13C,15N Tirzepatide is the 13C,15N-labelled form of Tirzepatide (LY-3298176; Mounjaro)(Tirzepatide internal standard), which is a first-in-class dual glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptor agonist that has been approved by FDA in May 2022 for the treatment of type 2 diabetes.

Physicochemical Properties

Molecular Formula	C219[13C]6H347N47[15N]1NAO68
Molecular Weight	4842.38 (Sodium salt)
Exact Mass	4817.5420
Related CAS #	2023788-19-2;13C,15N Tirzepatide;Tirzepatide hydrochloride (LY3298176 hydrochloride)
Appearance	Solid powder
Synonyms	Tirzepatide internal standard; Labeled tirzepatide;isotope labeled tirzepatide;fluorescently labeled tirzepatide
HS Tariff Code	2934.99.9001
Storage	Powder-20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month
Shipping Condition	Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Biological Activity

Targets	Glucose-dependent insulin nutritive polypeptide (GIP) Glucagon-like peptide-1 (GLP-1) receptor
ln Vitro	Core Concept ¹³C and ¹⁵N are naturally occurring stable isotopes that are non-radioactive. Incorporating them into target molecules (e.g., drugs, metabolites) provides a unique "ID tag" or "tracer." This tag behaves almost identically to the original molecule in terms of chemical properties, but its slight mass difference can be precisely identified and distinguished by sensitive instruments like mass spectrometers. This enables researchers to accurately track the fate, transformation, and quantity of target molecules within complex biological systems. Primary Applications 1. Pharmacokinetic Studies This is one of the core applications. By administering the isotopically labeled drug to animals or humans, researchers can systematically and accurately study the entire "life cycle" of the drug in the body—its absorption, distribution, metabolism, and excretion (ADME). This helps determine the drug's targeting, concentration profiles in blood and tissues, half-life, and clearance pathways, providing critical data for new drug development and clinical dosing regimen design. 2. Metabolomics and Metabolic Pathway Research In metabolic studies, the labeled compounds serve as tracers. By tracking the flow and transformation of ¹³C or ¹⁵N atoms within the body's complex metabolic networks (such as glucose, lipid, and amino acid metabolism), the metabolic fate of specific molecules and how drug interventions affect these pathways can be clearly mapped. This is crucial for understanding a drug's mechanism of action and potential side effects. 3. Quantitative Analysis in Biological Samples (as Internal Standards) A major challenge in quantifying drugs or their metabolites in complex biological samples (e.g., plasma, urine, tissue) using mass spectrometry is sample matrix interference and analytical variability. Adding a known amount of a ¹³C/¹⁵N-labeled analog (as an internal standard) to the sample solves this. Because the labeled standard co-elutes and ionizes almost identically to the analyte but is distinguishable by mass, it undergoes the exact same processing steps. By comparing their signal intensities, the absolute concentration of the analyte can be calculated with high precision, making this the gold-standard quantitative method. 4. Proteomics Research In protein quantitative analysis, ¹³C/¹⁵N-labeled peptides are a fundamental technical tool. For example, in the "Absolute Quantification" technique, synthesized labeled peptides serve as internal standards with precisely known concentrations. More broadly, in techniques like Stable Isotope Labeling by Amino acids in Cell culture (SILAC), comparing the mass spectrometry signal ratios of labeled versus unlabeled proteins/peptides allows for large-scale, high-throughput study of changes in protein expression under different physiological or pathological states. This is used to discover disease biomarkers or study drug targets. Technical Summary In summary, ¹³C and ¹⁵N stable isotope labeling is a powerful platform technology. Its core value lies in tracing and precise quantification. For a peptide drug like Tirzepatide, synthesizing a ¹³C,¹⁵N-labeled version is primarily intended to enable the clearest and most reliable elucidation of the drug molecule's behavior in cutting-edge metabolic, pharmacokinetic, and quantitative analytical research.
References	[1]. Efficacy and safety of LY3298176, a novel dual GIP and GLP-1 receptor agonist, in patients with type 2 diabetes: a randomised, placebo-controlled and active comparator-controlled phase 2 trial. Lancet. 2018 Nov 17;392(10160):2180-2193. [2]. Tirzepatide is an imbalanced and biased dual GIP and GLP-1 receptor agonist. JCI Insight. 2020 Sep 3; 5(17): e140532. [3]. LY3298176, a novel dual GIP and GLP-1 receptor agonist for the treatment of type 2 diabetes mellitus: From discovery to clinical proof of concept. Mol Metab. 2018 Dec:18:3-14. [4]. Tirzepatide ameliorates spatial learning and memory impairment through modulation of aberrant insulin resistance and inflammation response in diabetic rats. Front Pharmacol. 2023 Aug 28;14:1146960.
