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Unanswered questions

Questions with no answer at all. Not questions with no accepted answer — those are elsewhere.

739 questions · page 15 of 31

28 votes0 answers14k views
What is the reported incidence of early satiety on semaglutide in STEP 1?

Concretely: early satiety · semaglutide · STEP 1. I would like to know the limits of what can be inferred from this. What I am trying to avoid is over-reading a…

gi-side-effects
gi-side-effects

The gastrointestinal cluster as a whole - nausea, vomiting, diarrhoea, constipation, reflux, early satiety - with trial incidence rates, dropout…

162 questions
clinical-trials
clinical-trials

Reading the primary literature properly: estimands, intention-to-treat versus per-protocol, confidence intervals, absolute versus relative…

745 questions
semaglutide
semaglutide

A GLP-1 receptor agonist with a fatty-acid-acylated backbone and a roughly one-week half-life, marketed for type 2 diabetes and for weight…

470 questions
asked by swirl_dont_shake 10k · 13 months ago
12 votes0 answers3.4k views
Has anyone independently verified an MKM semaglutide batch COA?

The case in front of me: MKM · semaglutide. Somebody stated this to me confidently and I would like to check it before repeating it. I would accept a well-reasoned…

vendor-vetting
vendor-vetting

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

454 questions
coa
coa

Certificates of analysis: what fields a useful one carries, how to tell a real analytical report from a marketing document, batch and lot…

771 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…

910 questions
semaglutide
semaglutide

A GLP-1 receptor agonist with a fatty-acid-acylated backbone and a roughly one-week half-life, marketed for type 2 diabetes and for weight…

470 questions
asked by ten_mg_vial 31k · 13 months ago
28 votes0 answers22k views
Is magnesium worth drawing at baseline before starting tirzepatide?

The particulars: magnesium · tirzepatide. 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…

bloodwork
bloodwork

Laboratory monitoring: which panels are worth ordering, sensible intervals, reference-range versus optimal-range arguments, and how to read a…

296 questions
harm-reduction
harm-reduction

Reducing avoidable risk where a decision has already been made: independent verification before use, sterility practice, dose arithmetic checked…

472 questions
a1c
a1c

Glycated haemoglobin as a ninety-day glycaemic average: what a change of half a point means, why it lags, and the conditions under which it…

122 questions
electrolytes
electrolytes

Sodium, potassium and magnesium during reduced intake and GI losses: what the symptoms of a shortfall look like, when a panel is worth drawing,…

72 questions
tirzepatide
tirzepatide

A dual GIP and GLP-1 receptor agonist. Questions here cover the SURPASS and SURMOUNT programmes, the practical differences from a pure GLP-1…

370 questions
asked by forty_two_c 66k · 13 months ago
19 votes0 answers12k views
Is a Karl Fischer water content test worth paying for on top of a purity figure for liraglutide?

The case in front of me: a Karl Fischer water content test · liraglutide. I want to decide this in advance so that I am not deciding it under pressure later. Assume I…

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…

476 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…

910 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,…

260 questions
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…

51 questions
liraglutide
liraglutide

A once-daily GLP-1 receptor agonist and the compound that established the class. Still relevant for its shorter half-life, its paediatric and…

235 questions
asked by anouk_desmet 16k · 13 months ago
13 votes0 answers3.6k views
What is the thermal exposure on a Suzhou to the United States lane in summer?

Details up front: Suzhou · the United States. I have read the primary source rather than the summary, which has left me with more questions. I understand the…

cold-chain
cold-chain

Keeping material within a temperature window from manufacture to use: phase-change packs versus dry ice, thermal mass, transit-lane temperature…

578 questions
international-shipping
international-shipping

Cross-border movement of research material: transit lanes and their thermal profiles, tracked versus untracked, declaration accuracy, and what…

471 questions
storage
storage

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

701 questions
asked by samir_bennani 15k · 13 months ago
34 votes0 answers21k views
Does a phase-change pack hold a tirzepatide shipment for forty-two days in transit?

