A practical reference on deamidation: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-05-25. Anything still debated is marked as such rather than presented as settled.
Development began in the 2010s, when researchers modified a GIP-based scaffold to add GLP-1 activity and then attached the fatty diacid to lengthen its half-life. Clinical evaluation proceeded through large phase 3 programmes in type 2 diabetes and in obesity, and regulators in the United States cleared the compound for type 2 diabetes in 2022 and for chronic weight management in 2023. Several cardiovascular and metabolic outcome studies are still reporting, so the picture of long-term benefit and risk is incomplete. Approvals in other regions followed on different timelines.
Tirzepatide is a synthetic peptide of 39 amino acids that carries a C20 fatty diacid side chain attached through a linker. Its molecular formula is C225H348N48O68, and its molecular weight is about 4813 daltons. The compound belongs to the incretin mimetic class and is administered by subcutaneous injection. The fatty acid chain promotes binding to serum albumin, which slows renal clearance and extends the circulation time of the molecule. It was identified during screening of sequences derived from glucose-dependent insulinotropic polypeptide.
Lyophilized material is generally held at -20 degrees Celsius or lower, desiccated and protected from light, where it remains stable for extended periods. Reconstituted or ready-to-use solution is usually kept at 2 to 8 degrees Celsius with minimal agitation. Repeated freeze-thaw cycles should be avoided because they promote aggregation and reduce the soluble monomer fraction. Shipment of frozen solid commonly uses dry ice, while refrigerated liquid moves with validated cold packs. Stability beyond documented periods is not established.
Characterization of the peptide relies on reversed-phase high-performance liquid chromatography for purity and related-substance profiling, with ultraviolet detection near 214 nanometers. Mass spectrometry confirms molecular mass and reveals modifications such as oxidation or deamidation. Peptide mapping after enzymatic digestion verifies the amino acid sequence, while amino acid analysis supplies compositional data. Circular dichroism and infrared spectroscopy are used to assess secondary structure, particularly the alpha-helical content that influences aggregation behavior in solution.
Common degradation routes include hydrolysis of labile amide bonds, deamidation of asparagine and glutamine residues, oxidation of methionine and tryptophan, and non-covalent aggregation. Aggregates can form during freeze-thaw cycling, at elevated pH, or when peptide concentration is high. Each route produces characteristic chromatographic or mass shifts that are tracked during stability studies. Whether a given minor impurity alters biological activity is often an open question, and specification limits are typically set on identity and purity rather than on functional data for trace species.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C225H348N48O68 | Peptide backbone with a fatty diacid chain |
| Molecular weight | About 4813 Da | Calculated from the formula |
| Receptor targets | GIP and GLP-1 receptors | Dual agonist activity at both sites |
| Route of administration | Subcutaneous injection | No approved oral form at present |
| Elimination half-life | About 5 days | Supports extended intervals between administrations |
Stability depends strongly on physical form. The dry powder is generally regarded as stable for extended periods when held at or below minus twenty degrees Celsius in a sealed, desiccated container. In solution, degradation pathways include deamidation of asparagine and glutamine residues, oxidation of methionine, and aggregation. Reaction rates for these pathways rise with temperature. Repeated freezing and thawing of solutions promotes aggregation, and light exposure can accelerate some oxidative changes. Buffer composition and pH influence which pathway dominates at a given temperature.
Regulatory and quality discussions place the peptide within established guidance for synthetic peptides and biologics. Forced degradation studies, in which samples are exposed to heat, acid, base, peroxide, and light, identify likely degradation products and validate the selectivity of analytical methods. Reference standards allow comparison across laboratories and production batches. Purity specifications reported in the literature usually combine chromatographic purity with mass confirmation. Which impurity thresholds are meaningful for long-term behavior is still debated, and no single universal specification has been adopted across all jurisdictions.
Routine characterization of the peptide relies on reversed-phase high-performance liquid chromatography for purity assessment, usually with ultraviolet detection near 214 nanometers. Intact mass measurement by liquid chromatography coupled to mass spectrometry confirms molecular identity against a theoretical value. Sequence-level confirmation uses enzymatic digestion followed by tandem mass spectrometry, an approach known as peptide mapping. Amino acid analysis gives an independent check on composition. Circular dichroism spectra are used to estimate helical content in aqueous buffer.
