This is a working overview of HPLC-UV, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2025-08-21. Anything still debated is marked as such rather than presented as settled.
Recommended storage usually involves a sealed container kept at room temperature, away from direct sunlight and moisture. High humidity can cause caking, which changes flow properties and may complicate accurate weighing. Repeated opening of containers exposes the powder to air and moisture, so smaller aliquots can reduce handling effects. Storage temperature ranges are not absolute requirements; they reflect conditions that slow degradation and preserve consistent physical characteristics. Clean, dry tools help prevent contamination during sampling.
Identity and purity are commonly assessed by high-performance liquid chromatography, often with ultraviolet detection, and by spectroscopic techniques such as infrared or nuclear magnetic resonance. These methods can distinguish creatine from creatinine and detect related impurities. Moisture content may be measured by Karl Fischer titration or loss on drying. Particle size, bulk density, and heavy metal limits are additional quality parameters. Not every product is tested by every method, so specifications depend on the intended use and regulatory framework.
Solid creatine monohydrate is generally stable when kept dry and protected from extremes of heat and humidity. In the presence of moisture, it can gradually convert to creatinine, a cyclic dehydration product that has little value for phosphocreatine synthesis. Elevated temperatures and acidic conditions accelerate this conversion in solution. Because the reaction is slow in cool, dry storage, typical shelf lives are measured in years rather than weeks. Packaging that limits moisture and oxygen exposure helps maintain purity.
Commercial creatine products appear in several forms, including monohydrate, hydrochloride, citrate, nitrate, and ethyl ester. Creatine monohydrate is the most studied form and serves as a reference material in comparative research. Different forms vary in solubility, pH, and water content, but they share creatine as the active moiety after dissolution. Claims that one form is uniformly superior remain debated, and study designs often differ in population, exercise protocol, and outcome measures. Purity and hydration state are central to interpreting product labels.
Creatine monohydrate is the hydrated form of creatine, a nitrogen-containing organic acid involved in cellular energy transfer. Its molecular formula is C4H11N3O3, and it consists of creatine plus one water molecule in the crystal lattice. The anhydrous base, creatine, has the formula C4H9N3O2. The compound appears as a white, odorless, crystalline powder and is classified as a guanidine derivative. It is distinct from creatinine, a breakdown product measured in clinical chemistry.
| Property | Value | Notes |
|---|---|---|
| Typical storage temperature | 15–25 °C | Cool, dry, sealed conditions slow conversion to creatinine. |
| Moisture sensitivity | Moderate | Absorbs water from humid air, which can cause caking. |
| Primary purity method | HPLC-UV | Separates creatine from creatinine and related impurities. |
| Moisture method | Karl Fischer titration | Measures water content; loss on drying is an alternative. |
| Degradation product | Creatinine | Forms by dehydration, especially in solution or humid heat. |
==== Human papillomavirus ==== Human papillomavirus (HPV) is the most commonly transmitted sexually transmitted infection, affecting both men and women. While most infections are asymptomatic and are cleared by the immune system, some types of the virus cause genital warts, and other types, if untreated, cause various forms of cancer, including cervical cancer and penile cancer. Genital warts and cervical cancer are the two most common problems resulting from HPV. Circumcision is associated with a reduced prevalence of oncogenic types of HPV infection, meaning that a randomly selected circumcised man is less likely to be infected with cancer-causing types of HPV than an uncircumcised man. It also decreases the likelihood of multiple infections. As of 2012, there was no strong evidence that it reduces the rate of new HPV infection, but the procedure is associated with increased clearance of the virus by the body, which can account for the finding of reduced prevalence. HPV vaccination is the best method to prevent infection from HPV. Although genital warts are caused by a type of HPV, there is no statistically significant relationship between being circumcised and the presence of genital warts.
Haemovigilance – incident management, investigation, follow-up, and reporting Risk management including writing, implementing, updating and monitoring local policies and procedures Blood management education Monitoring and providing feedback on activities related to compliance with best practice guidelines including auditing Change management activities Appropriate use and management including waste minimisation Assisting with the implementation of PBM strategies
=== Warfare and weapons === At RAF Bomber Command, Dyson and colleagues proposed removing two gun turrets from Avro Lancaster bombers, to cut the catastrophic losses due to German fighters in the Battle of Berlin. A Lancaster without turrets could fly 50 mph (80 km/h) faster and be much more manoeuvrable.
On April 21, 2009, Newsom announced his candidacy for governor of California in the 2010 election. He named state senator (and future U.S. senator) Alex Padilla to chair his campaign. He received former president Bill Clinton's endorsement in September. Throughout the campaign, he had low poll numbers, trailing Democratic frontrunner Jerry Brown by more than 20 points in most polls. Newsom dropped out of the race in October and ran for lieutenant governor instead.
