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Newest first. 5.2k questions across 107 tags.

5.2k questions · page 195 of 217

39 votes 2 answers62k views
Does splitting a 5 mg weekly dose of survodutide across two administrations change anything?

The particulars: 5 mg · survodutide. I would like the mechanism, because I want to be able to reason about the cases nobody has written about. I have tried to reason…

split-dosing
split-dosing

Dividing a weekly dose across more than one administration. Questions here concern the pharmacokinetic rationale, whether the peak-to-trough ratio…

44 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
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
survodutide
survodutide

A GLP-1 and glucagon receptor dual agonist with a substantial published MASH dataset. Use this tag for its hepatic endpoints, its dose ladder, and…

225 questions
asked by Dr_Malik_Osei 19k · 2.1 years ago
32 votes 5 answers67k views
Has anyone independently verified a QYB survodutide batch COA?

Details up front: QYB · 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…

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
survodutide
survodutide

A GLP-1 and glucagon receptor dual agonist with a substantial published MASH dataset. Use this tag for its hepatic endpoints, its dose ladder, and…

225 questions
asked by gunnar_isaksen 14k · 2.1 years ago
6 votes 5 answers18k views
How many times can I pierce a stopper with an 18G drawing needle before coring?

I keep a written log of every draw with date, volume and syringe type. I want a method I can write down and repeat, not a rule of thumb. I would rather over-engineer…

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
sterility
sterility

Sterility as a test result rather than an adjective. Covers what a sterility test actually measures, why "sterile filtered" on a document is close…

142 questions
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
asked by j_wierzbicki 69k · 2.1 years ago
28 votes0 answers15k views
How do I interpret a cystatin C trend across three draws?

I have three data points across nine months, which I hope is enough to see a trend. I want to understand what this actually establishes, as opposed to what it is…

bloodwork
bloodwork

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

296 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
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
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
asked by nominal_ten 12k · 2.1 years ago
39 votes 5 answers50k views
Is a wine cooler good enough for storing reconstituted survodutide?

The specifics, since they change the answer: a wine cooler · survodutide. I would like to define my thresholds before I have a result, for obvious reasons. I want a…

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
survodutide
survodutide

A GLP-1 and glucagon receptor dual agonist with a substantial published MASH dataset. Use this tag for its hepatic endpoints, its dose ladder, and…

225 questions
asked by mira_sundqvist 7.1k · 2.1 years ago
9 votes 4 answers27k views
What does SURMOUNT-OSA actually establish about tirzepatide?

What I have: SURMOUNT-OSA · tirzepatide. I want to understand what this actually establishes, as opposed to what it is being used to imply. My concern is that I am…

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
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
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 fib4_reader 24k · 2.1 years ago
36 votes5 answers57k views
Is a 30G needle the right choice for drawing cagrilintide at 10 mg/mL?

Stated plainly: a 30G needle · cagrilintide · 10 mg/mL. Both of these get recommended confidently by different people, which suggests neither is obviously right. My…

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 esther_vandeVelde 52k · 2.1 years ago
27 votes 5 answers35k views
How long does dulaglutide stay within specification at 37 °C once reconstituted?

What I am working with: dulaglutide · 37 °C. This is a procedural question rather than a theoretical one, and I would like the procedure rather than the theory. What…

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
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 forty_two_c 66k · 2.1 years ago
13 votes 5 answers33k views
If I reconstitute a 5 mg vial with 2.5 mL of bacteriostatic water, what concentration do I end up with?

What I am working with: 5 mg · 2.5 mL · bacteriostatic water. I have worked this out and I would like someone to find the error, because I suspect there is one. My…

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
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
asked by nynke_dekker 9.4k · 2.1 years ago
35 votes5 answers59k views
My cagrilintide vial sat at 2–8 °C for twenty-eight days — is testing worth it before use?

Numbers first: cagrilintide · 2–8 °C · twenty-eight days. I would rather over-plan the first cycle and simplify later. I am prepared to do the work if someone can…

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
peptide-stability
peptide-stability

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

908 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
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 lukas_sedlacek 16k · 2.1 years ago
12 votes 5 answers11k views
How comparable are a GLP-1 receptor agonist and tirzepatide on the evidence available?

Numbers first: a GLP-1 receptor agonist · tirzepatide. I have used one of these for a while and I am considering switching, which requires a reason. What I care about…

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 rune_thoresen 16k · 2.1 years ago
26 votes0 answers25k views
What does an HPLC purity test add for orforglipron that a purity figure does not?

