This is a working overview of Karl Fischer titration, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2025-10-14. Anything still debated is marked as such rather than presented as settled.
Creatine monohydrate is a crystalline compound formed from creatine and one molecule of water. Its systematic name is N-(aminoiminomethyl)-N-methylglycine monohydrate, and it appears as a white, odorless powder with limited solubility in water. The monohydrate is the most common solid form used in research and commercial products because it is stable under dry conditions. The anhydrous form lacks the water of crystallization and differs slightly in molar mass. Both forms participate in the same biochemical reactions once dissolved.
In the body, creatine is synthesized from the amino acids arginine, glycine, and methionine, primarily in the liver and kidneys. It is transported to muscle and other tissues, where it is phosphorylated to phosphocreatine by creatine kinase. This phosphagen system provides a rapid source of adenosine triphosphate during short, intense contractions. Dietary creatine comes mainly from meat and fish, and the body's total pool is influenced by both synthesis and intake.
As a supplement, creatine monohydrate is studied for its effects on muscle performance and recovery. The compound is often described as an ergogenic aid, meaning it may support physical work capacity. Research typically compares it with placebo or other forms, such as citrate or nitrate, under controlled conditions. Questions remain about the optimal dose and long-term effects in different populations, and findings are not uniform across all studies. The monohydrate form remains the most extensively tested.
Quality control of creatine monohydrate relies on a combination of identity, purity, and moisture tests. High-performance liquid chromatography with ultraviolet detection is widely used to separate creatine from creatinine and other related nitrogenous compounds. Spectroscopic methods such as infrared and nuclear magnetic resonance provide structural confirmation. Because the material is a hydrate, water content is measured separately, often by Karl Fischer titration. These tests together establish whether a lot meets a defined specification.
Manufacturing processes can leave trace amounts of dicyandiamide, creatinine, or residual solvents, depending on the synthetic route and purification steps. Heavy metals, arsenic, and microbial contamination are also monitored for food or pharmaceutical grades. Particle size distribution can affect dissolution behavior and blending uniformity, so it may be specified for certain applications. Analytical results are reported on a dry basis or as-is basis, and the difference matters when comparing certificates of analysis. Open questions remain about how minor impurities influence long-term stability under varied storage conditions.
Stability studies typically examine the effects of temperature, humidity, and light on creatine monohydrate. Sealed containers stored in cool, dry conditions help limit moisture uptake and hydrolysis. Elevated temperature and high relative humidity can accelerate conversion to creatinine, especially in aqueous solutions. In solid dosage forms, excipients and processing steps may also affect stability. Published stability data are not fully consistent across studies because test conditions and analytical methods vary.
| Property | Value | Notes |
|---|---|---|
| Chemical formula | C4H9N3O2·H2O | Monohydrate form; anhydrous is C4H9N3O2 |
| Molar mass | 149.15 g/mol | For the monohydrate |
| Appearance | White crystalline powder | Odorless, slightly bitter taste |
| Solubility in water | ~13 g/L at 25 °C | Poorly soluble; increases with temperature |
| CAS Registry Number | 6020-87-7 | For creatine monohydrate |
Creatine monohydrate is a crystalline compound formed when one molecule of creatine binds with one molecule of water. Creatine itself is a nitrogen-containing organic acid involved in cellular energy transfer, particularly in muscle and nerve tissue. The monohydrate form is the most common solid form used in research and commercial products because it is relatively stable and easy to handle. Its molecular formula is C4H9N3O2·H2O, and its molar mass is about 149.15 grams per mole.
In the human body, creatine is synthesized mainly in the liver and kidneys from the amino acids glycine, arginine, and methionine. Dietary sources include meat, fish, and other animal tissues, which supply preformed creatine. Because plant foods contain little or no creatine, dietary intake varies widely among populations. The compound is stored largely in skeletal muscle, where it is converted to phosphocreatine and used to regenerate adenosine triphosphate during short bursts of activity.
Creatine monohydrate is a crystalline compound formed from creatine and one molecule of water. Creatine itself is a nitrogen-containing organic acid that occurs in vertebrate muscle and other tissues. The monohydrate designation refers to the water included in the crystal lattice, not to water added during manufacturing. Its chemical formula is commonly written as C4H9N3O2·H2O. The solid is typically a white, odorless powder with low solubility in water at room temperature. It is one of several creatine forms described in scientific and commercial literature.
