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content-assay

Quantified content: how many milligrams of peptide are actually in the vial, measured against a calibrated reference standard. A separate test from purity, usually a separate line item, and the one that answers the question people think purity answers.

438 questions · sorted by votes · page 1 of 19

41 votes5 answers70k views
What counter-ion should I expect on an SGN retatrutide lot?

Numbers first: SGN · retatrutide. I can parse the result. I am less sure what it licenses me to conclude. I have deliberately not looked at anyone else’s…

acetate-content
acetate-content

Counter-ion content, most often acetate or trifluoroacetate, and why it matters: the counter-ion and residual water are part of the gross mass you…

87 questions
purity
purity

Purity as chromatographic area per cent - the fraction of detected material that is your target peak. It says nothing about how much material is…

788 questions
content-assay
content-assay

Quantified content: how many milligrams of peptide are actually in the vial, measured against a calibrated reference standard. A separate test…

438 questions
asked by leah_ferrers 15k · 2.3 years ago
41 votes5 answers65k views
Is peptide mapping worth paying for on top of a purity figure for ecnoglutide?

For reference: peptide mapping · ecnoglutide. I would like to define my thresholds before I have a result, for obvious reasons. I want a plan with explicit stopping…

content-assay
content-assay

Quantified content: how many milligrams of peptide are actually in the vial, measured against a calibrated reference standard. A separate test…

438 questions
batch-testing
batch-testing

Testing at the batch or lot level: sampling plans, how many vials from a lot need testing to say anything about the lot, and the difference…

865 questions
cost-analysis
cost-analysis

Cost arithmetic done honestly: cost per milligram after dead-space loss, list versus net price, comparing a multi-dose vial to a fixed-dose pen,…

261 questions
asked by p_mkhize 41k · 20 months ago
41 votes0 answers65k views
What counter-ion should I expect on an MKM semaglutide lot?

For reference: MKM · semaglutide. I want to understand what this actually establishes, as opposed to what it is being used to imply. My concern is that I am being…

acetate-content
acetate-content

Counter-ion content, most often acetate or trifluoroacetate, and why it matters: the counter-ion and residual water are part of the gross mass you…

87 questions
purity
purity

Purity as chromatographic area per cent - the fraction of detected material that is your target peak. It says nothing about how much material is…

788 questions
content-assay
content-assay

Quantified content: how many milligrams of peptide are actually in the vial, measured against a calibrated reference standard. A separate test…

438 questions
asked by sinead_gaffney 14k · 2.3 years ago
41 votes0 answers48k views
Does racemisation of dulaglutide at 40 °C show up as a loss of content or of purity?

Numbers first: racemisation · dulaglutide · 40 °C. I can predict the outcome but I cannot explain it, which means I will get the next case wrong. I would like to know…

peptide-stability
peptide-stability

The chemistry of peptide degradation: deamidation, oxidation, hydrolysis, aggregation and fibrillation, and how temperature, pH, ionic strength,…

832 questions
content-assay
content-assay

Quantified content: how many milligrams of peptide are actually in the vial, measured against a calibrated reference standard. A separate test…

438 questions
purity
purity

Purity as chromatographic area per cent - the fraction of detected material that is your target peak. It says nothing about how much material is…

788 questions
asked by cake_intact 18k · 21 months ago
41 votes5 answers33k views
Does a GLP-1 receptor agonist adsorb measurably to the vial wall at 4 mg/mL?

Details up front: a GLP-1 receptor agonist · 4 mg/mL. I can do the algebra. I am not confident about the conversion factors. If there is a standard way to lay this…

peptide-stability
peptide-stability

The chemistry of peptide degradation: deamidation, oxidation, hydrolysis, aggregation and fibrillation, and how temperature, pH, ionic strength,…

832 questions
content-assay
content-assay

Quantified content: how many milligrams of peptide are actually in the vial, measured against a calibrated reference standard. A separate test…

438 questions
storage
storage

Storage conditions and their evidence base: minus twenty degrees for powder, refrigerated for solution, protection from light, and what the…

646 questions
asked by sinead_gaffney 14k · 2.0 years ago
40 votes 4 answers68k views
Does survodutide adsorb measurably to the vial wall at 20 mg/mL?

The case in front of me: survodutide · 20 mg/mL. I want the working, not the result — I need to be able to redo it with different numbers. I care about the precision…

peptide-stability
peptide-stability

The chemistry of peptide degradation: deamidation, oxidation, hydrolysis, aggregation and fibrillation, and how temperature, pH, ionic strength,…

832 questions
content-assay
content-assay

Quantified content: how many milligrams of peptide are actually in the vial, measured against a calibrated reference standard. A separate test…

438 questions
storage
storage

Storage conditions and their evidence base: minus twenty degrees for powder, refrigerated for solution, protection from light, and what the…

646 questions
asked by mg_per_ml 12k · 2.3 years ago
40 votes 3 answers59k views
Would you accept 98.8% on liraglutide from FGP without a content assay?