What I am working with: tirzepatide · forty-two days. I would rather understand the derivation than memorise the outcome. Two people I asked gave two answers that…

cold-chain
cold-chain

Keeping material within a temperature window from manufacture to use: phase-change packs versus dry ice, thermal mass, transit-lane temperature…

578 questions
international-shipping
international-shipping

Cross-border movement of research material: transit lanes and their thermal profiles, tracked versus untracked, declaration accuracy, and what…

471 questions
storage
storage

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

701 questions
tirzepatide
tirzepatide

A dual GIP and GLP-1 receptor agonist. Questions here cover the SURPASS and SURMOUNT programmes, the practical differences from a pure GLP-1…

370 questions
asked by n_takahashi 29k · 13 months ago
27 votes0 answers13k views
How do I read an impurity table on a liraglutide certificate against the 99.1% headline?

The particulars: liraglutide · 99.1%. I would rather understand the derivation than memorise the outcome. Two people I asked gave two answers that differ by a factor…

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…

833 questions
coa
coa

Certificates of analysis: what fields a useful one carries, how to tell a real analytical report from a marketing document, batch and lot…

771 questions
hplc
hplc

Reverse-phase high-performance liquid chromatography, the workhorse purity method. Column chemistry, mobile-phase choice, gradient slope,…

503 questions
liraglutide
liraglutide

A once-daily GLP-1 receptor agonist and the compound that established the class. Still relevant for its shorter half-life, its paediatric and…

235 questions
asked by vial_five 12k · 13 months ago
23 votes0 answers19k views
How does the reference standard error propagate into my content figure?

I am comparing a supplier certificate against an independent result on the same lot. I have worked this out and I would like someone to find the error, because I…

reference-standard
reference-standard

Certified reference materials and in-house standards: traceability, the certificate of the standard itself, system suitability, and why every…

185 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…

476 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…

833 questions
asked by ivo_paunovic 16k · 13 months ago
19 votes0 answers14k views
Is STEP 3 a fair comparison of semaglutide against its comparator arm?

Stated plainly: STEP 3 · semaglutide. This is asserted often enough that I assumed it was established, and then I went looking for the source. I have searched the…

clinical-trials
clinical-trials

Reading the primary literature properly: estimands, intention-to-treat versus per-protocol, confidence intervals, absolute versus relative…

745 questions
semaglutide
semaglutide

A GLP-1 receptor agonist with a fatty-acid-acylated backbone and a roughly one-week half-life, marketed for type 2 diabetes and for weight…

470 questions
tirzepatide
tirzepatide

A dual GIP and GLP-1 receptor agonist. Questions here cover the SURPASS and SURMOUNT programmes, the practical differences from a pure GLP-1…

370 questions
asked by Dr_Signe_Baldursdottir 29k · 13 months ago
28 votes0 answers25k views
Can I reconstitute orforglipron at 2 mg/mL and still measure a small dose accurately?

Setup, so nobody has to ask: orforglipron · 2 mg/mL. I would like to set this up properly once, rather than adjust it repeatedly. My budget is real but not tight, and…

diluent-volume
diluent-volume

Choosing how much diluent to add, which is really a question about what you want your measurement resolution to be. Larger volumes buy you…

295 questions
insulin-syringe
insulin-syringe

U-100 and U-40 insulin syringes as measuring instruments. A U-100 syringe is graduated in insulin units where 100 units equals 1 mL, so one unit…

244 questions
dosing-math
dosing-math

The arithmetic itself: milligrams to millilitres to insulin units, concentration after reconstitution, dose per draw, and vial-days per vial. Show…

764 questions
orforglipron
orforglipron

A non-peptide, orally bioavailable small-molecule GLP-1 receptor agonist studied in the ATTAIN programme. It is not a peptide, which changes…

219 questions
asked by kelvin_lam 7.6k · 13 months ago
28 votes0 answers17k views
What does 95.2% purity on a C18 column actually tell me about a semaglutide vial?