Additional Infomation	Pharmacodynamics Tirzepatide is a synthetic peptide with glucose-lowering effects. It works to stimulate first- and second-phase insulin secretion, and reduces glucagon levels, both in a glucose-dependent manner. Tirzepatide was also shown to delay gastric emptying, lower fasting and postprandial glucose concentration, decrease food intake, and reduce body weight in patients with type 2 diabetes. Tirzepatide can increase insulin sensitivity. As the peptide is conjugated to a C20 fatty diacid moiety through a hydrophilic linker at the lysine residue at position 20, the drug is highly bound to albumin in the plasma, which prolongs its half-life.\n \nBackground: LY3298176 is a novel dual glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptor agonist that is being developed for the treatment of type 2 diabetes. We aimed to examine the efficacy and safety of co-stimulation of the GLP-1 and GIP receptors with LY3298176 compared with placebo or selective stimulation of GLP-1 receptors with dulaglutide in patients with poorly controlled type 2 diabetes.\n\nMethods: In this double-blind, randomised, phase 2 study, patients with type 2 diabetes were randomly assigned (1:1:1:1:1:1) to receive either once-weekly subcutaneous LY3298176 (1 mg, 5 mg, 10 mg, or 15 mg), dulaglutide (1·5 mg), or placebo for 26 weeks. Assignment was stratified by baseline glycated haemoglobin A1c (HbA1c), metformin use, and body-mass index (BMI). Eligible participants (aged 18-75) had type 2 diabetes for at least 6 months (HbA1c 7·0-10·5%, inclusive), that was inadequately controlled with diet and exercise alone or with stable metformin therapy, and a BMI of 23-50 kg/m2. The primary efficacy outcome was change in HbA1c from baseline to 26 weeks in the modified intention-to-treat (mITT) population (all patients who received at least one dose of study drug and had at least one postbaseline measurement of any outcome). Secondary endpoints, measured in the mITT on treatment dataset, were change in HbA1c from baseline to 12 weeks; change in mean bodyweight, fasting plasma glucose, waist circumference, total cholesterol, LDL cholesterol, HDL cholesterol, and triglycerides, and proportion of patients reaching the HbA1c target (≤6·5% and <7·0%) from baseline to weeks 12 and 26; and proportion of patients with at least 5% and 10% bodyweight loss from baseline to 26 weeks. This study is registered with ClinicalTrials.gov, number NCT03131687.\n\nFindings: Between May 24, 2017, and March 28, 2018, 555 participants were assessed for eligibility, of whom 318 were randomly assigned to one of the six treatment groups. Because two participants did not receive treatment, the modified intention-to-treat and safety populations included 316 participants. 258 (81·7%) participants completed 26 weeks of treatment, and 283 (89·6%) completed the study. At baseline, mean age was 57 years (SD 9), BMI was 32·6 kg/m2 (5·9), duration from diagnosis of diabetes was 9 years (6), HbA1c was 8·1% (1·0), 53% of patients were men, and 47% were women. At 26 weeks, the effect of LY3298176 on change in HbA1c was dose-dependent and did not plateau. Mean changes from baseline in HbA1c with LY3298176 were -1·06% for 1 mg, -1·73% for 5 mg, -1·89% for 10 mg, and -1·94% for 15 mg, compared with -0·06% for placebo (posterior mean differences [80% credible set] vs placebo: -1·00% [-1·22 to -0·79] for 1 mg, -1·67% [-1·88 to -1·46] for 5 mg, -1·83% [-2·04 to -1·61] for 10 mg, and -1·89% [-2·11 to -1·67] for 15 mg). Compared with dulaglutide (-1·21%) the posterior mean differences (80% credible set) for change in HbA1c from baseline to 26 weeks with the LY3298176 doses were 0·15% (-0·08 to 0·38) for 1 mg, -0·52% (-0·72 to -0·31) for 5 mg, -0·67% (-0·89 to -0·46) for 10 mg, and -0·73% (-0·95 to -0·52) for 15 mg. At 26 weeks, 33-90% of patients treated with LY3298176 achieved the HbA1c target of less than 7·0% (vs 52% with dulaglutide, 12% with placebo) and 15-82% achieved the HbA1c target of at least 6·5% (vs 39% with dulaglutide, 2% with placebo). Changes in fasting plasma glucose ranged from -0·4 mmol/L to -3·4 mmol/L for LY3298176 (vs 0·9 mmol/L for placebo, -1·2 mmol/L for dulaglutide). Changes in mean bodyweight ranged from -0·9 kg to -11·3 kg for LY3298176 (vs -0·4 kg for placebo, -2·7 kg for dulaglutide). At 26 weeks, 14-71% of those treated with LY3298176 achieved the weight loss target of at least 5% (vs 22% with dulaglutide, 0% with placebo) and 6-39% achieved the weight loss target of at least 10% (vs 9% with dulaglutide, 0% with placebo). Changes in waist circumference ranged from -2·1 cm to -10·2 cm for LY3298176 (vs -1·3 cm for placebo, -2·5 cm for dulaglutide). Changes in total cholesterol ranged from 0·2 mmol/L to -0·3 mmol/L for LY3298176 (vs 0·3 mmol/L for placebo, -0·2 mmol/L for dulaglutide). Changes in HDL or LDL cholesterol did not differ between the LY3298176 and placebo groups. Changes in triglyceride concentration ranged from 0 mmol/L to -0·8 mmol/L for LY3298176 (vs 0·3 mmol/L for placebo, -0·3 mmol/L for dulaglutide). The 12-week outcomes were similar to those at 26 weeks for all secondary outcomes. 13 (4%) of 316 participants across the six treatment groups had 23 serious adverse events in total. Gastrointestinal events (nausea, diarrhoea, and vomiting) were the most common treatment-emergent adverse events. The incidence of gastrointestinal events was dose-related (23·1% for 1 mg LY3298176, 32·7% for 5 mg LY3298176, 51·0% for 10 mg LY3298176, and 66·0% for 15 mg LY3298176, 42·6% for dulaglutide, 9·8% for placebo); most events were mild to moderate in intensity and transient. Decreased appetite was the second most common adverse event (3·8% for 1 mg LY3298176, 20·0% for 5 mg LY3298176, 25·5% for 10 mg LY3298176, 18·9% for 15 mg LY3298176, 5·6% for dulaglutide, 2·0% for placebo). There were no reports of severe hypoglycaemia. One patient in the placebo group died from lung adenocarcinoma stage IV, which was unrelated to study treatment.