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1.4k questions · page 45 of 60

6 votes5 answers3.3k views
What does SURMOUNT-5 tell me about dizziness at the 60 mg dose?

The case in front of me: SURMOUNT-5 · dizziness · 60 mg. I would like to know the limits of what can be inferred from this. What I am trying to avoid is over-reading…

clinical-trials
clinical-trials

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

913 questions
gi-side-effects
gi-side-effects

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

416 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…

444 questions
asked by zainab_mustafa 16k · 8 months ago
6 votes 5 answers3.2k views
What does STEP 3 report at the 10 mg dose level?

Details up front: STEP 3 · 10 mg. This is presented as though it settles something, and I am not convinced it does. I have two documents that appear to disagree,…

clinical-trials
clinical-trials

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

913 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…

811 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…

444 questions
asked by sasha_ferreira 15k · 7 months ago
10 votes 3 answers6.2k views
Can I reconstitute dulaglutide at 2 mg/mL and still measure a small dose accurately?

Stated plainly: dulaglutide · 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 my tolerance…

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…

308 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…

268 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…

811 questions
asked by Dr_Ingrid_Baumgartner 39k · 7 months ago
20 votes 1 answer4.6k views
How many vials from a WWB lot should I send for a Karl Fischer water content test?

Details up front: WWB · a Karl Fischer water content test. I can do the algebra. I am not confident about the conversion factors. If there is a standard way to lay…

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
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…

749 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 noor_alhassan 15k · 6 months ago
17 votes 3 answers14k views
Does the SURMOUNT-1 population resemble anyone asking about cagrilintide here?

What I am working with: SURMOUNT-1 · cagrilintide. I have read the primary source rather than the summary, which has left me with more questions. I understand the…

clinical-trials
clinical-trials

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

913 questions
harm-reduction
harm-reduction

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

445 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…

360 questions
asked by ellis_thorne 17k · 7 months ago
9 votes4 answers9.6k views
Does aspartimide formation dominate for liraglutide held at 25 °C?

The case in front of me: aspartimide formation · liraglutide · 25 °C. I want to know whether this is a real physical effect or an artefact of how it is measured. What…

peptide-stability
peptide-stability

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

832 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
hplc
hplc

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

466 questions
asked by a_lindgren 46k · 7 months ago
24 votes5 answers12k views
How many vial-days does a 2.5 mg vial give at 20 mg/mL on a weekly schedule?

Conditions: 2.5 mg · 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 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…

811 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
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…

308 questions
asked by teodora_ilic 15k · 6 months ago
22 votes 5 answers16k views
What is the arithmetic to convert 30 mg in 2.5 mL into units on a U-100 scale?

Details up front: 30 mg · 2.5 mL. This should be a straightforward calculation and I keep getting two different answers. The numbers are arbitrary; the method is what…

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…

811 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…

268 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,…

330 questions
asked by Dr_Priya_Raghunathan 94k · 7 months ago
7 votes0 answers3.2k views
Why do two papers on FLOW report different headline figures?

I have the full paper rather than the abstract, and the supplementary appendix. I would like the mechanism, because I want to be able to reason about the cases nobody…

clinical-trials
clinical-trials

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

913 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…

811 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…

360 questions
asked by v_ramaswamy 40k · 3 months ago
25 votes 5 answers11k views
Does GGPeps issue lot-specific documentation, or a batch certificate?

I have both a purity figure and a content figure, which is why the discrepancy is visible. I want to understand what this actually establishes, as opposed to what it…

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
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…

749 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 low_dead_space 42k · 7 months ago
17 votes 3 answers5.4k views
What counter-ion should I expect on a Homopeptide liraglutide lot?

Conditions: Homopeptide · liraglutide. The figures are clear enough; the question is what they mean and what they do not. I can supply the numbers if the specifics…

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 imani_dube 19k · 7 months ago
22 votes 2 answers12k views
Has anyone independently verified an SSA survodutide batch COA?

For reference: SSA · survodutide. Somebody stated this to me confidently and I would like to check it before repeating it. I would accept a well-reasoned negative…

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
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…

749 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
asked by u100_marks 38k · 5 months ago
13 votes 5 answers7.3k views
Why would VendorInvestigate report 99.4% where the supplier certificate says something higher?

The specifics, since they change the answer: VendorInvestigate · 99.4%. An unexpected observation, and I would like a differential rather than reassurance. The…

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
hplc
hplc

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

466 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
asked by sample_id 17k · 7 months ago
21 votes 3 answers5.2k views
Can peptide mapping detect a D-amino acid or a scrambled sequence that co-elutes with the main peak?

The recurring point in this tag is that stereoisomers and sequence isomers are invisible to mass spectrometry. I accept that for intact mass. What I want to know is…

peptide-mapping
peptide-mapping

Enzymatic digestion followed by LC-MS/MS to confirm sequence rather than just mass. The method that catches a scrambled sequence or a D-amino-acid…

83 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
lc-ms
lc-ms

Liquid chromatography coupled to mass spectrometry: separation and identification in one run, and the method of choice when you need to know not…

14 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…

749 questions
reference-standard
reference-standard

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

179 questions
asked by Dr_Jonas_Halvorsen 41k · 6 months ago
2 votes 5 answers3.3k views
How do I convert the STEP 3 hazard ratio into an absolute risk reduction?