Stated plainly: 95.2% · a C18 column · semaglutide. I have read the primary source rather than the summary, which has left me with more questions. I understand the…

hplc
hplc

Reverse-phase high-performance liquid chromatography, the workhorse purity method. Column chemistry, mobile-phase choice, gradient slope,…

503 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…

833 questions
coa
coa

Certificates of analysis: what fields a useful one carries, how to tell a real analytical report from a marketing document, batch and lot…

771 questions
semaglutide
semaglutide

A GLP-1 receptor agonist with a fatty-acid-acylated backbone and a roughly one-week half-life, marketed for type 2 diabetes and for weight…

470 questions
asked by pascal_thibault 11k · 13 months ago
22 votes0 answers15k views
Is vomiting on orforglipron dose-dependent or dose-rate dependent?

What I have: vomiting · orforglipron. I can predict the outcome but I cannot explain it, which means I will get the next case wrong. I would like to know how…

vomiting
vomiting

Emesis as a reported adverse event: trial incidence, its relationship to dose escalation rate, dehydration risk, and when it stops being a…

57 questions
titration
titration

Stepwise dose increases over weeks, why the label schedules exist at all, and what tolerability-driven deviation from a schedule looks like in…

456 questions
orforglipron
orforglipron

A non-peptide, orally bioavailable small-molecule GLP-1 receptor agonist studied in the ATTAIN programme. It is not a peptide, which changes…

219 questions
asked by samir_bennani 15k · 13 months ago
24 votes0 answers16k views
How many units on a 1 mL luer-lock syringe is a 2.5 mg dose at 3.33 mg/mL?

For reference: a 1 mL luer-lock syringe · 2.5 mg · 3.33 mg/mL. I would rather understand the derivation than memorise the outcome. Two people I asked gave two answers…

dosing-math
dosing-math

The arithmetic itself: milligrams to millilitres to insulin units, concentration after reconstitution, dose per draw, and vial-days per vial. Show…

764 questions
insulin-syringe
insulin-syringe

U-100 and U-40 insulin syringes as measuring instruments. A U-100 syringe is graduated in insulin units where 100 units equals 1 mL, so one unit…

244 questions
reconstitution
reconstitution

Taking a lyophilised vial to a solution of known concentration: choice of diluent, volume selection, how to add liquid without shearing the cake,…

313 questions
asked by amara_nwachukwu 20k · 13 months ago
3 votes0 answers2.4k views
Is albumin-to-creatinine ratio a better monitoring choice than GGT on tirzepatide?

For reference: albumin-to-creatinine ratio · GGT · tirzepatide. I have used one of these for a while and I am considering switching, which requires a reason. What I…

bloodwork
bloodwork

Laboratory monitoring: which panels are worth ordering, sensible intervals, reference-range versus optimal-range arguments, and how to read a…

296 questions
kidney-function
kidney-function

eGFR, creatinine, cystatin C and albuminuria: the acute haemodynamic dip that is not injury, the renal outcome data from the FLOW programme, and…

141 questions
lipids
lipids

Lipid response on treatment: triglycerides, LDL-C, non-HDL-C, ApoB and Lp(a), which of them move with weight loss, and why a fasting panel drawn…

139 questions
liver-enzymes
liver-enzymes

ALT, AST, GGT and ALP: what they do and do not indicate about hepatic fat, why enzymes are a poor surrogate for histology, and where non-invasive…

91 questions
tirzepatide
tirzepatide

A dual GIP and GLP-1 receptor agonist. Questions here cover the SURPASS and SURMOUNT programmes, the practical differences from a pure GLP-1…

370 questions
asked by sample_id 17k · 13 months ago
27 votes0 answers12k views
Does racemisation dominate for orforglipron held at minus 20 °C?