The case in front of me: 98.8% · liraglutide · FGP. The failure mode I am trying to avoid is making this decision emotionally. I have twelve months in view and I…

purity
purity

Purity as chromatographic area per cent - the fraction of detected material that is your target peak. It says nothing about how much material is…

788 questions
content-assay
content-assay

Quantified content: how many milligrams of peptide are actually in the vial, measured against a calibrated reference standard. A separate test…

438 questions
vendor-vetting
vendor-vetting

Evaluating a supplier on evidence rather than reputation: testing history across batches, whether certificates are batch-specific, how failures…

436 questions
asked by Dr_Ilse_Vandenberg 78k · 2.0 years ago
40 votes 5 answers42k views
Does aggregation of cagrilintide at room temperature show up as a loss of content or of purity?

Setup, so nobody has to ask: aggregation · cagrilintide · room temperature. The empirical answer seems settled. The explanation does not. If the honest answer is that…

peptide-stability
peptide-stability

The chemistry of peptide degradation: deamidation, oxidation, hydrolysis, aggregation and fibrillation, and how temperature, pH, ionic strength,…

832 questions
content-assay
content-assay

Quantified content: how many milligrams of peptide are actually in the vial, measured against a calibrated reference standard. A separate test…

438 questions
purity
purity

Purity as chromatographic area per cent - the fraction of detected material that is your target peak. It says nothing about how much material is…

788 questions
asked by grainne_ahearn 13k · 22 months ago
39 votes5 answers60k views
Why did two SSA lots of semaglutide differ on content assay?

The particulars: SSA · semaglutide. An unexpected observation, and I would like a differential rather than reassurance. The conditions were within what I understood…

batch-testing
batch-testing

Testing at the batch or lot level: sampling plans, how many vials from a lot need testing to say anything about the lot, and the difference…

865 questions
content-assay
content-assay

Quantified content: how many milligrams of peptide are actually in the vial, measured against a calibrated reference standard. A separate test…

438 questions
vendor-vetting
vendor-vetting

Evaluating a supplier on evidence rather than reputation: testing history across batches, whether certificates are batch-specific, how failures…

436 questions
asked by bridget_nyathi 16k · 20 months ago
39 votes 5 answers24k views
Would you accept 95.2% on retatrutide from MKM without a content assay?

Numbers first: 95.2% · retatrutide · MKM. I would rather over-plan the first cycle and simplify later. I am prepared to do the work if someone can tell me which work…

purity
purity

Purity as chromatographic area per cent - the fraction of detected material that is your target peak. It says nothing about how much material is…

788 questions
content-assay
content-assay

Quantified content: how many milligrams of peptide are actually in the vial, measured against a calibrated reference standard. A separate test…

438 questions
vendor-vetting
vendor-vetting

Evaluating a supplier on evidence rather than reputation: testing history across batches, whether certificates are batch-specific, how failures…

436 questions
asked by mala_venkatesh 21k · 2.0 years ago
38 votes 5 answers75k views
Would you accept 96.4% on a GLP-1 receptor agonist from QST without a content assay?

Setup, so nobody has to ask: 96.4% · a GLP-1 receptor agonist · QST. I would like to set this up properly once, rather than adjust it repeatedly. My budget is real…

purity
purity

Purity as chromatographic area per cent - the fraction of detected material that is your target peak. It says nothing about how much material is…

788 questions
content-assay
content-assay

Quantified content: how many milligrams of peptide are actually in the vial, measured against a calibrated reference standard. A separate test…

438 questions
vendor-vetting
vendor-vetting

Evaluating a supplier on evidence rather than reputation: testing history across batches, whether certificates are batch-specific, how failures…

436 questions
asked by seven_day_half 16k · 2.1 years ago
38 votes5 answers51k views
Would you accept 99.4% on orforglipron from SSA without a content assay?

What I have: 99.4% · orforglipron · SSA. This is a planning question. I know what my options are; I do not know how to weigh them. What I want is the minimum viable…

purity
purity

Purity as chromatographic area per cent - the fraction of detected material that is your target peak. It says nothing about how much material is…

788 questions
content-assay
content-assay

Quantified content: how many milligrams of peptide are actually in the vial, measured against a calibrated reference standard. A separate test…

438 questions
vendor-vetting
vendor-vetting

Evaluating a supplier on evidence rather than reputation: testing history across batches, whether certificates are batch-specific, how failures…

436 questions
asked by lukas_sedlacek 17k · 17 months ago
38 votes 5 answers47k views
Would you accept 98.4% on a GLP-1 receptor agonist from HJ without a content assay?

