This is a working overview of HPLC, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-04-08 and is reviewed periodically as new material appears.
Identity and purity are assessed with several complementary methods. High-performance liquid chromatography can separate creatine from creatinine and related impurities, often with ultraviolet detection. Nuclear magnetic resonance and infrared spectroscopy provide structural confirmation, while Karl Fischer titration measures water content. Elemental analysis and mass spectrometry may be used for additional confirmation, especially in research or forensic settings. No single method captures every quality attribute, so laboratories typically combine results and compare them against a specification.
Creatine monohydrate is sold as a dietary ingredient in some countries and as a food supplement in others. Regulatory frameworks vary, so purity limits, labeling rules, and permitted claims are not globally uniform. In the United States, it falls under dietary supplement rules, whereas the European Union treats it as a food supplement ingredient. Pharmacopeial monographs, where they exist, can provide public quality standards, but not every product is required to meet them. Questions about long-term effects and patterns of use remain areas of active study rather than settled regulatory findings.
Regulatory status varies by country. In the United States, creatine monohydrate is sold as a dietary supplement ingredient, while in the European Union it is placed on the market as a food supplement component. Some jurisdictions have established purity monographs or permitted health claims, while others treat it as a novel food or require notification. Product labels may state the amount of creatine monohydrate or the equivalent creatine content, and the two figures can differ. Independent testing programs sometimes check identity, potency, and contaminant limits.
Creatine monohydrate is stable under dry, cool conditions but can degrade when exposed to moisture and heat. In solution, it undergoes hydrolysis to creatinine, a cyclic derivative with little role in phosphagen energy transfer. The rate of conversion increases with temperature, storage time, and acidic or alkaline pH. Solid material kept in a sealed container at room temperature generally retains its composition for extended periods. Moisture uptake is a primary concern because it can accelerate breakdown and caking.
Analytical laboratories commonly use high-performance liquid chromatography to separate creatine from creatinine and related impurities. Ion chromatography, nuclear magnetic resonance, and titration assays can also quantify the compound. Water content is measured by Karl Fischer titration or loss on drying, because the monohydrate has a defined theoretical water fraction. Particle size, bulk density, and flowability are physical properties that affect blending and capsule filling. These measurements support quality control and help verify that a lot matches its specification.
| Property | Value | Notes |
|---|---|---|
| Purity (typical) | ≥99% by HPLC | Supplement and pharmacopeial grades vary |
| Water content | ≈12.1% theoretical | Measured by Karl Fischer titration |
| Creatinine limit | Often ≤0.1% in pharmacopeial grade | Supplement specifications may differ |
| Storage conditions | 15–25 °C, low humidity | Away from heat and acidic environments |
| Common analytical methods | HPLC–UV, NMR, FTIR, Karl Fischer | Used for identity, assay, and water content |
==== Ontario Student Assistance Program ==== In early 2026, the Ford government announced changes to the Ontario Student Assistance Program (OSAP) and billions in new funding for Ontario's financially struggling colleges and universities. The government announced the end of the tuition freeze for public colleges and universities, allowing them to raise fees by up to two percent per year over three years, and announced changes to OSAP funding, with grants reduced to a maximum of 25 percent for grants, and loans increased to a minimum of 75 percent; the changes saw protests from students across the province. This followed changes made to the program by the government in January 2019, which included a 10% tuition fee reduction for all programs in 2019–20, followed by a freeze in 2020–21, and the cutting of the OSAP budget from $2 billion to $1.4 billion.
== Research == Mitra's research aims to study the complex biological systems from a “theoretical engineering” perspective. He combines theoretical, computational and experimental approaches and currently understanding how brains work. Professor Mitra initiated the idea of brain-wide mesoscale circuit mapping and founded the Brain Architecture Project, including collaborations with RIKEN Brain Science Institute and Monash University. He has published over 240 research articles in peer-reviewed journals such as Nature, Science, PNAS, PRL with an H-index of 70 and holds thirty-one U.S. patents. He has also co-authored a book titled Observed Brain Dynamics published by the Oxford University Press and has written pieces for Scientific American.
== Safety == In vivo dermal sensitization studies according to OECD 429 confirmed EDC is a strong skin sensitizer, showing a response at <0.01 wt% in the Local Lymph Node Assay (LLNA) placing it in Globally Harmonized System of Classification and Labelling of Chemicals (GHS) Dermal Sensitization Category 1A. Thermal hazard analysis by differential scanning calorimetry (DSC) shows EDC poses minimal explosion risks.
=== Serotonin–norepinephrine reuptake inhibitors === Serotonin–norepinephrine reuptake inhibitor (SNRIs) include venlafaxine and duloxetine drugs. Venlafaxine, in extended release form, and duloxetine, are indicated for the treatment of GAD. SNRIs are as effective as SSRIs in the treatment of anxiety disorders.