The compound was identified in the nineteenth century after chemists isolated a nitrogenous substance from meat extracts. Later work established its role in muscle energy metabolism and its conversion to phosphocreatine. Chemical synthesis of creatine followed, and industrial production made the monohydrate widely available as a purified powder. Interest expanded in the late twentieth century when researchers began studying creatine supplementation and muscle physiology. Historical accounts sometimes differ on exact dates and attributions, but the broad sequence from tissue extracts to synthetic production is well documented.
Volanesorsen was approved by the European Medicines Agency (EMA) for the treatment of familial chylomicronaemia syndrome in May 2019. In January 2013 mipomersen (marketed as Kynamro) was approved by the FDA for the treatment of homozygous familial hypercholesterolemia. Inotersen received FDA approval for the treatment of hereditary transthyretin-mediated amyloidosis in October 2018. The application for inotersen was granted orphan drug designation. It was developed by Ionis Pharmaceuticals and licensed to Akcea Therapeutics. Patisiran (sold under Onpattro) was developed by Alnylam Pharmaceuticals, and also approved for use in the US and EU in 2018 with orphan drug designation. Its mechanism-of-action is the active substance of small interfering RNA (siRNA), which allows it to interfere with and block the production of transthyretin. As such, it was the first FDA-approved siRNA therapeutic.
The structure of CARD11 involves multiple domains that impact the protein's ability to activate BCL10 and NF-κB activity. CARD11 has a CARD domain, a serine-threonine rich region, is associated with the N-terminus, which is essential for NF-κB signaling activity. The region following the CARD domain is highly coiled. In deleting the CARD domain, all NF-κB signaling activity was prevented. The CARD domain on CARD11 interacts with the CARD domain on BCL10 to initiate the signaling pathway. On the C-terminus of CARD11 there is the MAGUK domain that is associated with the cell membrane. This domain is often referred to as the inhibitory domain. Protein kinase C activates CARD11 by phosphorylating serine residues within the inhibitory domain. CARD11 has been shown to interact with BCL10. This interaction occurs between the CARD domain on BCL10 and the CARD domain on CARD11, and results in signal propagation and NF-κB activation. Human CARD11 genome location and CARD11 gene details page in the UCSC Genome Browser.
The final step in the non-mevalonate pathway is carried out by the enzyme 4-hydroxy-3-methylbut-2-enyl diphosphate reductase, which gives a mixture of dimethylallyl pyrophosphate and isopentenyl pyrophosphate in the ratio of five to one. The products are then used in terpenoid biosynthesis. HMB-PP is an essential metabolite in most pathogenic bacteria including Mycobacterium tuberculosis as well as in malaria parasites, but is absent from the human host. HMB-PP is the physiological activator ("phosphoantigen") for human Vγ9/Vδ2 T cells, the major γδ T cell population in peripheral blood. With a bioactivity of 0.1 nM it is 10,000-10,000,000 times more potent than any other natural compound, such as IPP or alkyl amines. HMB-PP functions in this capacity by binding the B30.2 domain of BTN3A1. 4-hydroxy-3-methylbut-2-enyl+pyrophosphate at the U.S. National Library of Medicine Medical Subject Headings (MeSH)
Sources: en.wikipedia.org
Outbreaks of disease Food-born illness Bioterrorism Natural disasters APHL plays a critical role in crisis response to these public health emergencies through the Laboratory Response Network (LRN). The LRN was formed in 1999 in a cooperative effort between APHL, the CDC and FBI to rapidly detect, and respond to public health emergencies. The Department of Defense has joined in the effort to support biological response activities. In addition to their leadership during times of crisis, APHL has a strong focus on preparing public health laboratories on how to respond to emergencies when they happen through training and capacity-building, as well as creating model frameworks that labs around the country can use in order to have procedures in place to handle a crisis when it happens.