Setup, so nobody has to ask: 98.4% · a GLP-1 receptor agonist · HJ. I am trying to build something sustainable rather than something thorough that I will abandon. I…

purity
purity

Purity as chromatographic area per cent - the fraction of detected material that is your target peak. It says nothing about how much material is…

788 questions
content-assay
content-assay

Quantified content: how many milligrams of peptide are actually in the vial, measured against a calibrated reference standard. A separate test…

438 questions
vendor-vetting
vendor-vetting

Evaluating a supplier on evidence rather than reputation: testing history across batches, whether certificates are batch-specific, how failures…

436 questions
asked by fiadh_cronin 14k · 18 months ago
38 votes 3 answers42k views
Why did two BCH lots of cagrilintide differ on content assay?

Stated plainly: BCH · cagrilintide. I noticed this today and I have not touched anything since, in case the state is diagnostic. I have not discarded anything yet, so…

batch-testing
batch-testing

Testing at the batch or lot level: sampling plans, how many vials from a lot need testing to say anything about the lot, and the difference…

865 questions
content-assay
content-assay

Quantified content: how many milligrams of peptide are actually in the vial, measured against a calibrated reference standard. A separate test…

438 questions
vendor-vetting
vendor-vetting

Evaluating a supplier on evidence rather than reputation: testing history across batches, whether certificates are batch-specific, how failures…

436 questions
asked by Dr_Jonas_Halvorsen 41k · 22 months ago
38 votes0 answers22k views
Does orforglipron adsorb measurably to the vial wall at 2 mg/mL?

Setup, so nobody has to ask: orforglipron · 2 mg/mL. I have worked this out and I would like someone to find the error, because I suspect there is one. My working so…

peptide-stability
peptide-stability

The chemistry of peptide degradation: deamidation, oxidation, hydrolysis, aggregation and fibrillation, and how temperature, pH, ionic strength,…

832 questions
content-assay
content-assay

Quantified content: how many milligrams of peptide are actually in the vial, measured against a calibrated reference standard. A separate test…

438 questions
storage
storage

Storage conditions and their evidence base: minus twenty degrees for powder, refrigerated for solution, protection from light, and what the…

646 questions
asked by nadia_kowalczyk 14k · 21 months ago
37 votes 5 answers64k views
Why did two GGPeps lots of survodutide differ on content assay?

The particulars: GGPeps · survodutide. An unexpected observation, and I would like a differential rather than reassurance. The conditions were within what I…

batch-testing
batch-testing

Testing at the batch or lot level: sampling plans, how many vials from a lot need testing to say anything about the lot, and the difference…

865 questions
content-assay
content-assay

Quantified content: how many milligrams of peptide are actually in the vial, measured against a calibrated reference standard. A separate test…

438 questions
vendor-vetting
vendor-vetting

Evaluating a supplier on evidence rather than reputation: testing history across batches, whether certificates are batch-specific, how failures…

436 questions
asked by mass_shift_18 14k · 2.2 years ago
37 votes5 answers39k views
Why did two FGP lots of cagrilintide differ on content assay?

Stated plainly: FGP · cagrilintide. This is not behaving the way I expected and I want to understand the discrepancy before I act on it. I have photographed the…

batch-testing
batch-testing

Testing at the batch or lot level: sampling plans, how many vials from a lot need testing to say anything about the lot, and the difference…

865 questions
content-assay
content-assay

Quantified content: how many milligrams of peptide are actually in the vial, measured against a calibrated reference standard. A separate test…

438 questions
vendor-vetting
vendor-vetting

Evaluating a supplier on evidence rather than reputation: testing history across batches, whether certificates are batch-specific, how failures…

436 questions
asked by vial_five 15k · 17 months ago
37 votes 5 answers33k views
Does a large published testing history at KP imply lot consistency?

This is my second independent submission on material from the same supplier. I suspect the usual explanation for this is wrong, or at least incomplete. I am aware…

batch-testing
batch-testing

Testing at the batch or lot level: sampling plans, how many vials from a lot need testing to say anything about the lot, and the difference…

865 questions
vendor-vetting
vendor-vetting

Evaluating a supplier on evidence rather than reputation: testing history across batches, whether certificates are batch-specific, how failures…

436 questions
content-assay
content-assay

Quantified content: how many milligrams of peptide are actually in the vial, measured against a calibrated reference standard. A separate test…

438 questions
asked by ahmed_zerouali 19k · 2.2 years ago
37 votes0 answers26k views
Why did two MKM lots of survodutide differ on content assay?