=== Mechanism of action === Bulevirtide binds and inactivates the sodium/bile acid cotransporter, blocking both hepatitis B and hepatitis D viruses from entering hepatocytes. The hepatitis B virus uses its surface lipopeptide pre-S1 for docking to mature liver cells via their sodium/bile acid cotransporter (NTCP) and subsequently entering the cells. Myrcludex B is a synthetic N-acylated pre-S1 that can also dock to NTCP, blocking the virus's entry mechanism. Bulevirtide is also effective against hepatitis D because the hepatitis D virus uses the same entry receptor as the hepatitis B virus and is only effective in the presence of a hepatitis B virus infection. Pre-clinical data in mice suggests that pharmacological inhibition of NTCP-mediated bile salt uptake may also be effective to lower hepatic bile salt accumulation in cholestatic conditions. This reduces hepatocellular damage. An increased ratio of phospholipid to bile salts seen in bile upon NTCP inhibition may further contribute to the protective effect as bile salts are less toxic in presence of phospholipids.
Sources: en.wikipedia.org
==== Bone metabolism ==== In mice and humans, alterations in serotonin levels and signalling have been shown to regulate bone mass. Mice that lack brain serotonin have osteopenia, while mice that lack gut serotonin have high bone density. In humans, increased blood serotonin levels have been shown to be a significant negative predictor of low bone density. Serotonin can also be synthesized, albeit at very low levels, in the bone cells. It mediates its actions on bone cells using three different receptors. Through 5-HT1B receptors, it negatively regulates bone mass, while it does so positively through 5-HT2B receptors and 5-HT2C receptors. There is very delicate balance between physiological role of gut serotonin and its pathology. Increase in the extracellular content of serotonin results in a complex relay of signals in the osteoblasts culminating in FoxO1/ Creb and ATF4 dependent transcriptional events. Following the 2008 findings that gut serotonin regulates bone mass, the mechanistic investigations into what regulates serotonin synthesis from the gut in the regulation of bone mass have started. Piezo1 has been shown to sense RNA in the gut and relay this information through serotonin synthesis to the bone by acting as a sensor of single-stranded RNA (ssRNA) governing 5-HT production. Intestinal epithelium-specific deletion of mouse Piezo1 profoundly disturbed gut peristalsis, impeded experimental colitis, and suppressed serum 5-HT levels. Because of systemic 5-HT deficiency, conditional knockout of Piezo1 increased bone formation.
=== Pneumatic tube systems in hospitals === Hospitals deploy PTS as part of broader automation strategies to handle rising patient volumes and throughput pressures in many settings, particularly those with aging populations and high admission rates. International indicators show heterogeneous trends—discharges fell in many OECD countries between 2011 and 2019, but rose substantially in others (e.g., Korea and Japan), and increased in large partner countries such as China—illustrating why capacity solutions like PTS are adopted to alleviate internal logistics bottlenecks.
== Applications == Mass spectrometry imaging (MSI) can be used to map the spatial distribution of biomolecules in tissue without prior labeling of specific targets. It is used in clinical pharmacological research to examine changes in proteins, lipids and metabolites associated with the disease. Applications include biomarker identification, cancer research, studies of treatment response and evaluation of drug-delivery methods. Ion colocalization has been studied as a way to infer local interactions between biomolecules. Similarly to colocalization in microscopy imaging, correlation has been used to quantify the similarity between ion images and generate network models.
=== Pharmacodynamics === NBOMe-LAD is known to act as an agonist of the serotonin 5-HT2A receptor and to interact with other receptors, but shows dramatically reduced potency compared to LSD in vitro. At the serotonin 5-HT2A receptor, it had 37-fold lower affinity, 148-fold lower activational potency in terms of calcium release, and around half the maximal efficacy in terms of calcium release relative to LSD. On the other hand, NBOMe-LAD had only about 4-fold lower potency in terms of β-arrestin recruitment along with similar activational efficacy for this pathway relative to LSD. NBOMe-LAD produces the head-twitch response, a behavioral proxy of psychedelic effects, in rodents, but with greatly reduced potency and maximal efficacy relative to PRO-LAD and analogues. Its ED50Tooltip median effective dose for inducing the head-twitch response was 13-fold lower than that of PRO-LAD and its maximal effect was about one-third that of PRO-LAD. However, the most efficacious dose of NBOMe-LAD was 3.2 mg/kg whereas that of PRO-LAD was 1 mg/kg.
==== Animal production ==== The tendency toward fewer and larger farms has been accompanied by an increase in animal production, using fewer resources per produced unit. The number of dairy farmers has reduced to about 3,800 with an average herd size of 150 cows. The milk quota is 1,142 tonnes. More than half of the cows live in new loose-housing systems. Export of dairy products accounts for more than 20 percent of the total Danish agricultural export. The total number of cattle in 2011 was approximately 1.5 million. Of these, 565,000 were dairy cows and 99,000 were suckler cows. The yearly number of slaughtering of beef cattle is around 550,000. For more than 100 years the production of pigs and pig meat was a major source of income in Denmark. Approximately 90 percent of the production is exported. This accounts for almost half of all agricultural exports and for around 5 percent of Denmark's total exports. About 4,200 farmers produce 28 million pigs annually. Of these, 20.9 million are slaughtered in Denmark. Fur animal production on an industrial scale started in the 1930s in Denmark. Prior to a government-mandated culling during the COVID-19 pandemic, Denmark was the world's largest producer of mink furs, with 1,400 mink farmers fostering 17.2 million mink and producing around 14 million furs of the highest quality every year (see mink industry in Denmark). Approximately 98 percent of the skins sold at Kopenhagen Fur Auction were exported. Fur ranked as Danish agriculture's third largest export article, at more than DKK 7 billion annually.
