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Unanswered questions

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

741 questions · page 19 of 31

12 votes0 answers11k views
Does holding at 5 mg for eight weeks before escalating reduce headache?

Stated plainly: 5 mg · eight weeks · headache. The empirical answer seems settled. The explanation does not. If the honest answer is that nobody knows, I would rather…

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
nausea
nausea

The dominant tolerability signal in every trial of the class: incidence, timing relative to a dose step, duration, and the distinction between…

346 questions
dose-escalation
dose-escalation

The decision to move up a step: what evidence supports a four-week interval, what happens when you compress it, and how trial protocols handled…

88 questions
asked by tobias_reint 19k · 17 months ago
28 votes0 answers29k views
What is the thermal exposure on a Changsha to Singapore lane in summer?

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

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…

524 questions
international-shipping
international-shipping

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

427 questions
storage
storage

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

646 questions
asked by bea_forsberg 14k · 17 months ago
3 votes0 answers1.5k views
How do I get 15 units out of a vial reconstituted to 4 mg/mL without guessing?

Numbers first: 15 units · 4 mg/mL. I can find plenty of assertions about this and almost no reasoning, which is usually a sign that nobody has checked. Assume no…

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
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 assay_blank 39k · 17 months ago
35 votes0 answers12k views
Is a chromatogram from GL Biochem sufficient basis to skip independent testing?

Concretely: chromatogram · GL Biochem. The failure mode I am trying to avoid is making this decision emotionally. I have twelve months in view and I would like the…

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
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
asked by Dr_Fatima_Belkacem 52k · 17 months ago
3 votes0 answers4.4k views
Is a 29G needle the right choice for drawing semaglutide at 20 mg/mL?

For reference: a 29G needle · semaglutide · 20 mg/mL. The comparison I want does not seem to exist anywhere in a form I can evaluate. I have read the arguments for…

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…

85 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…

90 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…

110 questions
asked by jo_vandeberg 19k · 17 months ago
25 votes0 answers13k views
Would you accept 99.4% on cagrilintide from TFC without a content assay?

What I am working with: 99.4% · cagrilintide · TFC. I would like to set this up properly once, rather than adjust it repeatedly. My budget is real but not tight, and…

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 two_two_micron 15k · 17 months ago
19 votes0 answers8.2k views
Is there any published stability data for dulaglutide at 4 °C?

Stated plainly: dulaglutide · 4 °C. This is asserted often enough that I assumed it was established, and then I went looking for the source. I have searched the…

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
clinical-trials
clinical-trials

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

913 questions
asked by Dr_Fatima_Belkacem 52k · 17 months ago
26 votes0 answers22k views
What is the real-world lead time from Tianjin to New Zealand in winter?

For reference: Tianjin · New Zealand. I have the document in front of me and I can read the numbers. What I cannot do is interpret them. I am reasonably comfortable…

international-shipping
international-shipping

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

427 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…

524 questions
customs
customs

Customs handling: how declarations are assessed, why a parcel sits at a facility for a week, seizure notices, and the practical difference between…

186 questions
asked by two_two_micron 15k · 17 months ago
19 votes0 answers13k views
How is a beyond-use date set for compounded dulaglutide in phosphate-buffered diluent?

Setup, so nobody has to ask: dulaglutide · phosphate-buffered diluent. This is a procedural question rather than a theoretical one, and I would like the procedure…

compounding
compounding

Compounded preparations: what a 503A and a 503B facility may legally prepare and when, base versus salt forms, beyond-use dating under USP…

61 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…

301 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;…

112 questions
asked by fill_volume 13k · 17 months ago
30 votes0 answers31k views
Is potassium worth drawing at baseline before starting survodutide?

The specifics, since they change the answer: potassium · survodutide. I am at the decision point and I would rather think it through than improvise. I would rather…

bloodwork
bloodwork

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

284 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
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…

108 questions
asked by n_takahashi 36k · 17 months ago
13 votes0 answers6.4k views
How comparable are mazdutide and semaglutide on the evidence available?

Numbers first: mazdutide · semaglutide. I want to know what the trade-off actually is rather than which option is fashionable. I would rather have a defensible reason…

clinical-trials
clinical-trials

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

913 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
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…

162 questions
asked by second_lot 11k · 17 months ago
11 votes0 answers4.9k views
Has anyone independently verified an SGN dulaglutide batch COA?