Numbers first: racemisation · orforglipron · minus 20 °C. I suspect the usual explanation for this is wrong, or at least incomplete. I am aware this may have a boring…

peptide-stability
peptide-stability

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

908 questions
storage
storage

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

701 questions
hplc
hplc

Reverse-phase high-performance liquid chromatography, the workhorse purity method. Column chemistry, mobile-phase choice, gradient slope,…

503 questions
orforglipron
orforglipron

A non-peptide, orally bioavailable small-molecule GLP-1 receptor agonist studied in the ATTAIN programme. It is not a peptide, which changes…

219 questions
asked by meniscus_film 32k · 13 months ago
30 votes0 answers14k views
What interval makes sense for repeating GGT on oral semaglutide?

Details up front: GGT · oral semaglutide. 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…

bloodwork
bloodwork

Laboratory monitoring: which panels are worth ordering, sensible intervals, reference-range versus optimal-range arguments, and how to read a…

296 questions
harm-reduction
harm-reduction

Reducing avoidable risk where a decision has already been made: independent verification before use, sterility practice, dose arithmetic checked…

472 questions
a1c
a1c

Glycated haemoglobin as a ninety-day glycaemic average: what a change of half a point means, why it lags, and the conditions under which it…

122 questions
liver-enzymes
liver-enzymes

ALT, AST, GGT and ALP: what they do and do not indicate about hepatic fat, why enzymes are a poor surrogate for histology, and where non-invasive…

91 questions
oral-glp1
oral-glp1

Oral routes for GLP-1 receptor agonism: peptide formulations rescued by absorption enhancers such as SNAC, and true small molecules that need no…

219 questions
asked by yuki_morishita 10k · 13 months ago
25 votes0 answers9.5k views
What does STEP 4 tell me about fatigue at the 1 mg dose?

Conditions: STEP 4 · fatigue · 1 mg. The figures are clear enough; the question is what they mean and what they do not. I can supply the numbers if the specifics…

clinical-trials
clinical-trials

Reading the primary literature properly: estimands, intention-to-treat versus per-protocol, confidence intervals, absolute versus relative…

745 questions
fatigue
fatigue

Tiredness on treatment: how much is energy deficit, how much is dehydration or electrolyte drift, how much is genuinely drug-attributable, and…

78 questions
titration
titration

Stepwise dose increases over weeks, why the label schedules exist at all, and what tolerability-driven deviation from a schedule looks like in…

456 questions
asked by cake_collapsed 14k · 13 months ago
8 votes0 answers6.9k views
Would you accept 96.4% on semaglutide from KP without a content assay?

The particulars: 96.4% · semaglutide · KP. I am at the decision point and I would rather think it through than improvise. I would rather spend money on measurement…

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…

833 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…

476 questions
vendor-vetting
vendor-vetting

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

454 questions
semaglutide
semaglutide

A GLP-1 receptor agonist with a fatty-acid-acylated backbone and a roughly one-week half-life, marketed for type 2 diabetes and for weight…

470 questions
asked by anders_vestby 8.5k · 13 months ago
2 votes0 answers2.4k views
How long does ecnoglutide stay within specification at room temperature once reconstituted?

The specifics, since they change the answer: ecnoglutide · room temperature. I have done this once and I suspect I got away with it rather than got it right. For…

peptide-stability
peptide-stability

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

908 questions
storage
storage

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

701 questions
shelf-life
shelf-life

How long a preparation remains within specification: labelled expiry for a sealed lyophilised vial, beyond-use dating after reconstitution, and…

327 questions
ecnoglutide
ecnoglutide

A long-acting GLP-1 receptor agonist with a cAMP-biased signalling profile. A niche tag, mostly used for mechanism questions about biased agonism…

223 questions
asked by marta_szymanska 10k · 14 months ago
4 votes0 answers4.2k views
How many units on a 0.5 mL insulin syringe is a 2 mg dose at 6.67 mg/mL?