\n\nInterpretation: The dual GIP and GLP-1 receptor agonist, LY3298176, showed significantly better efficacy with regard to glucose control and weight loss than did dulaglutide, with an acceptable safety and tolerability profile. Combined GIP and GLP-1 receptor stimulation might offer a new therapeutic option in the treatment of type 2 diabetes. [1] \n\nTirzepatide (LY3298176) is a dual GIP and GLP-1 receptor agonist under development for the treatment of type 2 diabetes mellitus (T2DM), obesity, and nonalcoholic steatohepatitis. Early phase trials in T2DM indicate that tirzepatide improves clinical outcomes beyond those achieved by a selective GLP-1 receptor agonist. Therefore, we hypothesized that the integrated potency and signaling properties of tirzepatide provide a unique pharmacological profile tailored for improving broad metabolic control. Here, we establish methodology for calculating occupancy of each receptor for clinically efficacious doses of the drug. This analysis reveals a greater degree of engagement of tirzepatide for the GIP receptor than the GLP-1 receptor, corroborating an imbalanced mechanism of action. Pharmacologically, signaling studies demonstrate that tirzepatide mimics the actions of native GIP at the GIP receptor but shows bias at the GLP-1 receptor to favor cAMP generation over β-arrestin recruitment, coincident with a weaker ability to drive GLP-1 receptor internalization compared with GLP-1. Experiments in primary islets reveal β-arrestin1 limits the insulin response to GLP-1, but not GIP or tirzepatide, suggesting that the biased agonism of tirzepatide enhances insulin secretion. Imbalance toward GIP receptor, combined with distinct signaling properties at the GLP-1 receptor, together may account for the promising efficacy of this investigational agent. [2] \n\nObjective: A novel dual GIP and GLP-1 receptor agonist, LY3298176, was developed to determine whether the metabolic action of GIP adds to the established clinical benefits of selective GLP-1 receptor agonists in type 2 diabetes mellitus (T2DM).\n\nMethods: LY3298176 is a fatty acid modified peptide with dual GIP and GLP-1 receptor agonist activity designed for once-weekly subcutaneous administration. LY3298176 was characterised in vitro, using signaling and functional assays in cell lines expressing recombinant or endogenous incretin receptors, and in vivo using body weight, food intake, insulin secretion and glycemic profiles in mice. A Phase 1, randomised, placebo-controlled, double-blind study was comprised of three parts: a single-ascending dose (SAD; doses 0.25-8 mg) and 4-week multiple-ascending dose (MAD; doses 0.5-10 mg) studies in healthy subjects (HS), followed by a 4-week multiple-dose Phase 1 b proof-of-concept (POC; doses 0.5-15 mg) in patients with T2DM (ClinicalTrials.gov no. NCT02759107). Doses higher than 5 mg were attained by titration, dulaglutide (DU) was used as a positive control. The primary objective was to investigate safety and tolerability of LY3298176.\n\nResults: LY3298176 activated both GIP and GLP-1 receptor signaling in vitro and showed glucose-dependent insulin secretion and improved glucose tolerance by acting on both GIP and GLP-1 receptors in mice. With chronic administration to mice, LY3298176 potently decreased body weight and food intake; these effects were significantly greater than the effects of a GLP-1 receptor agonist. A total of 142 human subjects received at least 1 dose of LY3298176, dulaglutide, or placebo. The PK profile of LY3298176 was investigated over a wide dose range (0.25-15 mg) and supports once-weekly administration. In the Phase 1 b trial of diabetic subjects, LY3298176 doses of 10 mg and 15 mg significantly reduced fasting serum glucose compared to placebo (least square mean [LSM] difference [95% CI]: -49.12 mg/dL [-78.14, -20.12] and -43.15 mg/dL [-73.06, -13.21], respectively). Reductions in body weight were significantly greater with the LY3298176 1.5 mg, 4.5 mg and 10 mg doses versus placebo in MAD HS (LSM difference [95% CI]: -1.75 kg [-3.38, -0.12], -5.09 kg [-6.72, -3.46] and -4.61 kg [-6.21, -3.01], respectively) and doses of 10 mg and 15 mg had a relevant effect in T2DM patients (LSM difference [95% CI]: -2.62 kg [-3.79, -1.45] and -2.07 kg [-3.25, -0.88], respectively. The most frequent side effects reported with LY3298176 were gastrointestinal (vomiting, nausea, decreased appetite, diarrhoea, and abdominal distension) in both HS and patients with T2DM; all were dose-dependent and considered mild to moderate in severity.\n\nConclusions: Based on these results, the pharmacology of LY3298176 translates from preclinical to clinical studies. LY3298176 has the potential to deliver clinically meaningful improvement in glycaemic control and body weight. The data warrant further clinical evaluation of LY3298176 for the treatment of T2DM and potentially obesity. [3] Tirzepatide is a single peptide engineered by integrating GLP-1 activity into the GIP sequence. It is described as an "imbalanced and biased" dual agonist. The imbalance refers to its stronger affinity and potency at the GIPR compared to the GLP-1R. The bias refers to its signaling profile at the GLP-1R, where it preferentially activates the cAMP pathway over β-arrestin recruitment, unlike the native ligand GLP-1. [2] The biased agonism at the GLP-1R results in reduced GLP-1R internalization compared to GLP-1. Ex vivo perfusion of pancreatic islets from Arrb1βcell-/- mice showed that deletion of β-arrestin1 enhanced the insulin secretory response to GLP-1 but not to GIP or Tirzepatide, suggesting that the biased signaling of Tirzepatide at the GLP-1R may enhance its insulinotropic effect by avoiding β-arrestin-mediated limitation. [2] The promising clinical efficacy of Tirzepatide is hypothesized to result from the combination of: 1) Full and potent GIPR agonism, 2) Imbalanced engagement favoring the GIPR, allowing higher dosing with potentially better tolerability, and 3) Biased signaling at the GLP-1R that may lead to enhanced insulin secretion. [2] Tirzepatide is under development for the treatment of type 2 diabetes mellitus (T2DM), obesity, and nonalcoholic steatohepatitis (NASH). [2]