What I have: SGN · dulaglutide. I am asking for verification rather than opinion, ideally with something I can read myself. It is possible the evidence exists and I…

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 linnea_wahlberg 14k · 17 months ago
38 votes0 answers29k views
What does SURMOUNT-OSA tell me about hair thinning at the 30 mg dose?

For reference: SURMOUNT-OSA · hair thinning · 30 mg. I want to understand what this actually establishes, as opposed to what it is being used to imply. My concern is…

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 petra_hovland 42k · 17 months ago
24 votes0 answers17k views
How do I reconcile 98.4% from Janoshik with 98.2% from the supplier?

Numbers first: 98.4% · Janoshik · 98.2%. Before I write this off, I want to check whether it is a known failure mode. I have the lot number, the certificate and 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
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
asked by rae_oyelowo 21k · 17 months ago
27 votes0 answers8.4k views
What is the most common avoidable mistake in reconstitution?

This is the third vial from the same lot, so I can compare against two known-good ones. I suspect the usual explanation for this is wrong, or at least incomplete. 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,…

330 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
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
asked by otto_brenner 19k · 17 months ago
34 votes0 answers25k views
Mazdutide compared to survodutide on published data?

My background is chemistry rather than physiology, which may explain where I am stuck. These are treated as interchangeable and I do not think they are. If both are…

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.…

14 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…

14 questions
clinical-trials
clinical-trials

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

913 questions
asked by eighty_six_hours 16k · 17 months ago
37 votes0 answers34k views
Is 98.4% a realistic purity ceiling for ecnoglutide given its chain length?

For reference: 98.4% · ecnoglutide. I would like the arithmetic checked rather than the conclusion asserted. I have deliberately not used an online calculator because…

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 pk_curve 12k · 17 months ago
32 votes0 answers25k views
How many units on a U-40 insulin syringe is a 8 mg dose at 6.67 mg/mL?

Concretely: a U-40 insulin syringe · 8 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…

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 net_peptide 16k · 18 months ago
32 votes0 answers23k views
Is a 99.4% result from Medutest comparable to 96.4% from PeptideMeter?

Stated plainly: 99.4% · Medutest · 96.4% · PeptideMeter. Both of these get recommended confidently by different people, which suggests neither is obviously right. My…

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
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
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 anouk_desmet 18k · 18 months ago
33 votes0 answers27k views
How does WWB compare to WuXi TIDES on documentation quality?

What I have: 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,…

351 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 charge_state_3 39k · 18 months ago
9 votes0 answers4.8k views
How do I compute the +2 charge state m/z for a peptide of 4731.3 Da?

Details up front: +2 · 4731.3 Da. This should be a straightforward calculation and I keep getting two different answers. The numbers are arbitrary; the method is what…

mass-spec
mass-spec

Mass spectrometry for identity confirmation: electrospray ionisation, multiple charge states, monoisotopic versus average mass, deconvolution, and…

38 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
purity
purity

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

788 questions
asked by kofi_mensah 12k · 18 months ago
21 votes0 answers24k views
Can I reconstitute dulaglutide at 20 mg/mL and still measure a small dose accurately?

What I am working with: dulaglutide · 20 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…

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 klara_novotna 16k · 18 months ago
15 votes0 answers17k views
Is benzyl alcohol at 0.9% enough to matter for peptide stability?

My setup is a refrigerator with a logger and a small work area I wipe down, nothing more. This is one of those things that everyone repeats and nobody derives. This…

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;…

112 questions
peptide-stability
peptide-stability

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

832 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…

301 questions
asked by dana_wexler 15k · 18 months ago
12 votes0 answers4.6k views
What should a twenty-person split record so a bank transfer dispute can be settled?

Concretely: a twenty-person split · a bank transfer. I am trying to do this correctly the first time rather than learn it by getting it wrong. I have already made one…

group-buy
group-buy

Pooled purchasing: how the economics work, what trust structure a pool needs, splitting a single tested lot, and the failure modes when the…

41 questions
payment-privacy
payment-privacy

Payment mechanics and their privacy properties: why suppliers ask for stablecoin transfers, what an on-chain transfer reveals, confirmation…

31 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
asked by esben_lykke 15k · 18 months ago