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1.4k questions · page 26 of 60

33 votes 5 answers35k views
Is a 25G drawing needle the right choice for drawing cagrilintide at 10 mg/mL?

What I am working with: a 25G drawing needle · cagrilintide · 10 mg/mL. I suspect the honest answer is that it depends, in which case I would like to know on what.…

needle-gauge
needle-gauge

Gauge and length selection, the trade-off between draw time and tissue trauma, coring risk with larger-bore needles, and why a fixed-needle…

91 questions
injection-technique
injection-technique

Technique questions: angle, pinch versus flat, aspiration, injection speed, air bubbles, and the handling steps that determine whether you deliver…

96 questions
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…

117 questions
amylin
amylin

Amylin and its analogues, most prominently cagrilintide, as a satiety mechanism orthogonal to incretin signalling. Includes the pharmacology of…

237 questions
asked by grainne_ahearn 50k · 13 months ago
33 votes5 answers34k views
How do I convert the PIONEER-1 hazard ratio into an absolute risk reduction?

My laboratory results are from the same laboratory each time, drawn fasting, which I gather matters. Please show the division. I want to check my own against yours. I…

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…

68 questions
clinical-trials
clinical-trials

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

745 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 sunniva_dahl 22k · 16 months ago
33 votes0 answers34k views
Does the SURPASS-3 population resemble anyone asking about tirzepatide here?

What I have: SURPASS-3 · tirzepatide. I can parse the result. I am less sure what it licenses me to conclude. I have deliberately not looked at anyone else’s…

clinical-trials
clinical-trials

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

745 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
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 birk_nordahl 16k · 18 months ago
33 votes 5 answers34k views
What is the thermal exposure on a Nantong to Canada lane in summer?

The specifics, since they change the answer: Nantong · Canada. I have read the primary source rather than the summary, which has left me with more questions. I…

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 tamsin_wray 9.9k · 12 months ago
33 votes0 answers33k views
Why do two papers on PIONEER-1 report different headline figures?

My laboratory results are from the same laboratory each time, drawn fasting, which I gather matters. I want to know whether this is a real physical effect or an…

clinical-trials
clinical-trials

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

745 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
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 noor_alhassan 11k · 19 months ago
33 votes 5 answers32k views
Why would VendorInvestigate report 95.2% where the supplier certificate says something higher?

The specifics, since they change the answer: VendorInvestigate · 95.2%. Something has gone wrong and I would like to know how badly before I decide what to do.…

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
hplc
hplc

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

503 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
vendor-investigate
vendor-investigate

VendorInvestigate, an independent vendor review and verification service. Use this tag for questions about its verification criteria, what a…

113 questions
asked by nils_karlberg 9.4k · 12 months ago
33 votes5 answers32k views
Is a mini-fridge good enough for storing reconstituted cagrilintide?

The specifics, since they change the answer: a mini-fridge · cagrilintide. I would like to set this up properly once, rather than adjust it repeatedly. My budget is…

storage
storage

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

701 questions
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
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
amylin
amylin

Amylin and its analogues, most prominently cagrilintide, as a satiety mechanism orthogonal to incretin signalling. Includes the pharmacology of…

237 questions
asked by aine_mulcahy 28k · 14 months ago
33 votes 5 answers31k views
How would I detect oxidation in a tirzepatide vial without sending it to Janoshik?

The case in front of me: oxidation · tirzepatide · Janoshik. I have done this once and I suspect I got away with it rather than got it right. For context: I keep…

vial-inspection
vial-inspection

What you can learn by looking: cake morphology, meniscus films, fibres versus stopper fragments versus true particulates, clarity after…

66 questions
peptide-stability
peptide-stability

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

908 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
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
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 bac_or_bust 33k · 13 months ago
33 votes 5 answers30k views
Does constipation at week six of orforglipron usually resolve without a dose change?

For reference: constipation · six · orforglipron. I have done this once and I suspect I got away with it rather than got it right. For context: I keep records of…

constipation
constipation

Slowed transit as a consequence of delayed gastric emptying and reduced intake: incidence figures, fibre and hydration evidence, and why it often…

55 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 Dr_Signe_Baldursdottir 29k · 19 months ago
33 votes5 answers29k views
Does a DEXA repeated every three weeks give me a usable lean-mass trend?

I would like to know what to measure as much as what to do. Both of these get recommended confidently by different people, which suggests neither is obviously right.…

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…

39 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…

127 questions
muscle-loss
muscle-loss

Loss of contractile tissue during energy deficit: what fraction of total loss is lean mass, why the commonly quoted figures are measurement…

39 questions
asked by hana_petrikova 10k · 12 months ago
33 votes 5 answers29k views
Is 5 mg in 2.5 mL of bacteriostatic water a sensible presentation for oral semaglutide?

Setup, so nobody has to ask: 5 mg · 2.5 mL · bacteriostatic water · oral semaglutide. I would like to set this up properly once, rather than adjust it repeatedly. My…

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
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
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
bacteriostatic-water
bacteriostatic-water

Water for injection containing roughly 0.9 per cent benzyl alcohol as a bacteriostatic agent. It suppresses growth in a multiple-withdrawal vial;…

149 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 mateo_iglesias 12k · 15 months ago
33 votes5 answers28k views
Is a GL Biochem order from Guangzhou likely to hold cold chain to Canada?

