HPLC comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Last reviewed on 2026-02-24. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
In the body, creatine is obtained from dietary meat and fish and is also synthesized from arginine, glycine, and methionine. Muscle stores creatine and phosphocreatine, which participate in the rapid regeneration of adenosine triphosphate during short, intense activity. The monohydrate form is used in research because it is chemically defined, stable as a dry solid, and relatively inexpensive to produce. Questions remain about whether other creatine forms offer meaningful advantages in absorption or tissue retention, and findings vary across studies and populations.
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 includes one water molecule per creatine molecule |
| Molar mass | 149.15 g/mol | Value for the monohydrate; anhydrous creatine is about 131.13 g/mol |
| Appearance | White crystalline powder | Odorless or nearly odorless in purified form |
| Solubility in water | About 13 g/L at 25 °C | Solubility increases with temperature and varies with pH |
| Common synonyms | Creatine hydrate; N-(aminoiminomethyl)-N-methylglycine | Monohydrate distinguishes it from anhydrous creatine |
Quality control for creatine monohydrate typically combines identity, assay, and impurity tests. High-performance liquid chromatography with ultraviolet detection is common for separating creatine from creatinine and related substances. Nuclear magnetic resonance and infrared spectroscopy can confirm molecular structure, while titration may assess acid-base content. Moisture content, heavy metals, residual solvents, and microbial limits are checked according to applicable standards. These tests help distinguish compliant material from powders that have degraded, been diluted, or contain manufacturing residues.
Handling practices aim to limit moisture uptake and thermal exposure. Containers should stay closed when not in use, and storage areas should avoid direct sunlight, strong heat, and high humidity. Caking can occur when powder absorbs water, even if the creatine itself has not fully degraded. Aqueous stock solutions are best prepared fresh when needed because they are less stable than the solid. Open questions include how different excipients, packaging materials, and climate conditions affect long-term stability across global supply chains.
ATC code A10 Drugs used in diabetes is a therapeutic subgroup of the Anatomical Therapeutic Chemical Classification System, a system of alphanumeric codes developed by the World Health Organization (WHO) for the classification of drugs and other medical products. Subgroup A10 is part of the anatomical group A Alimentary tract and metabolism. Codes for veterinary use (ATCvet codes) can be created by placing the letter Q in front of the human ATC code: for example, QA10. National versions of the ATC classification may include additional codes not present in this list, which follows the WHO version. A10AB01 Insulin (human) A10AB02 Insulin (beef) A10AB03 Insulin (pork) A10AB04 Insulin lispro A10AB05 Insulin aspart A10AB06 Insulin glulisine A10AB30 Combinations === A10AC Insulins and analogues for injection, intermediate-acting === A10AC01 Insulin (human) A10AC02 Insulin (beef) A10AC03 Insulin (pork) A10AC04 Insulin lispro A10AC30 Combinations
If analytes are too small to generate a readable signal for determining concentration, the assay matrix can be modified. CD/DVD based assays utilize the optical properties of gold. Gold nanoparticle bioconjugates are tracers used to increase the sensitivity of the assay. The gold nanoparticles can be identified with photometric or plasmonic detectors. The smaller the nanoparticles are, the more sensitive the assay becomes. Silver enhancer solution is also used to increase the reflective properties of samples. Gold nanoparticles have catalytic properties which cause them to reduce silver ions to silver metal. The silver metal deposits on the analytes and causes signals to be amplified. Silver metal is more easily detectable by cameras, scanners, or other drives than is the analyte alone. Still, this enhancement procedure requires many additional reaction and washing steps which could lead to analytical errors.
12(S)-HpETE and 12(S)-HETE induce itching responses when injected into the skin of mice; this has led to the suggestion that these metabolites contribute to the itching (i.e. clinical pruritus) which accompanies such conditions as atopic dermatitis, contact dermatitis, urticaria, chronic renal failure, and cholestasis. Since it mediates 12(S)-HETE-induced itching in the mouse model, BLT2 rather than GPR31 may mediate human itch in these reactions.
Sources: en.wikipedia.org
==== Injectable glucagon-like peptide analogs and agonists ==== Glucagon-like peptide (GLP) agonists bind to a membrane GLP receptor. As a consequence, insulin release from the pancreatic beta cells is increased. Endogenous GLP has a half-life of only a few minutes, thus an analogue of GLP would not be practical. As of 2019, the AACE lists GLP-1 agonists, along with SGLT2 inhibitors, as the most preferred anti-diabetic agents after metformin. Liraglutide in particular may be considered first-line in diabetic patients with cardiovascular disease, as it has received FDA approval for reduction of risk of major adverse cardiovascular events in patients with type 2 diabetes. In a 2011 Cochrane review, GLP-1 agonists showed approximately a 1% reduction in HbA1c when compared to placebo. GLP-1 agonists also show improvement of beta-cell function, but this effect does not last after treatment is stopped. Due to shorter duration of studies, this review did not allow for long-term positive or negative effects to be assessed.