Solubility Data

Solubility (In Vitro)

May dissolve in DMSO (in most cases), if not, try other solvents such as H2O, Ethanol, or DMF with a minute amount of products to avoid loss of samples

Solubility (In Vivo)

Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples. Injection Formulations (e.g. IP/IV/IM/SC) Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline) *Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution. Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline) Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil) Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals). Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)] *Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution. Injection Formulation 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (i.e. 500 μL 2-Hydroxypropyl-β-cyclodextrin → 500 μL Saline) Injection Formulation 6: DMSO : PEG300 : castor oil : Saline = 5 : 10 : 20 : 65 (i.e. 50 μL DMSO → 100 μLPEG300 → 200 μL castor oil → 650 μL Saline) Injection Formulation 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (i.e. 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline) Injection Formulation 8: Dissolve in Cremophor/Ethanol (50 : 50), then diluted by Saline Injection Formulation 9: EtOH : Corn oil = 10 : 90 (i.e. 100 μL EtOH → 900 μL Corn oil) Injection Formulation 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL EtOH → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline) Oral Formulations Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium) Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals). Oral Formulation 3: Dissolved in PEG400 Oral Formulation 4: Suspend in 0.2% Carboxymethyl cellulose Oral Formulation 5: Dissolve in 0.25% Tween 80 and 0.5% Carboxymethyl cellulose Oral Formulation 6: Mixing with food powders Note: Please be aware that the above formulations are for reference only. InvivoChem strongly recommends customers to read literature methods/protocols carefully before determining which formulation you should use for in vivo studies, as different compounds have different solubility properties and have to be formulated differently.  (Please use freshly prepared in vivo formulations for optimal results.)