A practical reference on Certificate of analysis: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-07-28. Anything still debated is marked as such rather than presented as settled.
Stability depends heavily on physical state. Lyophilized powder held dry, cold and dark retains its content over long periods, whereas dissolved peptide begins to change within days at room temperature. The most cited degradation route is oxidation of the methionine residue, which converts the peptide to a sulfoxide form that elutes differently on chromatography. Hydrolysis of amide bonds and adsorption onto container walls contribute smaller losses. Buffers that exclude oxygen from the headspace slow the oxidation pathway, but no single condition prevents all change indefinitely.
Practical handling follows from those properties. Bulk material is best divided into single-use portions soon after receipt, because each thaw exposes the whole container to moisture and temperature cycling. Vials should be allowed to reach room temperature before opening to prevent condensation on the powder. Low-binding plasticware reduces loss of dilute solutions, and sterile filtration is used when a preparation must remain free of microbial growth. Records of batch number, reconstitution date and storage history are what allow a later analytical result to be interpreted meaningfully.
Identity and purity of semax are established with reversed-phase high-performance liquid chromatography coupled to ultraviolet detection, usually at 214 nanometres. Mass spectrometry, most often electrospray ionisation in positive mode, confirms the molecular mass and reveals truncated sequences. Amino acid analysis and peptide mapping after enzymatic digestion provide additional structural confirmation. Laboratories typically report purity as the percentage area of the main peak, a figure that does not capture isomeric or oxidised variants unless the method resolves them.
The peptide is prone to several degradation pathways. Oxidation of the methionine residue produces a sulfoxide that elutes close to the parent peak in many chromatographic systems. Hydrolysis of peptide bonds and deamidation of susceptible residues in related sequences also reduce purity over time. Lyophilised material kept dry at minus twenty degrees Celsius and shielded from light is the most stable form commonly described in laboratory practice.
| Property | Value | Notes |
|---|---|---|
| Typical purity specification | ≥ 95 % of peak area by HPLC | Some suppliers quote 98 % or higher |
| Identity confirmation | Mass spectrometry (electrospray or MALDI) | Observed mass is compared with the calculated mass |
| Common analytical method | Reversed-phase HPLC on a C18 column | Acetonitrile and water gradients with trifluoroacetic acid |
| Primary degradation route | Oxidation of the methionine residue | Yields a sulfoxide that separates cleanly on chromatography |
| Storage of dissolved material | Aliquoted and frozen at −20 °C or below | Single-use aliquots avoid repeated temperature cycling |
Published studies examine a fairly narrow set of endpoints. Rodent experiments commonly measure maze learning, infarct volume after induced ischemia, and tissue levels of neurotrophic factors. Clinical reports from Russian centres describe attention, memory and recovery scores in patients after stroke or transient ischemic attack. Most of those human studies are small and few have been repeated by independent groups. Outcome measures differ between studies, which limits direct comparison.
Circulation time for the peptide is short because peptidases cleave it readily. The Pro-Gly-Pro tail is thought to slow breakdown compared with the bare ACTH fragment, but the gain appears modest. Absorption after intranasal dosing is limited, and only a fraction of a dose is expected to reach the central nervous system. Laboratory concentrations therefore sit well above levels achieved systemically, a gap that complicates translation from bench findings to clinical claims.
The mechanisms attributed to semax are inferred from animal and cell studies rather than traced to one confirmed target. The most frequently cited pathway involves increased expression of brain-derived neurotrophic factor and nerve growth factor in hippocampal and cortical tissue. Some work points to engagement of melanocortin receptors, particularly MC4, which the parent ACTH fragment can activate. Effects on dopaminergic and serotonergic signalling have also been reported. No single account explains all observed results, and the relative weight of each pathway remains unsettled.
Semax is normally supplied as a lyophilized powder, and that form is the most stable. Suppliers commonly recommend storage at -20 °C in a desiccated container protected from light, with short-term handling at room temperature limited to weighing and transfer. Powder that has absorbed moisture degrades faster, so vials should be warmed to ambient temperature before opening to prevent condensation on the contents. Hygroscopic behavior is typical of short hydrophilic peptides, and humidity control matters more than temperature alone for long-term retention.