Sources: en.wikipedia.org
Free nerve ending A type of unencapsulated nerve ending that detects pain, temperature, and crude touch. These are the most common type of cutaneous receptors. Frontal lobe A region of the cerebral cortex involved in decision-making, planning, motor function, problem-solving, and aspects of personality. Located at the front of each cerebral hemisphere. Frontal eye fields A region in the frontal lobe involved in voluntary eye movements and visual attention. It plays a role in saccadic control and visual tracking. Functional connectivity A measure of how different brain regions interact during rest or tasks, often assessed using fMRI or EEG by examining correlations in activity over time. Functional magnetic resonance imaging (fMRI) A neuroimaging technique that measures brain activity by detecting changes in blood oxygenation (BOLD signal). It is used to study brain function in real time. Fusiform gyrus A brain region located in the temporal and occipital lobes involved in high-level visual processing, including facial recognition and object categorization. Fusiform face area (FFA) A specialized part of the fusiform gyrus that responds selectively to faces. It is often studied in the context of prosopagnosia (face blindness) and visual expertise.
=== Governmental districts (Regierungsbezirke) === The large states of Baden-Württemberg, Bavaria, Hesse, and North Rhine-Westphalia are divided into governmental districts, or Regierungsbezirke. In Rhineland-Palatinate, these districts were abolished or re-organized on 1 January 2000, in Saxony-Anhalt on 1 January 2004, and in Lower Saxony on 1 January 2005. From 1990 until 2012, Saxony was divided into three districts (called Direktionsbezirke since 2008). In 2012, these districts' authorities were merged into one central authority, the Landesdirektion Sachsen.
== Epidemiology == Kwashiorkor is rare in high-income countries. It is mostly observed in low-income and middle-income nations and regions such as Southeast Asia, Central America, Congo, Ethiopia, Puerto Rico, Jamaica, South Africa, and Uganda, where poverty is prominent. Occurrences of severe malnutrition also tend to trend higher under conditions of food insecurity, higher prevalence of infectious diseases, lack of access to appropriate care, and poor living situations with inadequate sanitation. Communities experiencing famine are affected the most, especially during the rainy season. Prevalence varies, but it affects children of either sex commonly under five years old. "Globally, kwashiorkor indirected accounted for 53% of deaths among children under five between 2000 and 2003 when associated with other common childhood diseases like acute respiratory infections, malaria, measles, HIV/AIDS and other causes of perinatal deaths." When compared to marasmus in developing countries, kwashiorkor typically has a lower prevalence, "0.2%-1.6% for kwashiorkor and 1.2%-6.8% for marasmus." Factors such as "diet, geographical locations, climate, and aflatoxin exposure" have been invoked as potential causes for observed differences in the prevalence of kwashiorkor and marasmus. In general, in areas where Severe Acute Malnutrition (SAM) is prevalent, marasmus is more often the dominant SAM condition. However, in certain areas, kwashiorkor may be more common than marasmus.
Melatonin, the hormone produced in the pineal gland in the brain and secreted in dim light and darkness, among its other functions, promotes sleep in diurnal mammals. It activates the melatonin MT1 and MT2 receptors to produce beneficial effects on sleep, therefore being used exogenously for mild insomnia. A small improvement in sleep onset and total sleep time by using melatonin has been shown in recent systematic reviews. Synthetic analogues of melatonin, or melatonin receptor agonists, have also been made. Among these, ramelteon and tasimelteon are used for sleep disorders. Agomelatine is an antidepressant of this class, with some studies also reporting an effect on sleep.
Sources: en.wikipedia.org
A sealed container kept at room temperature and away from moisture is typical. Heat and humidity promote conversion to creatinine and can reduce assay values. Long-term storage under dry conditions helps maintain the original crystalline form.
Creatinine is a degradation product formed when creatine loses water and cyclizes. It can appear during storage, processing, or analysis if conditions are harsh. Quality specifications often set a maximum limit for creatinine to control purity.
No universal testing protocol applies across all markets. Some products follow pharmacopeial monographs, while others rely on manufacturer specifications and third-party certificates. Common tests include assay, water content, heavy metals, and microbial limits.
A sealed container at room temperature, away from moisture and direct heat, is suitable for most solid material. Keeping the lid closed limits water uptake and caking. Long-term storage in a refrigerator is not necessary if the powder remains dry.