I have three data points across nine months, which I hope is enough to see a trend. I can do the algebra. I am not confident about the conversion factors. If there is…

cardiovascular
cardiovascular

Cardiovascular outcomes: the SELECT major-adverse-event result, SOUL, SUSTAIN 6 and REWIND, how to convert a hazard ratio into an absolute risk…

111 questions
clinical-trials
clinical-trials

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

913 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…

811 questions
asked by threadlock7 14k · 6 months ago
25 votes3 answers9.4k views
How should I read a sequence of three DEXA scans over nine months of semaglutide?

I have three scans from the same centre, same technician, morning fasted each time, and I want a sanity check on how to read them, because the second scan made me cut…

dexa
dexa

Dual-energy X-ray absorptiometry: what it measures, its precision limits, why hydration state and scan positioning move the numbers, and how to…

84 questions
lean-mass
lean-mass

Lean body mass as measured rather than assumed: what DEXA, BIA and air-displacement plethysmography each actually estimate, the body-composition…

164 questions
resistance-training
resistance-training

Loaded training as the primary intervention for retaining lean mass in a deficit: minimum effective dose, frequency versus volume, and why…

40 questions
protein-intake
protein-intake

Protein targets in grams per kilogram, per-meal distribution and the leucine threshold, and the evidence for a higher intake specifically during…

53 questions
asked by vialroom 87k · 6 months ago
13 votes 5 answers8.3k views
What is the dead-space loss per draw with a 29G needle at 2.5 mg/mL?

For reference: a 29G needle · 2.5 mg/mL. I would like the arithmetic checked rather than the conclusion asserted. I have deliberately not used an online calculator…

dead-space
dead-space

The volume trapped in the syringe hub and needle after the plunger bottoms out. It is small in absolute terms and large as a fraction of a small…

110 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…

268 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…

811 questions
asked by Dr_Otto_Lindqvist 38k · 8 months ago
2 votes0 answers693 views
Would you accept 99.4% on orforglipron from GGPeps without a content assay?

What I have: 99.4% · orforglipron · GGPeps. I would rather over-plan the first cycle and simplify later. I am prepared to do the work if someone can tell me which…

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 nynke_dekker 18k · 3 months ago
17 votes 5 answers7.3k views
What does the mechanism of dulaglutide predict that SURMOUNT-4 did not test?

Stated plainly: dulaglutide · SURMOUNT-4. The empirical answer seems settled. The explanation does not. If the honest answer is that nobody knows, I would rather hear…

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…

175 questions
clinical-trials
clinical-trials

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

913 questions
gip-receptor
gip-receptor

GIP receptor pharmacology, and the still-unsettled question of whether agonism or antagonism at GIPR is the metabolically useful direction.…

83 questions
asked by u100_marks 38k · 6 months ago
16 votes5 answers13k views
Is 98.8% a realistic purity ceiling for cagrilintide given its chain length?

Setup, so nobody has to ask: 98.8% · cagrilintide. I have worked this out and I would like someone to find the error, because I suspect there is one. My working so…

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
hplc
hplc

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

466 questions
peptide-mapping
peptide-mapping

Enzymatic digestion followed by LC-MS/MS to confirm sequence rather than just mass. The method that catches a scrambled sequence or a D-amino-acid…

83 questions
asked by drawn_and_capped 15k · 8 months ago
18 votes 4 answers12k views
What does a 97.6% purity with a list of related substances attached let me conclude?

For reference: 97.6% · list of related substances. I have the document in front of me and I can read the numbers. What I cannot do is interpret them. I am reasonably…

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
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…

749 questions
hplc
hplc

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

466 questions
asked by ellis_thorne 17k · 6 months ago
17 votes0 answers5.6k views
What does a 98.8% purity with a lot-specific certificate attached let me conclude?

Details up front: 98.8% · lot-specific certificate. This is presented as though it settles something, and I am not convinced it does. I have two documents that appear…

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
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…

749 questions
hplc
hplc

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

466 questions
asked by Dr_Malik_Osei 37k · 3 months ago
25 votes 5 answers7k views
How much of the gross mass of a 50 mg semaglutide vial is actually peptide?

The specifics, since they change the answer: 50 mg · semaglutide. I would like the arithmetic checked rather than the conclusion asserted. I have deliberately not…

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
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
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
asked by jo_vandeberg 19k · 7 months ago
17 votes5 answers13k views
What does the mechanism of cagrilintide predict that STEP 1 did not test?

Numbers first: cagrilintide · STEP 1. I suspect the usual explanation for this is wrong, or at least incomplete. I am aware this may have a boring answer. I would…

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…

175 questions
clinical-trials
clinical-trials

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

913 questions
gip-receptor
gip-receptor

GIP receptor pharmacology, and the still-unsettled question of whether agonism or antagonism at GIPR is the metabolically useful direction.…

83 questions
asked by g_paskevicius 44k · 8 months ago