Identity and purity are assessed by reversed-phase high-performance liquid chromatography, with mass confirmation by electrospray ionisation mass spectrometry. Peptide mapping after enzymatic digestion verifies the primary sequence. Size-exclusion chromatography quantifies aggregates, while circular dichroism provides a secondary-structure fingerprint. Bioanalytical quantification in plasma uses immunoassay or LC-MS/MS. Reported purity for research-grade lots is commonly 95 percent or higher, and residual water content is checked by Karl Fischer titration.
As a peptide, tirzepatide is handled as a lyophilised solid in research settings and as a preserved solution in finished products. Aqueous solubility is pH dependent and reaches a minimum near the isoelectric point, which lies close to pH 5.4. Stock solutions are typically prepared in neutral or slightly basic buffer to limit precipitation. The solid is hygroscopic and should be equilibrated to room temperature before opening so that condensation does not form on the powder surface.
Research-grade material circulates through suppliers that differ widely in documentation and testing practice, so a certificate of analysis is a starting point rather than proof of quality. Independent verification typically repeats chromatographic purity and mass confirmation on the received lot, and compares results against a retained reference standard. Regulatory status varies by jurisdiction, and a substance cleared as a medicine is not interchangeable with a research chemical of the same name. Open questions include how closely non-pharmaceutical lots match approved material in impurity profile and in aggregate content.
Solid tirzepatide is handled as a lyophilised, hygroscopic peptide powder that should be kept desiccated, protected from light, and stored frozen, typically at or below minus twenty degrees Celsius for long-term retention. Material left at ambient temperature for extended periods can take up moisture, which promotes aggregation and deamidation. Commercial liquid presentations are kept refrigerated between two and eight degrees Celsius and are not frozen. Reconstituted laboratory solutions are generally held cold and used within a short window because hydrolysis and oxidation continue slowly in solution.
=== Steroid Chemistry === As a PhD student in the laboratories of future Nobel Laureates, Leopold Ruzicka and Tadeus Reichstein in Zürich, Hofmann synthesized a number of compounds related to terpenes, the hypothetical building block of steroids. One of these was a dehydroandrosterone derivative, a prototype for the birth control pill. Unfortunately the biological basis for reproduction was not known for many years subsequent to this and therefore the importance of this compound was not recognized.
== Veterinary use == Naloxone is used to reverse pure μ-opioid receptor agonists and for opioid reversal during cardiopulmonary arrest in cats and dogs. This is often given intravenously but instranasal administration works in the dog at higher doses. Renarcotisation can occur with naloxone administration, especially with morphinans. Naloxone administration has been reported to result in altered mental status and blepharospasm. Aetiology of this is unknown but could be due to either withdrawal, systemic hypertension, or rapid changes to the cerebral vascular tone. One study in horses reported that naloxone administration reduced increases in right ventricular pressure and heart rate caused by endotoxic shock.
16 July – Starmer suspends Neil Duncan-Jordan, Brian Leishman, Chris Hinchliff and Rachael Maskell from the Parliamentary Labour Party for repeated breaches of party discipline. 17 July – Prime Minister Keir Starmer and German Chancellor Friedrich Merz sign the Kensington Treaty during Merz's first official visit to the UK. The treaty includes plans for a direct train link between London and Berlin. Publication of the Elections Bill, which includes provisions for lowering the age of voting to 16 for the next general election. Diane Abbott is suspended from the Labour Party pending an investigation into comments she is alleged to have made about racism. 18 July – Sir Wayne David announces he is standing down as chief special adviser to Eluned Morgan for health reasons. 20 July – Nigel Farage accuses council officials of obstructing the work of Reform UK councillors as he defends the way the party is running some local authorities. 21 July – Nigel Farage proposes creating 30,000 prison places by sending some UK prisoners overseas to serve their sentences, repatriating foreign prisoners accommodated in UK prisons and building five new prisons. He also proposes recruiting a further 30,000 police officers. Outgoing Scottish Greens co-leader Patrick Harvie is selected as the party's top candidate for the Scottish Parliament's Glasgow regional constituency, giving him a strong change of re-election at the 2026 Scottish Parliament election. 22 July – Kemi Badenoch conducts a shadow cabinet reshuffle, her first as Leader of the Opposition.
