic that inhibits reabsorption of water and sodium (Na). They are pharmacologically inert substances that are given intravenously. They increase the osmolarity of blood and renal filtrate. This fluid eventually becomes urine.
Isomalt is a sugar substitute, a mixture of the two disaccharide alcohols 1,6-GPS and 1,1-GPM. It is used primarily for its sugar-like physical properties. It has little to no impact on blood sugar levels, and does not stimulate the release of insulin. It also does not promote tooth decay and is considered to be tooth-friendly. Its energy value is 2 kcal per gram, half that of sugars. It is less sweet than sugar, but can be blended with high-intensity sweeteners such as sucralose to create a mixture with the same sweetness as sucrose (‘sugar’).
D-Psicose (C6H12O6), also known as D-allulose or simply allulose, is an epimer of fructose that is used by some commercial food and beverage manufacturers as a low-calorie sweetener. Allulose occurs naturally in small quantities in a variety of foods. It was first identified in the 1940s, although the enzymes needed to produce it on an industrial scale were not discovered until the 1990s.
Isomaltulose is a disaccharide carbohydrate composed of glucose and fructose. It is naturally present in honey and sugarcane extracts and is also produced industrially from table sugar (sucrose) and used as a sugar alternative.
Osmotherapy is the use of osmotically active substances to reduce the volume of intracranial contents. Osmotherapy serves as the primary medical treatment for cerebral edema. The primary purpose of osmotherapy is to improve elasticity and decrease intracranial volume by removing free water, accumulated as a result of cerebral edema, from brain's extracellular and intracellular space into vascular compartment by creating an osmotic gradient between the blood and brain. Normal serum osmolality ranges from 280 to 290 mOsm/kg and serum osmolality to cause water removal from brain without much side effects ranges from 300 to 320 mOsm/kg. Usually, 90 mL of space is created in the intracranial vault by 1.6% reduction in brain water content. Osmotherapy has cerebral dehydrating effects. The main goal of osmotherapy is to decrease intracranial pressure (ICP) by shifting excess fluid from brain. This is accomplished by intravenous administration of osmotic agents which increase serum osmolality in order to shift excess fluid from intracellular or extracellular space of the brain to intravascular compartment. The resulting brain shrinkage effectively reduces intracranial volume and decreases ICP.
In enzymology, aldose reductase is an enzyme in humans encoded by the gene AKR1B1. It is an cytosolic NADPH-dependent oxidoreductase that catalyzes the reduction of a variety of aldehydes and carbonyls, including monosaccharides, and primarily known for catalyzing the reduction of glucose to sorbitol, the first step in polyol pathway of glucose metabolism.
Sorbitol dehydrogenase is a cytosolic enzyme. In humans this protein is encoded by the SORD gene.
Fructokinase, also known as D-fructokinase or D-fructose (D-mannose) kinase, is an enzyme of the liver, intestine, and kidney cortex. Fructokinase is in a family of enzymes called transferases, meaning that this enzyme transfers functional groups; it is also considered a phosphotransferase since it specifically transfers a phosphate group. Fructokinase specifically catalyzes the transfer of a phosphate group from adenosine triphosphate to fructose as the initial step in its utilization. The main role of fructokinase is in carbohydrate metabolism, more specifically, sucrose and fructose metabolism. The reaction equation is as follows:
In enzymology, a sorbitol-6-phosphate dehydrogenase (EC 1.1.1.140) is an enzyme that catalyzes the chemical reaction
Single cell oil, also known as Microbial oil consists of the intracellular storage lipids, triacyglycerols. It is similar to vegetable oil, another biologically produced oil. They are produced by oleaginous microorganisms, which is the term for those bacteria, molds, algae and yeast, which can accumulate 20% to 80% lipids of their biomass. The accumulation of lipids take place by the end of logarithmic phase and continues during station phase until carbon source begins to reduce with nutrition limitation.
Pseudohypoxia refers to a condition that mimics hypoxia, by having sufficient oxygen yet impaired mitochondrial respiration due to a deficiency of necessary co-enzymes, such as NAD+ and TPP. The increased cytosolic ratio of free NADH/NAD+ in cells (more NADH than NAD+) can be caused by diabetic hyperglycemia and by excessive alcohol consumption. Low levels of TPP results from thiamine deficiency.