=== Therapeutic evaluation === Several investigations correlate the Bristol stool scale in response to medications or therapies, in fact, in one study was also used to titrate the dose more finely than one drug (colestyramine) in subjects with diarrhoea and faecal incontinence. In a randomised controlled study, the scale was used to study the response to two laxatives: Macrogol (polyethylene glycol) and psyllium (Plantago psyllium and other species of the same genus) of 126 male and female patients for a period of 2 weeks of treatment; failing to show the most rapid response and increased efficiency of the former over the latter. The primary outcomes were the number of weekly bowel movements, stool consistency according to the Bristol stool scale, time to defecation, overall effectiveness, difficulty in defecating, and stool consistency. From 2010, several studies have used the scale as a diagnostic tool validated for recognition and evaluation of response to various treatments, such as probiotics, moxicombustion, laxatives in the elderly, preparing Ayurvedic poly-phytotherapy filed TLPL/AY, psyllium, mesalazine, methylnaltrexone, and oxycodone/naloxone, or to assess the response to physical activity in athletes.
Sources: en.wikipedia.org
== Side effects and overdose == Side effects from intra-articular administration can include joint pain, swelling, lameness, and, rarely, infection of the joint. Intramuscular injection can cause dose-dependent inflammation and bleeding, since PSGAG is an analogue of the anticoagulant heparin. In dogs, this may manifest as bleeding from the nose or as bloody stools. The increased risk of bleeding has some advising not to give PSGAG to animals with bleeding disorders, though its only absolute contraindication is hypersensitivity to PSAGs when it is being given intra-articularily. Overdose on PSGAG is quite rare, as the LD50 is over 1000 mg/kg when given intravenously to dogs. Signs of overdose include exacerbated side effects such as joint pain, swelling, and lameness. When dogs received three times the normal dose intramuscularly twice a week for 13 weeks, they had increased liver and kidney weight, as well as microscopic lesions on the liver, kidneys, and lymph nodes. At 11 times the normal dose, they also had increased alanine transferase, cholesterol, and prothrombin time (i.e. coagulation via the extrinsic pathway took longer), and fewer platelets.
=== PlayStation 3 version === While the Windows and Xbox 360 versions of The Orange Box were developed and published by Valve, the development of the PlayStation 3 port was outsourced to the Electronic Arts studio EA UK. In an interview with Edge magazine before the game's release, Valve co-founder Gabe Newell commented, "I think the people who have The Orange Box on the PS3 are going to be happy with their game experience. We've done the PC and 360 versions here and EA has a team doing the PS3 version – and they'll make the PS3 version a good product; EA got the job done in putting a lot of people with PS3 experience on the project. But I think it's harder to get it to the same standard as the 360 and PC versions". Despite this, he noted that Valve will probably handle PlayStation 3 versions of its products in the future.
== External links == The MEROPS online database for peptidases and their inhibitors: M13.001 Archived 2019-09-12 at the Wayback Machine Neprilysin at the U.S. National Library of Medicine Medical Subject Headings (MeSH) Overview of all the structural information available in the PDB for UniProt: P08473 (Neprilysin) at the PDBe-KB. This article incorporates text from the United States National Library of Medicine, which is in the public domain.
In the Bronze Age, the Hellenes had trade and cultural contacts with Egypt. Before the time that Alexander the Great occupied Egypt, the Greek name, sphinx, was already applied to these statues. The historians and geographers of Greece such as Herodotus wrote extensively about Egyptian culture. There was a single sphinx in Greek mythology, a unique demon of destruction and bad luck. Apollodorus describes the sphinx as having a woman's face, the body and tail of a lion and the wings of a bird. Pliny the Elder mentions that Ethiopia produces plenty of sphinxes, with brown hair and breasts, corroborated by 20th-century archeologists. Statius describes her as a winged monster, with pallid cheeks, eyes tainted with corruption, plumes clotted with gore and talons on livid hands. John Tzetzes described her as having the front of a lion, the rear of a human, the wings of a griffin and the claws of an eagle. Sometimes, the wings are specified to be those of an eagle, and the tail to be serpent-headed. According to Hesiod, the Sphinx was a daughter of Orthrus and an unknown she—either the Chimera, Echidna, or Ceto. According to Apollodorus and Lasus, she was a daughter of Echidna and Typhon. The sphinx was the emblem of the ancient city-state of Chios, and appeared on seals and the obverse side of coins from the 6th century BC until the 3rd century AD.
== Etymology == The nomenclature for the Do6a venom peptide splits into two components: "Do" refers to the specific Velvet ant species it is extracted from: the Dasymutilla occidentalis. "6a" refers to the specific family and isoform of the Do peptide. Other venom peptides originating from different velvet ant species exist that follow similar nomenclature, such as Dk5a in Dasymutilla klugii.
Sources: en.wikipedia.org
Solid product can remain within specification for years when stored dry and sealed, but expiration dates reflect manufacturer testing and regulatory conventions. Moisture and heat increase conversion to creatinine, so storage conditions matter more than the printed date alone. Degradation is gradual and can be monitored by purity testing.
Purity is typically evaluated by chromatographic separation with ultraviolet detection, sometimes supported by spectroscopic identity tests. Moisture and creatinine content are common quality parameters. Results depend on the analytical method, sample preparation, and specification limits.
Clumping occurs when powder absorbs moisture, causing particles to stick together. Humidity, temperature changes, and repeated container opening promote this effect. Clumps do not necessarily indicate chemical degradation, but they can affect weighing and mixing.
Creatine is the base compound, while creatine monohydrate includes one water molecule per creatine molecule in its crystal structure. The monohydrate form is common in supplements and analytical standards. The body uses creatine itself after the water is removed or dissociated.