Once dissolved, the peptide is considerably less stable than the solid. Aqueous solutions are usually prepared at neutral to slightly acidic pH, filtered, and divided into single-use aliquots before freezing. Repeated freeze-thaw cycles are a common cause of avoidable loss and are best prevented by never refreezing a thawed aliquot. Adsorption to plastic and glass surfaces can lower the measured concentration of dilute solutions, particularly below roughly 0.1 mg/mL. Buffer choice, salt content, and container material all influence how much peptide remains detectable after storage.
Identity and purity are established with standard peptide methods. Reversed-phase HPLC with ultraviolet detection near 214 nm resolves the parent peak from deletion and truncation byproducts, and reports typically quote a main-peak percentage. Mass spectrometry by electrospray or MALDI-TOF confirms the expected molecular mass, while amino acid analysis or peptide mapping can verify composition when the sequence itself is in question. A certificate of analysis that pairs a chromatogram with a mass spectrum is more informative than a purity figure alone. Counter-ion content and residual solvents are separate specifications and are frequently omitted.
== Medical uses == Tafasitamab, in combination with lenalidomide, is indicated for the treatment of adults with relapsed or refractory diffuse large B-cell lymphoma. In the EU, tafasitamab (Minjuvi) is indicated in combination with lenalidomide followed by tafasitamab monotherapy for the treatment of adults with relapsed or refractory diffuse large B-cell lymphoma who are not eligible for autologous stem cell transplant. In June 2025, the US Food and Drug Administration (FDA) expanded the indication for tafasitamab, in combination with lenalidomide and rituximab, for adults with relapsed or refractory follicular lymphoma.
=== Liver injury === Methimazole is commonly associated with transient, mild, asymptomatic elevations in serum aminotransferase levels, typically during the first months of treatment with a high dose. More serious liver injury can, usually with a cholestatic or mixed pattern of enzyme elevations and prolonged cholestatic hepatitis. Methimazole induced liver injury fatalities are rare and symptoms and jaundice usually clear within 2-8 weeks of stopping the drug. In most cases switching to propylthiouracil does not result in a recurrence of liver injury. To differentiate methimazole induced liver injury from liver injury related to the underlying hyperthyroidism, it is recommended to check baseline liver enzymes prior to initiation of treatment. Other known side effects include:
== Fuels and consumption == Ashing is a test to deduce the amount of ash forming material present in a petroleum product so as to decide its use in certain applications. Ash-forming materials are considered to be undesirable impurities or contaminants. In the ash analysis of petroleum products, ash content represents the incombustible component remaining after a sample of the furnace oil is completely burned. The ash content of petroleum products is generally low. It is defined as the inorganic residue that remains after combustion of the oil in air at specific high temperature. Ash typically ranges from 0.1 to 0.2% in oil. Some of the ash forming constituents occur naturally in crude oil; others are present as a result of refining or contamination during storage or distribution. Knowledge of the amount of ash-forming material present in a product can provide information as to whether or not the product is suitable application. In the ash analysis of coal and other solid fuels, the amount of sulfur retained in the ash during the ashing process is not constant, but rather is dependent upon the conditions of ashing as well as the other inorganic constituents in the ash that may form sulfates during the ashing procedure. As such, different ashing procedures may yield different ash contents.
