The short version of Photo-oxidation fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2026-07-28 and is reviewed periodically as new material appears.
Analytical characterization of tirzepatide typically employs reversed-phase high-performance liquid chromatography (RP-HPLC) for purity assessment and peptide mapping. Mass spectrometry, often coupled with electrospray ionization, confirms molecular weight and sequence integrity. Amino acid analysis and capillary electrophoresis may also be used to detect impurities or degradation products. These methods are essential for batch release and stability studies.
Storage recommendations for tirzepatide generally specify refrigeration at 2–8 °C to maintain stability. The peptide should be protected from light and kept in its original packaging to prevent aggregation or adsorption. Freezing is not recommended because freeze-thaw cycles can cause aggregation or precipitation. Once dispensed, storage conditions and in-use periods follow product-specific labeling, which may allow room temperature storage for a limited time.
Degradation pathways for tirzepatide include deamidation, oxidation, and aggregation, which are common for therapeutic peptides. These processes can be monitored by size-exclusion chromatography (SEC) for aggregates and ion-exchange chromatography for charge variants. Forced degradation studies under acidic, basic, oxidative, and thermal stress help identify potential impurities. The exact stability profile depends on formulation, concentration, and container-closure system.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white powder | Lyophilized or solid form |
| Solubility | Sparingly soluble in water | May require buffer or pH adjustment |
| Typical storage temperature | 2–8 °C | Refrigerated; protect from light |
| Common analytical method | RP-HPLC | For purity and impurity profiling |
| Molecular weight | Approximately 4813 Da | For the peptide backbone; varies with counterions |
当前公开资料把 tirzepatide 归为肠促胰素类受体双重激动剂。它并非激素天然变体，而是经过序列改造的工程化肽。其分子量、等电点与疏水性等基础参数已在药典和化学数据库中收录，可作为分析检测和质量研究的参照。
Tirzepatide 是一种由 39 个氨基酸组成的合成肽，分子结构上以 GIP 序列为骨架并引入脂肪酸侧链修饰，使其能够同时与葡萄糖依赖性促胰岛素多肽（GIP）受体和胰高血糖素样肽-1（GLP-1）受体结合。这种双重激动特性使它在同类肽类药物中区别于选择性 GLP-1 受体激动剂。该分子最早由一家制药公司在 2010 年代报道，随后进入糖尿病与体重管理领域的临床研究。
在生理层面，GIP 与 GLP-1 均为肠道内分泌细胞分泌的肠促胰素，进食后参与胰岛素分泌调节与胃排空抑制。Tirzepatide 通过同时激活这两条信号通路，使胰岛素分泌的葡萄糖依赖性增强，并延缓冲胃排空、降低食欲信号。与单一 GLP-1 激动相比，双靶点作用在血糖控制和体重变化上的效应幅度更大，但具体贡献比例仍在研究之中。
Bulk peptide material is normally characterised by reversed-phase high-performance liquid chromatography, which separates the target sequence from truncation products and other closely related impurities. Ultraviolet detection near 214 nanometres is common because the peptide backbone absorbs in that region. Mass spectrometry, usually electrospray ionisation coupled to a mass analyser, is used to confirm the molecular mass. Because the molecule carries a lipophilic side chain, gradient methods often need a relatively high organic modifier fraction to elute it within a practical retention window.
Like most synthetic peptides of this size, the material is commonly supplied as a lyophilised powder that appears white to off-white. It dissolves in aqueous buffers and in mixtures of water with a small proportion of organic solvent, though the fatty acid portion reduces solubility in pure water relative to short peptides. Hygroscopic behaviour is reported for many peptide powders, so weighing is usually performed quickly and under controlled humidity. Working solutions are typically prepared fresh and kept cold.
Long-term storage of lyophilised peptide powder is generally at minus twenty degrees Celsius or colder, with desiccant and protection from light. Short-term storage at two to eight degrees Celsius is common during active use. In solution, stability depends strongly on pH, concentration, and the presence of preservatives, and hydrolysis or aggregation can develop over weeks. Published stability data specific to this molecule are limited, so recommended conditions for research material are usually extrapolated from general peptide handling practice rather than from a dedicated study.
The molecule is a synthetic 39-amino-acid peptide whose backbone derives from the sequence of human glucose-dependent insulinotropic polypeptide, with several substitutions that raise metabolic stability and shift receptor preference. A C20 fatty diacid is attached through a short linker to a lysine side chain, a modification that increases binding to serum albumin. The reported monoisotopic mass is approximately 4813 Da. Near neutral pH the peptide carries a net negative charge, and the lipid tail makes the molecule markedly more hydrophobic than the unmodified parent sequence.