==== 2000-2009 ==== In 2000, Teva acquired Canada-based Novopharm. In October 2003, Teva announced its intentions to acquire Sicor Inc. for $3.4 billion. Following the announcement, the acquisition was completed on January 22, 2004, which marked Teva's entry into biosimilars' market. In 2005, Teva opened a new, state-of-the-art pharmaceutical manufacturing plant in Har Hotzvim, a technology park in Jerusalem. The plant received FDA approval in early 2007. Teva entered the Japanese market in 2005 and in 2008 established a generics joint venture with Kowa. In January 2006, Teva acquired its U.S. rival Ivax Corporation for $7.4 billion. In 2008, sales totalled $11.08 billion, $13.9 billion in 2009, and in 2010 total sales rose to $16.1 billion, of which a major portion was in Europe and North America. In July 2008, Teva announced it completed the acquisition of Bentley Pharmaceuticals for its generic pharmaceutical operations in Spain for $360 million in cash. On December 23, 2008, Teva acquired Barr Pharmaceuticals for $7.5 billion, making Barr and Pliva (which Barr bought earlier) part of Teva.
=== Contraindications === Although cruciferous vegetables are generally safe for human consumption, individuals with known allergies or hypersensitivities to a certain Brassica vegetable, or those taking anticoagulant therapy, should be cautious.
Sources: en.wikipedia.org
Epicutaneous (application onto the skin). It can be used both for local effect as in allergy testing and typical local anesthesia, as well as systemic effects when the active substance diffuses through skin in a transdermal route. Sublingual and buccal medication administration is a way of giving someone medicine orally (by mouth). Sublingual administration is when medication is placed under the tongue to be absorbed by the body. The word "sublingual" means "under the tongue." Buccal administration involves placement of the drug between the gums and the cheek. These medications can come in the form of tablets, films, or sprays. Many drugs are designed for sublingual administration, including cardiovascular drugs, steroids, barbiturates, opioid analgesics with poor gastrointestinal bioavailability, enzymes and, increasingly, vitamins and minerals. Extra-amniotic administration, between the endometrium and fetal membranes. Nasal administration (through the nose) can be used for topically acting substances, as well as for insufflation of e.g. decongestant nasal sprays to be taken up along the respiratory tract. Such substances are also called inhalational, e.g. inhalational anesthetics. Intra-arterial (into an artery), e.g. vasodilator drugs in the treatment of vasospasm and thrombolytic drugs for treatment of embolism. Intra-articular, into a joint space. It is generally performed by joint injection. It is mainly used for symptomatic relief in osteoarthritis. Intracardiac (into the heart), e.g. adrenaline during cardiopulmonary resuscitation (no longer commonly performed).
== Mechanism of self-resistance == Lariocidin-producing Paenibacillus sp. M2 encodes a GCN5-related N-acetyltransferase LrcE. Its gene is a part of the lariocidin biosynthetic gene cluster. LrcE specifically acetylates the side chain of LAR's Lys16, which reduces compound's affinity to the binding site on the ribosome. Similarly acting acetyltransferases confer resistance to LAR-like lasso peptides triculamin (TriT) and gelatinamin (GelT).
Griffin, J. P. (2004). "Venetian treacle and the foundation of medicines regulation". British Journal of Clinical Pharmacology. 58 (3): 317–325. doi:10.1111/j.1365-2125.2004.02147.x. PMC 1884566. PMID 15327592. Raj D, Pękacka-Falkowska K, Włodarczyk M, Węglorz J. The real Theriac - panacea, poisonous drug or quackery? J Ethnopharmacol. 2021 Dec 5;281:114535. doi: 10.1016/j.jep.2021.114535. Epub 2021 Aug 17. PMID: 34416297.
== Adverse effects == The most common side effects of pivekimab sunirine include swelling (edema), tiredness (fatigue), muscle and joint pain (musculoskeletal pain), bleeding (hemorrhage), infusion-related reactions, nausea, diarrhea, changes in kidney function tests (increased creatinine), low albumin levels, and changes in liver function tests (transaminases increased). The US prescribing information includes a boxed warning for hepatotoxicity, including hepatic veno-occlusive disease, and warnings and precautions for infusion-related reactions, edema, sulfite allergic reactions, and embryo-fetal toxicity. Pivekimab sunirine may cause a severe form of liver damage (hepatotoxicity) called veno-occlusive disease (blockage of small blood vessels that makes it hard for blood to leave the liver, leading to backup and swelling), including severe or fatal hepatic veno-occlusive disease (also known as sinusoidal obstruction syndrome). Pivekimab sunirine may cause a serious side effect called infusion-related reaction, which may be life-threatening or lead to death if not treated. Pivekimab sunirine contains sulfite and may cause severe, life-threatening allergic reactions in some people. Pivekimab sunirine may cause severe fluid retention and harm to an unborn baby.