Setup, so nobody has to ask: an HPLC purity test · orforglipron. I have used one of these for a while and I am considering switching, which requires a reason. What 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
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
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 ekaterina_volk 21k · 2.1 years ago
9 votes0 answers5.7k views
Is 12 mg weekly a defensible maintenance dose for orforglipron?

Numbers first: 12 mg · orforglipron. 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…

maintenance-dose
maintenance-dose

Staying put: the lowest dose that holds a result, the difference between the maximum studied dose and the maximum useful dose, and what the…

54 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
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 tyndall_haze 38k · 2.1 years ago
14 votes 5 answers40k views
How many vial-days does an 8 mg vial give at 10 mg/mL on a weekly schedule?

Numbers first: 8 mg · 10 mg/mL. I can do the algebra. I am not confident about the conversion factors. If there is a standard way to lay this out, I would rather…

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
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
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
asked by mg_per_ml 15k · 2.1 years ago
4 votes0 answers2.5k views
Does reflux at week three of tirzepatide usually resolve without a dose change?

The particulars: reflux · three · tirzepatide. I would like to understand the steps well enough to explain them to someone else. I have access to a refrigerator with…

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
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
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 mass_shift_18 9.7k · 2.1 years ago
17 votes5 answers42k views
What is the thermal exposure on a Qingdao to Ireland lane in summer?

For reference: Qingdao · Ireland. This is presented as though it settles something, and I am not convinced it does. I have two documents that appear to disagree,…

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 teodora_ilic 17k · 2.1 years ago
34 votes3 answers17k views
What are the rodent C-cell findings behind the thyroid warning, and do they transfer to humans?

The US labelling for several drugs in this class carries a boxed warning about thyroid C-cell tumours, and it is stated fairly starkly — tumours in both rats and…

thyroid
thyroid

Thyroid questions: the rodent C-cell findings behind the labelled warning, human calcitonin data, TSH drift during weight loss, and the…

23 questions
clinical-trials
clinical-trials

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

745 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
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 swab_and_wait 13k · 2.1 years ago
38 votes0 answers29k views
Is a 97.9% result from VendorInvestigate comparable to 99.4% from Medutest?

Concretely: 97.9% · VendorInvestigate · 99.4% · Medutest. These are treated as interchangeable and I do not think they are. If both are acceptable I would like to…

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
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
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 nine_point_nine 60k · 2.1 years ago
29 votes 5 answers57k views
What does STEP 2 tell me about injection-site erythema at the 2 mg dose?

The case in front of me: STEP 2 · injection-site erythema · 2 mg. The figures are clear enough; the question is what they mean and what they do not. I can supply the…

clinical-trials
clinical-trials

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

745 questions
injection-site-reaction
injection-site-reaction

Local reactions: erythema, induration, pruritus and nodules. Their relationship to injection depth, diluent composition, benzyl alcohol…

49 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 tare_and_weigh 12k · 2.1 years ago
25 votes 5 answers18k views
Is a QST order from Zhuhai likely to hold cold chain to Singapore?

The case in front of me: QST · Zhuhai · Singapore. I want to decide this in advance so that I am not deciding it under pressure later. Assume I will follow the plan 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
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 seamus_brady 15k · 2.1 years ago
38 votes0 answers54k views
Is semaglutide at 8 mg/mL stable enough for three weeks of multi-withdrawal use?

Conditions: semaglutide · 8 mg/mL · three weeks. I want to know whether there is evidence behind this or only repetition. I have checked the obvious registries and…

peptide-stability
peptide-stability

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

908 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
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
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 ravenna_pace 14k · 2.1 years ago
36 votes 5 answers56k views
Does oxidation dominate for liraglutide held at 30 °C?

Conditions: oxidation · liraglutide · 30 °C. This is one of those things that everyone repeats and nobody derives. This matters practically, not just academically,…

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
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 mira_sundqvist 7.1k · 2.1 years ago
25 votes 5 answers52k views
How long does survodutide stay within specification at 2–8 °C once reconstituted?

The case in front of me: survodutide · 2–8 °C. I am trying to do this correctly the first time rather than learn it by getting it wrong. I have already made one…

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
survodutide
survodutide

A GLP-1 and glucagon receptor dual agonist with a substantial published MASH dataset. Use this tag for its hepatic endpoints, its dose ladder, and…

225 questions
asked by nils_karlberg 9.4k · 2.1 years ago
27 votes 5 answers40k views
Is an HJ order from Qingdao likely to hold cold chain to Singapore?

The case in front of me: HJ · Qingdao · Singapore. I want to decide this in advance so that I am not deciding it under pressure later. Assume I will follow the plan 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
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 lukas_sedlacek 16k · 2.1 years ago