Dual agonism at the GIP and GLP-1 receptors underlies the observed pharmacology. Activation of GLP-1 receptors raises glucose-dependent insulin release, lowers glucagon secretion, slows gastric emptying and reduces appetite. GIP receptor activation contributes additional effects on adipose tissue and on energy balance, and the combined action on appetite appears larger than either pathway alone in animal models. Signalling bias and the relative contribution of each receptor arm to weight-related effects remain areas of active investigation.
In molecular biology, and more importantly high-throughput DNA sequencing, a chimera is a single DNA sequence originating when multiple transcripts or DNA sequences get joined. Chimeras can be considered artifacts and be filtered out from the data during processing to prevent spurious inferences of biological variation. However, chimeras should not be confused with chimeric reads, which are generally used by structural variant callers to detect structural variation events and are not always an indication of the presence of a chimeric transcript or gene. In a different context, the deliberate creation of artificial chimeras can also be a useful tool in molecular biology. For example, in protein engineering, "chimeragenesis" (forming chimeras between proteins that are encoded by homologous cDNAs) is one of the "two major techniques used to manipulate cDNA sequences". For gene fusions that occur through natural processes, see chimeric genes and fusion genes.
Individual transmembrane adenylyl cyclase isoforms have been linked to numerous physiological functions. Soluble adenylyl cyclase (sAC, AC10) has a critical role in sperm motility. Adenylyl cyclase has been implicated in memory formation, functioning as a coincidence detector. AC-IV was first reported in the bacterium Aeromonas hydrophila, and the structure of the AC-IV from Yersinia pestis has been reported. These are the smallest of the AC enzyme classes; the AC-IV (CyaB) from Yersinia is a dimer of 19 kDa subunits with no known regulatory components (PDB: 2FJT). AC-IV forms a superfamily with mammalian thiamine-triphosphatase called CYTH (CyaB, thiamine triphosphatase). These forms of AC have been reported in specific bacteria (Prevotella ruminicola O68902 and Rhizobium etli Q8KY20, respectively) and have not been extensively characterized. There are a few extra members (~400 in Pfam) known to be in class VI. Class VI enzymes possess a catalytic core similar to the one in Class III.
Absorption is the journey of a drug travelling from the site of administration to the site of action. The drug travels by some route of administration (oral, topical-dermal, etc.) in a chosen dosage form (e.g., tablets, capsules, or in solution). Absorption by some other routes, such as intravenous therapy, intramuscular injection, enteral nutrition, is even more straightforward and there is less variability in absorption and bioavailability is often near 100%. Intravascular administration does not involve absorption, and there is no loss of drug. The fastest route of absorption is inhalation. Absorption is a primary focus in drug development and medicinal chemistry, since a drug must be absorbed before any medicinal effects can occur. Moreover, the drug's pharmacokinetic profile can be easily and significantly changed by adjusting factors that affect absorption.
A clinical data management system (CDMS) is a tool used in clinical research to manage the data of a clinical trial. The clinical trial data gathered at the investigator site in the case report form are stored in the CDMS. To reduce the possibility of errors due to human entry, the systems employ various means to verify the data. Systems for clinical data management can be self-contained or part of the functionality of a CTMS. A CTMS with clinical data management functionality can help with the validation of clinical data as well as helps the site employ for other important activities like building patient registries and assist in patient recruitment efforts. The CDMS can be broadly divided into paper-based and electronic data capture systems.
Sources: en.wikipedia.org
Wheeler was awarded the Lab on a Chip Pioneers in Miniaturization Award (2017), an E.W.R. Steacie Fellowship from the Natural Sciences and Engineering Research Council of Canada (NSERC) (2015), a Connaught Foundation McLean Fellowship (2014), the Joseph Black Award from the Royal Society of Chemistry (2012), the Arthur F. Findeis Award from the American Chemical Society (2012), the Young Innovator Award in Analytical Chemistry (2011), and a Sloan Research Fellowship (2009). In January 2024, Wheeler was honored with the Ricardo Aroca Award, recognizing his contributions to analytical chemistry and advancing lab-on-a-chip techniques, particularly through the use of digital microfluidics (DMF), which enables precise manipulation of liquid droplets on electrode arrays. The Award is bestowed upon a scientist living in Canada who has made a notable contribution to the discipline of analytical chemistry while conducting research within the country.