To annotate the vast amounts of available NGS data, currently a large number of SNPs annotation tools are available. Some of them are specific to specific SNPs while others are more general. Some of the available SNPs annotation tools are as follows SNPeff, Ensembl Variant Effect Predictor (VEP), ANNOVAR, FATHMM, PhD-SNP, PolyPhen-2, SuSPect, F-SNP, AnnTools, SeattleSeq, SNPit, SCAN, Snap, SNPs&GO, LS-SNP, Snat, TREAT, TRAMS, Maviant, MutationTaster, SNPdat, Snpranker, NGS – SNP, SVA, VARIANT, SIFT, LIST-S2, PhD-SNP and FAST-SNP. The functions and approaches used in SNPs annotation tools are listed below. Variant annotation tools use machine learning algorithms to predict variant annotations. Different annotation tools use different algorithms. Common algorithms include: Interval/Random forest-eg.MutPred, SNPeff Neural networks-eg.SNAP Support Vector Machines-e.g. PhD-SNP, SNPs&GO Bayesian classification-eg.PolyPhen-2
4-Aminosalicylic acid was first synthesized by Seidel and Bittner in 1902. It was rediscovered by the Swedish chemist Jörgen Lehmann upon the report that the tuberculosis bacterium avidly metabolized salicylic acid. Lehmann first tried PAS as an oral TB therapy late in 1944. The first patient made a dramatic recovery. The manner in which Lehmann discovered the TB indication for PAS was salient in the history of drug discovery because it was a rare example in which a person mentally postulated the exact molecule for a drug based on their acquired knowledge of the biochemical behaviour of an analogue of the molecule. The drug proved better than streptomycin, which had nerve toxicity and to which TB could easily develop resistance. In 1948, researchers at Britain's Medical Research Council demonstrated that combined treatment with streptomycin and PAS was superior to either drug alone, and established the principle of combination therapy for tuberculosis. 4-Aminosalicylic acid has many names including para-aminosalicylic acid, p-aminosalicylic acid, 4-ASA, and simply P.
Sources: en.wikipedia.org
Lipid vesicles or liposomes are approximately spherical pockets that are enclosed by a lipid bilayer. These structures are used in laboratories to study the effects of chemicals in cells by delivering these chemicals directly to the cell, as well as getting more insight into cell membrane permeability. Lipid vesicles and liposomes are formed by first suspending a lipid in an aqueous solution then agitating the mixture through sonication, resulting in a vesicle. Measuring the rate of efflux from the inside of the vesicle to the ambient solution allows researchers to better understand membrane permeability. Vesicles can be formed with molecules and ions inside the vesicle by forming the vesicle with the desired molecule or ion present in the solution. Proteins can also be embedded into the membrane through solubilizing the desired proteins in the presence of detergents and attaching them to the phospholipids in which the liposome is formed. These provide researchers with a tool to examine various membrane protein functions.
Cells that stop dividing (post-mitotic) and differentiate into neurons early in cortical development are important in laying the groundwork on which other developing neurons can be guided to their proper destination. Tbr1 aids in neuronal migration in the early development of the cerebral cortex. It is largely expressed in post-mitotic neurons of the preplate, which forms a foundation upon which neurons are able to grow and move. As a transcription factor, Tbr1 modulates the expression of RELN, which encodes the Reln protein that forms part of the extracellular matrix of cells. Thus, through regulation of Reln expression, Tbr1 regulates the formation of the matrix through which neurons migrate. Without Tbr1, neurons fail to migrate properly.
Imaging technologies are often essential to medical diagnosis, and are typically the most complex equipment found in a hospital including: fluoroscopy, magnetic resonance imaging (MRI), nuclear medicine, positron emission tomography (PET), PET-CT scans, projection radiography such as X-rays and CT scans, tomography, ultrasound, optical microscopy, and electron microscopy. An implant is a kind of medical device made to replace and act as a missing biological structure (as compared with a transplant, which indicates transplanted biomedical tissue). The surface of implants that contact the body might be made of a biomedical material such as titanium, silicone or apatite depending on what is the most functional. In some cases, implants contain electronics, e.g. artificial pacemakers and cochlear implants. Some implants are bioactive, such as subcutaneous drug delivery devices in the form of implantable pills or drug-eluting stents.
Sources: en.wikipedia.org
It is a compound made of creatine bound to one water molecule. It appears as a white crystalline powder and is the most common solid form of creatine used in research and supplements.
Creatine is converted to phosphocreatine in muscle, which helps regenerate adenosine triphosphate during brief, high-intensity activity. The body also obtains creatine from foods such as meat and fish.
The creatine molecule is the same whether from food or supplements, but the monohydrate form includes a water molecule in its crystal structure. Once dissolved, the monohydrate and food-derived creatine are chemically identical in the body.
Purity is commonly assessed by HPLC, which separates creatine from related compounds such as creatinine. Water content is measured separately by Karl Fischer titration. Together these results help calculate the actual creatine content in a sample.