Conditions: GL Biochem · Guangzhou · Canada. I would like to define my thresholds before I have a result, for obvious reasons. I want a plan with explicit stopping…

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
vendor-comparison
vendor-comparison

Side-by-side comparison of suppliers on measurable axes - independently confirmed purity and content, lead time, cold-chain handling,…

388 questions
asked by nils_karlberg 9.4k · 16 months ago
33 votes 5 answers27k views
Would you accept 99.4% on dulaglutide from QYB without a content assay?

Details up front: 99.4% · dulaglutide · QYB. 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…

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
dulaglutide
dulaglutide

A once-weekly GLP-1 receptor agonist built on an Fc fusion rather than fatty-acid acylation. Use this tag for questions about the fusion-protein…

200 questions
asked by marta_okonkwo 190k · 18 months ago
33 votes 5 answers27k views
How does FGP compare to Nantong Guangyuan Chemical on documentation quality?

What I have: FGP · Nantong Guangyuan Chemical. Both of these get recommended confidently by different people, which suggests neither is obviously right. My…

vendor-comparison
vendor-comparison

Side-by-side comparison of suppliers on measurable axes - independently confirmed purity and content, lead time, cold-chain handling,…

388 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
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
asked by rhian_prydderch 23k · 19 months ago
33 votes0 answers27k views
How does WWB compare to WuXi TIDES on documentation quality?

Conditions: WWB · WuXi TIDES. I want to know what the trade-off actually is rather than which option is fashionable. I would rather have a defensible reason than a…

vendor-comparison
vendor-comparison

Side-by-side comparison of suppliers on measurable axes - independently confirmed purity and content, lead time, cold-chain handling,…

388 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
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
asked by charge_state_3 16k · 18 months ago
33 votes5 answers25k views
How would I detect deamidation in a semaglutide vial without sending it to Medutest?

The particulars: deamidation · semaglutide · Medutest. I have read the obvious sources and they disagree with each other, so I would rather ask people who have…

vial-inspection
vial-inspection

What you can learn by looking: cake morphology, meniscus films, fibres versus stopper fragments versus true particulates, clarity after…

66 questions
peptide-stability
peptide-stability

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

908 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
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
medutest
medutest

Medutest, one of four independent testing and verification services referenced throughout this site. Use this tag for its methods, its report…

126 questions
asked by petra_hovland 35k · 17 months ago
33 votes 5 answers25k views
What fraction of loss on oral semaglutide is lean mass according to SOUL?

Stated plainly: oral semaglutide · SOUL. The figures are clear enough; the question is what they mean and what they do not. I can supply the numbers if the specifics…

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…

127 questions
muscle-loss
muscle-loss

Loss of contractile tissue during energy deficit: what fraction of total loss is lean mass, why the commonly quoted figures are measurement…

39 questions
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…

39 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 ravenna_pace 14k · 15 months ago
33 votes0 answers25k views
Why do two papers on SURMOUNT-OSA report different headline figures?

This is a question about interpretation, not about whether to act — I will take action questions elsewhere. I keep seeing this stated as a fact with no explanation…

clinical-trials
clinical-trials

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

745 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
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 juan_esquivel 14k · 19 months ago
33 votes 5 answers25k views
What happens to orforglipron after eight weeks at 30 °C in solution?

Stated plainly: orforglipron · eight weeks · 30 °C. I keep seeing this stated as a fact with no explanation attached, and unexplained facts make me suspicious. My…

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
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 Dr_Aoife_Brennan 20k · 20 months ago
33 votes5 answers24k views
How many units on a low-dead-space syringe is an 8 mg dose at 8 mg/mL?

Conditions: a low-dead-space syringe · 8 mg · 8 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 pierce_count 24k · 13 months ago
33 votes5 answers24k views
What would you ask Zhuhai Kerui Biotechnology before a first order that they cannot fake?

I have certificates from two lots and an independent result on one of them. I can find plenty of assertions about this and almost no reasoning, which is usually a…

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
asked by v_ramaswamy 68k · 18 months ago
33 votes5 answers24k views
What does a 97.6% purity with a date of analysis attached let me conclude?

Conditions: 97.6% · date of analysis. I would like to know the limits of what can be inferred from this. What I am trying to avoid is over-reading a single result,…

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
asked by juan_esquivel 14k · 14 months ago
33 votes 5 answers24k views
What does TRIUMPH-3 tell me about constipation at the 4 mg dose?

Details up front: TRIUMPH-3 · constipation · 4 mg. This is presented as though it settles something, and I am not convinced it does. I have two documents that appear…

clinical-trials
clinical-trials

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

745 questions
constipation
constipation

Slowed transit as a consequence of delayed gastric emptying and reduced intake: incidence figures, fibre and hydration evidence, and why it often…

55 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 forty_units 16k · 12 months ago
33 votes 5 answers23k views
How many freeze-thaw cycles will mazdutide at 10 mg/mL tolerate?

What I have: mazdutide · 10 mg/mL. I would like to understand the steps well enough to explain them to someone else. I have access to a refrigerator with a logger and…

freeze-thaw
freeze-thaw

What repeated freezing does to a peptide in solution: ice-crystal shear at the growing front, freeze-concentration of solutes, pH shifts as buffer…

57 questions
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
mazdutide
mazdutide

A GLP-1 and glucagon receptor dual agonist developed primarily in China, with a distinct dose range and a fast-moving publication record.…

237 questions
asked by tamsin_wray 9.9k · 13 months ago