==== Marsupials ==== Order Didelphimorphia Family Didelphidae (opossums) Monodelphis domestica, gray short-tailed opossum (2007) Order Dasyuromorphia Family Dasyuridae Antechinus stuartii, brown antechinus (2020) Sarcophilus harrisii, Tasmanian devil () Sminthopsis crassicaudata, fat-tailed dunnart (ongoing) Dasyurus hallucatus, northern quoll (ongoing) Family Myrmecobiidae Myrmecobius fasciatus, numbat (ongoing) † Family Thylacinidae † Thylacinus cynocephalus, thylacine () Order Peramelemorphia Family Peramelidae Perameles gunnii, eastern barred bandicoot (ongoing) Family Thylacomyidae Macrotis lagotis, greater bilby (ongoing) Order Notoryctemorphia, Family Notoryctidae Notoryctes typhlops, southern marsupial mole (ongoing) Order Diprotodontia Family Macropodidae Macropus eugenii, tammar wallaby (2011) Petrogale penicillata, brush-tailed rock-wallaby (ongoing) Family Potoroidae Bettongia gaimardi, eastern bettong (ongoing) Bettongia penicillata ogilbyi, woylie (2021) Family Petauridae Gymnobelideus leadbeateri, Leadbeater's possum (ongoing) Family Burramyidae Burramys parvus, mountain pygmy possum (ongoing) Family Vombatidae Vombatus ursinus, common wombat (ongoing) Family Phascolarctidae Phascolarctos cinereus, koala (2013 draft)
Blast cell Blast cells are very immature cells that are normally found in the bone marrow, where they develop into mature cells (hematopoiesis) before being released into the blood. They can be identified by their large overall size, deep blue cytoplasm, and large nucleus with fine chromatin and prominent nucleoli. When seen on the blood smear, blast cells are an abnormal finding and may be indicative of acute leukaemia or other serious blood disorders. Rarely, they may be seen in severe cases of left shift. The presence of Auer rods inside blast cells indicates that they are of myeloid origin, which has important implications for leukaemia treatment. Other morphologic features can provide information about the lineage of blast cells: for example, myeloblasts tend to be large with distinct nucleoli, while lymphoblasts can be smaller with a denser chromatin pattern. However, these features are not diagnostic, and flow cytometry or special staining is generally used to confirm the lineage.
Isobutyrylfentanyl is an opioid analgesic that is an analog of fentanyl and has been sold online as a designer drug. It is believed to be around the same potency as butyrfentanyl but has been less widely distributed on illicit markets, though it was one of the earliest of the "new wave" of fentanyl derivatives to appear, and was reported in Europe for the first time in December 2012.
Sources: en.wikipedia.org
The only people allowed in the forests are firefighters and people who own property in the forests. 2021 Atlantic hurricane season – Thirteen people are killed in Alabama during Tropical Storm Claudette. Ten of the victims die in a single car crash, nine of whom are children. An EF3 tornado strikes the Illinois cities of Naperville, Woodridge, and Darien, destroying 12 homes, damaging an additional 100, and injuring six people. June 21 Las Vegas Raiders defensive end Carl Nassib becomes the first National Football League player to come out as openly gay. Minnesota Vikings defensive tackle Jaylen Twyman is shot along with three others while visiting his aunt in Washington, D.C. June 22 2021 New York City mayoral election – Residents of New York City elect a new mayor. This is the first time that a New York City election is determined using rank-choice (instant-runoff) voting. 2021 Buffalo mayoral election – Community activist and self-avowed socialist India Walton defeats incumbent mayor Byron Brown to win the Democratic primary. As the Democratic candidate is overwhelmingly favored to win the mayoralship in November, this will possibly be the first time that a socialist will be mayor of a major American city since 1960. COVID-19 pandemic: Michigan lifts its face mask requirements and capacity restrictions on indoor events. Masks are still required for nursing homes, prisons, hospitals, schools, funeral directors, and agricultural workers. Usage at businesses is optional.
=== Research === Similar assays can be performed for research purposes, detecting concentrations of potential clinical candidates like anti-fungal and asthma drugs. This technique is obviously useful in observing multiple species in collected samples, as well, but requires the use of standard solutions when information about species identity is sought out. It is used as a method to confirm results of synthesis reactions, as purity is essential in this type of research. However, mass spectrometry is still the more reliable way to identify species.
PIHCA, due to this slight advantage, is currently undergoing phase III clinical trials for transporting the drug doxorubicin as a treatment for hepatocellular carcinomas. Coating these polymeric nanoparticle devices with different surfactants can also aid BBB crossing and uptake in the brain. Surfactants such as polysorbate 80, 20, 40, 60, and poloxamer 188, demonstrated positive drug delivery through the blood–brain barrier, whereas other surfactants did not yield the same results. It has also been shown that functionalizing the surface of nanoparticles with polyethylene glycol (PEG), can induce the "stealth effect", allowing the drug-loaded nanoparticle to circulate throughout the body for prolonged periods of time. Further, the stealth effect, caused in part by the hydrophilic and flexible properties of the PEG chains, facilitates an increase in localizing the drug at target sites in tissues and organs.
Sources: en.wikipedia.org
It is a crystalline form of creatine that contains one water molecule per creatine molecule. The compound occurs naturally in muscle tissue and is also produced synthetically for research and consumer products. The monohydrate label describes the solid's hydration state.
Creatine monohydrate contains creatine, but the two terms are not strictly interchangeable. The monohydrate includes water in the crystal, while creatine refers to the base molecule. Other creatine forms pair the molecule with different acids or carriers.
Dietary creatine is found mainly in meat and fish. The human body also synthesizes creatine from amino acids in the liver, kidneys, and pancreas. The monohydrate powder used in products is manufactured rather than extracted directly from food.
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.