The specifics, since they change the answer: MKM · survodutide. An unexpected observation, and I would like a differential rather than reassurance. The conditions…

batch-testing
batch-testing

Testing at the batch or lot level: sampling plans, how many vials from a lot need testing to say anything about the lot, and the difference…

865 questions
content-assay
content-assay

Quantified content: how many milligrams of peptide are actually in the vial, measured against a calibrated reference standard. A separate test…

438 questions
vendor-vetting
vendor-vetting

Evaluating a supplier on evidence rather than reputation: testing history across batches, whether certificates are batch-specific, how failures…

436 questions
asked by rukhsana_iqbal 14k · 2.0 years ago
37 votes 2 answers21k views
Does cagrilintide adsorb measurably to the vial wall at 6.67 mg/mL?

What I have: cagrilintide · 6.67 mg/mL. This should be a straightforward calculation and I keep getting two different answers. The numbers are arbitrary; the method…

peptide-stability
peptide-stability

The chemistry of peptide degradation: deamidation, oxidation, hydrolysis, aggregation and fibrillation, and how temperature, pH, ionic strength,…

832 questions
content-assay
content-assay

Quantified content: how many milligrams of peptide are actually in the vial, measured against a calibrated reference standard. A separate test…

438 questions
storage
storage

Storage conditions and their evidence base: minus twenty degrees for powder, refrigerated for solution, protection from light, and what the…

646 questions
asked by eoin_mcgarry 16k · 2.2 years ago
37 votes0 answers18k views
Does fibrillation of semaglutide at 30 °C show up as a loss of content or of purity?

The particulars: fibrillation · semaglutide · 30 °C. I would like the mechanism, because I want to be able to reason about the cases nobody has written about. I have…

peptide-stability
peptide-stability

The chemistry of peptide degradation: deamidation, oxidation, hydrolysis, aggregation and fibrillation, and how temperature, pH, ionic strength,…

832 questions
content-assay
content-assay

Quantified content: how many milligrams of peptide are actually in the vial, measured against a calibrated reference standard. A separate test…

438 questions
purity
purity

Purity as chromatographic area per cent - the fraction of detected material that is your target peak. It says nothing about how much material is…

788 questions
asked by g_paskevicius 44k · 23 months ago
36 votes 5 answers68k views
Does ecnoglutide adsorb measurably to the vial wall at 20 mg/mL?

The case in front of me: ecnoglutide · 20 mg/mL. I want the working, not the result — I need to be able to redo it with different numbers. I care about the precision…

peptide-stability
peptide-stability

The chemistry of peptide degradation: deamidation, oxidation, hydrolysis, aggregation and fibrillation, and how temperature, pH, ionic strength,…

832 questions
content-assay
content-assay

Quantified content: how many milligrams of peptide are actually in the vial, measured against a calibrated reference standard. A separate test…

438 questions
storage
storage

Storage conditions and their evidence base: minus twenty degrees for powder, refrigerated for solution, protection from light, and what the…

646 questions
asked by assay_blank 39k · 2.2 years ago
36 votes 5 answers48k views
How do I read a Karl Fischer water content result on a lyophilised vial?

The method section is present, which is unusual enough that I want to make use of it. I would like to know the limits of what can be inferred from this. What I am…

water-content
water-content

Residual moisture in a lyophilised solid, measured by Karl Fischer titration or loss on drying. It drives both the mass balance on a content assay…

39 questions
lyophilisation
lyophilisation

Freeze-drying: primary and secondary drying, collapse temperature, the role of bulking agents and cryoprotectants such as mannitol and trehalose,…

17 questions
content-assay
content-assay

Quantified content: how many milligrams of peptide are actually in the vial, measured against a calibrated reference standard. A separate test…

438 questions
asked by fresh_bac 13k · 2.3 years ago
36 votes5 answers45k views
Would you accept 95.2% on liraglutide from ERP without a content assay?

Concretely: 95.2% · liraglutide · ERP. I want to decide this in advance so that I am not deciding it under pressure later. Assume I will follow the plan I write down,…

purity
purity

Purity as chromatographic area per cent - the fraction of detected material that is your target peak. It says nothing about how much material is…

788 questions
content-assay
content-assay

Quantified content: how many milligrams of peptide are actually in the vial, measured against a calibrated reference standard. A separate test…

438 questions
vendor-vetting
vendor-vetting

Evaluating a supplier on evidence rather than reputation: testing history across batches, whether certificates are batch-specific, how failures…

436 questions
asked by oona_kekkonen 16k · 23 months ago
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