Sources: en.wikipedia.org
=== North America === Accium BioSciences at Swedish Medical Center Cherry Hill, Seattle, WA André E. Lalonde Accelerator Mass Spectrometry Laboratory (AEL AMS) at the University of Ottawa in Ottawa, Canada Beta Analytic Accelerator Mass Spectrometry Facility in Miami, Florida Center for Accelerator Mass Spectrometry (CAMS) at the Lawrence Livermore National Laboratory Center for Applied Isotope Studies (CAIS) at University of Georgia. DirectAMS (D-AMS) radiocarbon labs in Bothell, WA & Seattle, WA Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan Institute for Structure and Nuclear Astrophysics, The University of Notre Dame, Notre Dame, Indiana Institute of Energy and the Environment Radiocarbon Laboratory at the Pennsylvania State University, University Park, Pennsylvania MegaSIMS at the University of California, Los Angeles in Los Angeles, CA National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS) Facility at Woods Hole Oceanographic Institution NSF - Arizona Accelerator Mass Spectrometry (AMS) Laboratory Pharmaron ABS, Inc. in Germantown, Maryland Purdue Rare Isotope Measurement Laboratory at Purdue University in West Lafayette, Indiana Trace Element Accelerator Mass Spectrometer (TEAMS) at the Naval Research Laboratory in Washington, DC W.M. Keck Carbon Cycle Accelerator Mass Spectrometry (KCCAMS) Facility at the University of California, Irvine
Nicergoline, sold under the brand name Sermion among others, is an ergot derivative used to treat senile dementia and other disorders with vascular origins. Internationally it has been used for frontotemporal dementia as well as early onset in Lewy body dementia and Parkinson's dementia. It decreases vascular resistance and increases arterial blood flow in the brain, improving the utilization of oxygen and glucose by brain cells. It has similar vasoactive properties in other areas of the body, particularly the lungs. Unlike many other ergolines, such as ergotamine, nicergoline is not associated with cardiac fibrosis. It is used for vascular disorders such as cerebral thrombosis and atherosclerosis, arterial blockages in the limbs, Raynaud's disease, vascular migraines, and retinopathy. Nicergoline has been registered in over fifty countries and has been used for more than three decades for the treatment of cognitive, affective, and behavioral disorders of older people.
==== Sexual misconduct and resignation ==== A $279,000 payoff for the silence of Jessica Hahn, who alleged that Bakker and former PTL Club co-host John Wesley Fletcher drugged and raped her, was paid with PTL funds through Bakker's associate Roe Messner. Bakker, who made PTL's financial decisions, allegedly kept two sets of books to conceal accounting irregularities. Reporters for The Charlotte Observer, led by Charles Shepard, investigated PTL's finances and published a series of articles. On March 19, 1987, after the disclosure of a payoff to Hahn, Bakker resigned from PTL. Although he acknowledged that he had a sexual encounter with Hahn at a hotel room in Clearwater, Florida, he denied raping her. Bakker was also the subject of homosexual and bisexual allegations made by Fletcher and PTL director Jay Babcock, which Bakker denied under oath. Rival televangelist John Ankerberg appeared on Larry King Live and made several allegations of moral impropriety against Bakker, which both Bakkers denied. Bakker was succeeded as PTL head by the Rev. Jerry Falwell of Thomas Road Baptist Church in Lynchburg, Virginia. Bakker chose Falwell as his successor because he feared that fellow televangelist Jimmy Swaggart, who had initiated an Assemblies of God investigation into Bakker's sexual misconduct, was attempting to take over his ministry. Bakker believed that Falwell would temporarily lead the ministry until the scandal died down, but on April 28, 1987, Falwell barred Bakker from returning to PTL.
On April 1, 2008, Pizza Hut in America sent emails to customers advertising their pasta items. The email (and similar advertising on the company's website) stated: "Pasta so good, we changed our name to Pasta Hut!" The name change was a publicity stunt held on April Fools' Day, extending through the month of April, with the company's Dallas headquarters changing its exterior logo to Pasta Hut. This name change was also used to promote the new Tuscani Pasta line and the new Pizza Hut dine-in menu. The first Pasta Hut advertisement showed the original Pizza Hut restaurant being imploded and re-created with a "Pasta Hut" sign. A version of this stunt was re-created by Pizza Hut's UK operation later that year in October 2008, which included ten locations in London temporarily taking on new "Pasta Hut" signage. Pizza Hut UK's chief executive at the time has insisted that this was solely intended as a "PR exercise" and the chain never planned on permanently changing its name in the UK or elsewhere.