Concretely: a 0.5 mL insulin syringe · 2 mg · 6.67 mg/mL. Please show the division. I want to check my own against yours. I would like the general form as well as the…

dosing-math
dosing-math

The arithmetic itself: milligrams to millilitres to insulin units, concentration after reconstitution, dose per draw, and vial-days per vial. Show…

764 questions
insulin-syringe
insulin-syringe

U-100 and U-40 insulin syringes as measuring instruments. A U-100 syringe is graduated in insulin units where 100 units equals 1 mL, so one unit…

244 questions
reconstitution
reconstitution

Taking a lyophilised vial to a solution of known concentration: choice of diluent, volume selection, how to add liquid without shearing the cake,…

313 questions
asked by nadia_kowalczyk 20k · 14 months ago
3 votes0 answers3.2k views
Is a 97.9% result from PeptideMeter comparable to 97.6% from Janoshik?

The specifics, since they change the answer: 97.9% · PeptideMeter · 97.6% · Janoshik. The comparison I want does not seem to exist anywhere in a form I can evaluate.…

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…

833 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…

910 questions
reference-standard
reference-standard

Certified reference materials and in-house standards: traceability, the certificate of the standard itself, system suitability, and why every…

185 questions
peptidemeter
peptidemeter

PeptideMeter, an independent peptide analytics and vendor-rating service. Use this tag for its published datasets, its rating methodology, and how…

107 questions
janoshik
janoshik

Janoshik Analytical, an independent third-party testing laboratory widely used by this community for HPLC purity, identity and quantified content…

139 questions
asked by swab_stopper 8.8k · 14 months ago
34 votes0 answers12k views
How many weeks to steady state for retatrutide on a weekly schedule?

The receptor pharmacology I can follow; the in vivo translation is where I lose the thread. I have worked this out and I would like someone to find the error, because…

glp1-mechanism
glp1-mechanism

Receptor-level pharmacology: GLP-1R as a class B GPCR, cAMP and PKA signalling, biased agonism, internalisation and resensitisation, and the…

132 questions
titration
titration

Stepwise dose increases over weeks, why the label schedules exist at all, and what tolerability-driven deviation from a schedule looks like in…

456 questions
dosing-math
dosing-math

The arithmetic itself: milligrams to millilitres to insulin units, concentration after reconstitution, dose per draw, and vial-days per vial. Show…

764 questions
retatrutide
retatrutide

An investigational GLP-1, GIP and glucagon receptor tri-agonist, studied in the TRIUMPH programme. Not approved anywhere. Use this tag for…

251 questions
asked by shear_at_the_front 17k · 14 months ago
30 votes0 answers9.1k views
What does 98.8% purity on a C8 column actually tell me about a tirzepatide vial?

Numbers first: 98.8% · a C8 column · tirzepatide. This is presented as though it settles something, and I am not convinced it does. I have two documents that appear…

hplc
hplc

Reverse-phase high-performance liquid chromatography, the workhorse purity method. Column chemistry, mobile-phase choice, gradient slope,…

503 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…

833 questions
coa
coa

Certificates of analysis: what fields a useful one carries, how to tell a real analytical report from a marketing document, batch and lot…

771 questions
tirzepatide
tirzepatide

A dual GIP and GLP-1 receptor agonist. Questions here cover the SURPASS and SURMOUNT programmes, the practical differences from a pure GLP-1…

370 questions
asked by j_wierzbicki 69k · 14 months ago
24 votes0 answers9.1k views
If I reconstitute a 15 mg vial with 1.5 mL of phosphate-buffered diluent, what concentration do I end up with?

The specifics, since they change the answer: 15 mg · 1.5 mL · phosphate-buffered diluent. I would like the arithmetic checked rather than the conclusion asserted. I…

reconstitution
reconstitution

Taking a lyophilised vial to a solution of known concentration: choice of diluent, volume selection, how to add liquid without shearing the cake,…

313 questions
diluent-volume
diluent-volume

Choosing how much diluent to add, which is really a question about what you want your measurement resolution to be. Larger volumes buy you…

295 questions
dosing-math
dosing-math

The arithmetic itself: milligrams to millilitres to insulin units, concentration after reconstitution, dose per draw, and vial-days per vial. Show…

764 questions
asked by thabo_maseko 28k · 14 months ago