Amino acids are the building blocks of protein and together they form the protein requirements in formula needed for growth and development. The amino acids are in the simplest form, making it easy for the body to process and digest. Amino acid-based formula may be considered hypoallergenic since it does not contain peptides that may trigger an immune response. Because infants and children have different nutritional needs, amino acid-based formulas are typically formulated either for infants 0–1 years of age or for children 1–10 years of age. Amino acid-based formulas may be used for those with cow's milk or soy protein allergy. However, most infants who suffer from food allergy respond well to extensively hydrolysed formulas, and only few of those with the most severe form of the illness require the use of amino acid-based formulas. It may also be used for other medical conditions requiring an amino acid-based diet, such as short bowel syndrome, and for transition from parenteral to enteral nutrition. Milk allergy Food allergy
APCs naturally have a role in fighting tumors, via stimulation of B and cytotoxic T cells to respectively produce antibodies against tumor-related antigen and kill malignant cells. Dendritic cells, presenting tumor-specific antigen to T cells, are key to this process. Cancer therapies have included treating the patient with increased numbers of dendritic cells or cancer-specific T cells. However, newer therapies have turned to genetically engineered artificial antigen-presenting cells designed to prime the immune system to attack malignant cells. Some artificial APCs are derived from human cells; others are acellular, containing MHC proteins, co-stimulatory molecules and the necessary peptides. The APC activator IMP321 is being tested in clinical trials to accelerate the immune reaction to eliminate metastatic breast cancer or melanoma. Antigen: protease degradation on YouTube – PMAP animation Antigen-Presenting+Cells at the U.S. National Library of Medicine Medical Subject Headings (MeSH)
Sources: en.wikipedia.org
Synthesis of pre-vitamin D3 in the skin involves UVB radiation, which effectively penetrates only the epidermal layers of skin. 7-Dehydrocholesterol absorbs UV light most effectively at wavelengths between 295 and 300 nm and, thus, the production of vitamin D3 will occur primarily at those wavelengths. The two most important factors that govern the generation of pre-vitamin D3 are the quantity (intensity) and quality (appropriate wavelength) of the UVB irradiation reaching the 7-dehydrocholesterol deep in the stratum basale and stratum spinosum. Light-emitting diodes (LEDs) can be used to produce the radiation. Another important consideration is the quantity of 7-dehydrocholesterol present in the skin. Under normal circumstances, ample quantities of 7-dehydrocholesterol (about 25–50 μg/cm2 of skin) are available in the stratum spinosum and stratum basale of human skin to meet the body's vitamin D requirements. 7-DHC insufficiency has been proposed as an alternate cause for Vitamin D deficiency.
AAV is of particular interest to gene therapists due to its apparent limited capacity to induce immune responses in humans, a factor which should positively influence vector transduction efficiency while reducing the risk of any immune-associated pathology. AAV is not considered to have any known role in disease. However, host immune system response and immune tolerance reduce the efficacy of AAV-mediated gene therapy. Host immune response has been shown to respond to the AAV vectors, the transduced cells, and the transduced proteins. The immune response can be subdivided into two categories: innate and adaptive, the latter of which is divided into humoral and cell-mediated.
Network Science, Part 5: Solvent-Accessible Surfaces AREAIMOL is a command line tool in the CCP4 Program Suite for calculating ASA. NACCESS solvent accessible area calculations. FreeSASA Open source command line tool, C library and Python module for calculating ASA. Surface Racer Oleg Tsodikov's Surface Racer program. Solvent accessible and molecular surface area and average curvature calculation. Free for academic use. ASA.py — a Python-based implementation of the Shrake-Rupley algorithm. Michel Sanner's Molecular Surface – the fastest program to calculate the excluded surface. pov4grasp render molecular surfaces. Molecular Surface Package — Michael Connolly's program. Volume Voxelator — A web-based tool to generate excluded surfaces. ASV freeware Analytical calculation of the volume and surface of the union of n spheres (Monte-Carlo calculation also provided). Vorlume Computing Surface Area and Volume of a Family of 3D Balls. GetArea Calculate solvent accessible surface area of proteins online. ProMS ProMS - Protein Molecular Surface Calculator
Sources: en.wikipedia.org
RP-HPLC is widely used for purity and impurity profiling. Mass spectrometry confirms identity.
Typically refrigerated at 2–8 °C. Protect from light and avoid freezing.
Deamidation, oxidation, and aggregation products. SEC and ion-exchange chromatography are used.
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.