Sources: en.wikipedia.org
It also saw the first "Era of Progress" as the college transformed from a college supported by the religious community (which focused primarily upon training young men and women for the ministry) to a college gaining support from private foundations, and offering liberal arts academic degree for a variety of professions. In 1915, Andrew Carnegie donated to the school a grant of $50,000 for a central academic building. The terms of the grant included the purchase of a new site for the College, payment of all outstanding obligations, and the construction of a building to be named after him. The College met the conditions and moved to its present site in northeast Baltimore in 1917. In 1918, the white community of Lauraville tried to have the sale revoked by filing suit in the circuit court in Towson, upset that the Ivy Mill property, the planned location of Morgan State, had been sold to a "negro" college. The circuit court dismissed the suit, which the community appealed to the Maryland Court of Appeals. The appellate court upheld the lower court decision, finding no basis that siting the college at this location would constitute a public nuisance. Despite some ugly threats and several demonstrations against the project, Morgan College was constructed at the new site and later expanded. Carnegie Hall, the oldest original building on the present Morgan campus, was erected a year later. Morgan remained a private institution until 1939. That year, the state of Maryland purchased the school. Morgan College became Morgan State College.
== Property evaluation == One should evaluate the properties (mechanical, electronic, optical, magnetic, etc.) of the material that has been chosen and indicate what the major differences would be if the same material were not at nanoscale. Nanotubes formed from dipeptides are stable under extreme conditions. Dry nanotubes do not degrade until 200 °C; nanotubes display exceptional chemical stability at a range of pH and in the presence of organic solvents. This is a marked difference from natural biological systems, which are often unstable and sensitive to temperature and chemical conditions. Indentation-atomic-force-microscopy experiments showed that dry nanotubes on mica have an average stiffness of 160 N/m and a high Young's modulus of 19–27 GPa. Although they are less stiff than carbon and non-carbon nanotubes, with these values these nanotubes are amongst some of the stiffest known biological materials. The mechanisms which facilitates the mechanical stiffness has been suggested to be the intermolecular hydrogen bonds and rigid aromatic side chains on the peptides. Apart from those made by cyclic peptides, the nanotubes' inner and outer surface properties have not yet been successfully independently modified. Hence, it presents a limitation that the inner and outer tube surfaces are identical. Molecular assembly mostly occurs through weak non-covalent bonds, which include: hydrogen bonds, ionic bonds, van der Waals interactions, and hydrophobic interactions.
==== Phenibut ==== Phenibut (Anvifen, Fenibut, Noofen) is an anxiolytic used in Russia. Phenibut is a GABAB receptor agonist, as well as an antagonist at α2δ subunit-containing voltage-dependent calcium channels (VDCCs), similarly to gabapentinoids like gabapentin and pregabalin. The medication is not approved by the FDA for use in the United States, but is sold online as a supplement.
=== Black box warning === In January 2012, the FDA announced that because brentuximab vedotin had been linked with two cases of progressive multifocal leukoencephalopathy, they were requiring the addition of a black box warning to the drug label regarding this potential risk.
== Miscellaneous nomenclature == Any non-racemic chiral substance is called scalemic. Scalemic materials can be enantiopure or enantioenriched. A chiral substance is enantiopure when only one of two possible enantiomers is present so that all molecules within a sample have the same chirality sense. Use of homochiral as a synonym is strongly discouraged. A chiral substance is enantioenriched or heterochiral when its enantiomeric ratio is greater than 50:50 but less than 100:0. Enantiomeric excess or e.e. is the difference between how much of one enantiomer is present compared to the other. For example, a sample with 40% e.e. of R contains 70% R and 30% S (70% − 30% = 40%).
Sources: en.wikipedia.org
It is a synthetic 39-amino-acid peptide that acts on two incretin receptors, the GIP receptor and the GLP-1 receptor. It is given by subcutaneous injection and has a circulating half-life of roughly five days. It is not a small molecule and is not absorbed usefully from the gut in conventional oral form.
Selective agents act on one receptor, while tirzepatide engages both GIP and GLP-1 receptors. The added GIP activity may contribute effects on insulin sensitivity and on fat metabolism. Whether the dual action produces meaningful clinical advantages beyond differences in potency is still being examined.
The downstream consequences of GIP receptor activation are not fully characterised in humans. It is also unclear how much each receptor contributes to appetite reduction and to shifts in body composition. Published work describes associations and proposed pathways rather than settled causal chains.
Reversed-phase high-performance liquid chromatography is the standard approach, separating the main peak from related impurities. Ultraviolet detection near 214 nanometers captures the peptide backbone. Mass spectrometry is then used alongside chromatography to confirm identity and detect covalent modifications.