Sources: en.wikipedia.org
The ABCA subfamily is composed of 12 full transporters split into two subgroups. The first subgroup consists of seven genes that map to six different chromosomes. These are ABCA1, ABCA2, ABCA3, and ABCA4, ABCA7, ABCA12, and ABCA13. The other subgroup consists of ABCA5 and ABCA6 and ABCA8, ABCA9 and ABCA10. A8-10. All of subgroup 2 is organized into a head to tail cluster of chromosomes on chromosome 17q24. Genes in this second subgroup are distinguished from ABCA1-like genes by having 37-38 exons as opposed to the 50 exons in ABCA1. The ABCA1 subgroup is implicated in the development of genetic diseases. In the recessive Tangier's disease, the ABCA1 protein is mutated. Also, the ABCA4 maps to a region of chromosome 1p21 that contains the gene for Stargardt's disease. This gene is found to be highly expressed in rod photoreceptors and is mutated in Stargardt's disease, recessive retinitis pigmentism, and the majority of recessive cone-rod dystrophy.
1 element (tin) has 10 stable isotopes 5 elements have 7 stable isotopes apiece 7 elements have 6 stable isotopes apiece 11 elements have 5 stable isotopes apiece 9 elements have 4 stable isotopes apiece 5 elements have 3 stable isotopes apiece 16 elements have 2 stable isotopes apiece 26 elements have 1 single stable isotope. These last 26 are thus called monoisotopic elements. The mean number of stable isotopes for elements which have at least one stable isotope is 251/80 = 3.1375.
=== A10BD Combinations of oral blood glucose lowering drugs === A10BD01 Phenformin and sulfonylureas A10BD02 Metformin and sulfonylureas A10BD03 Metformin and rosiglitazone A10BD04 Glimepiride and rosiglitazone A10BD05 Metformin and pioglitazone A10BD06 Glimepiride and pioglitazone A10BD07 Metformin and sitagliptin A10BD08 Metformin and vildagliptin A10BD09 Pioglitazone and alogliptin A10BD10 Metformin and saxagliptin A10BD11 Metformin and linagliptin A10BD12 Pioglitazone and sitagliptin A10BD13 Metformin and alogliptin A10BD14 Metformin and repaglinide A10BD15 Metformin and dapagliflozin A10BD16 Metformin and canagliflozin A10BD17 Metformin and acarbose A10BD18 Metformin and gemigliptin A10BD19 Linagliptin and empagliflozin A10BD20 Metformin and empagliflozin A10BD21 Saxagliptin and dapagliflozin A10BD22 Metformin and evogliptin A10BD23 Metformin and ertugliflozin A10BD24 Sitagliptin and ertugliflozin A10BD25 Metformin, saxagliptin and dapagliflozin A10BD26 Metformin and lobeglitazone A10BD27 Metformin, linagliptin and empagliflozin A10BD28 Metformin and teneligliptin A10BD29 Sitagliptin and dapagliflozin A10BD30 Gemigliptin and dapagliflozin A10BD31 Metformin, sitagliptin and dapagliflozin A10BD32 Glimepiride and dapagliflozin A10BD33 Pioglitazone and dapagliflozin A10BD34 Metformin and enavogliflozin
Sources: en.wikipedia.org
Suppliers normally quote a percentage of total chromatographic peak area, most often from reversed-phase HPLC. That figure says nothing about what the remaining percentage contains, and it depends on the detection wavelength used. A mass spectrometry result is a separate and stronger check on identity.
The methionine residue at the start of the chain is vulnerable to oxidation, producing a sulfoxide variant. Amide bonds can also hydrolyze, though more slowly under neutral conditions. Cold storage, oxygen exclusion and minimization of freeze-thaw cycles slow both processes but do not stop them.
A purity number on a certificate does not establish that a powder is the same product as a registered nasal medicine. Counter-ion content, residual solvents and peptide-related impurities may differ between the two. Independent verification is the only way to narrow that gap.
Reversed-phase high-performance liquid chromatography is the standard method, with detection in the ultraviolet range. Peak area percentage yields a purity figure for the main component. Mass spectrometry is normally run alongside to confirm molecular identity.