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Unanswered questions

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

741 questions · page 8 of 31

15 votes0 answers7.1k views
Is QYB worth the price difference against Hubei Jianxiang Bioscience on measured results?

For reference: QYB · Hubei Jianxiang Bioscience. I am trying to choose between two options that are usually discussed as though only one exists. I am not optimising…

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
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
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 claudia_ferrante 46k · 7 months ago
18 votes0 answers9.8k views
How does cagrilintide at 2.5 mg weekly compare on cost per milligram across routes?

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

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
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
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 rania_haddad 17k · 7 months ago
13 votes0 answers6k views
How does oral semaglutide at 60 mg weekly compare on cost per milligram across routes?

The specifics, since they change the answer: oral semaglutide · 60 mg. I would like the arithmetic checked rather than the conclusion asserted. I have deliberately…

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
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
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 · 7 months ago
17 votes0 answers4k views
Has anyone independently verified a BCH a GLP-1 receptor agonist batch COA?

What I am working with: BCH · a GLP-1 receptor agonist. This has the shape of a fact but I cannot find its origin. What I found instead were three secondary sources…

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 nils_karlberg 13k · 7 months ago
24 votes0 answers8.9k views
Is mazdutide at 2.5 mg/mL stable enough for two weeks of multi-withdrawal use?

Numbers first: mazdutide · 2.5 mg/mL · two weeks. I am asking for verification rather than opinion, ideally with something I can read myself. It is possible the…

peptide-stability
peptide-stability

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

832 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
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 t_oyelaran 41k · 7 months ago
12 votes0 answers2.8k views
Is 4 mg/mL a sensible working concentration for oral semaglutide, or should I go lower?

The case in front of me: 4 mg/mL · oral semaglutide. I would like the axes of comparison first and the recommendation second. I have tried the first option and it…

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
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
asked by birk_nordahl 20k · 7 months ago
19 votes0 answers9.3k views
What should be in place before a first semaglutide vial arrives from Tianjin?

The case in front of me: semaglutide · Tianjin. The failure mode I am trying to avoid is making this decision emotionally. I have twelve months in view and I would…

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
research-use-only
research-use-only

What "for research use only" means as a legal and practical designation: not approved for human use, no pharmacopoeial release testing, no…

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…

122 questions
asked by mg_per_ml 12k · 7 months ago
24 votes0 answers10k views
Is 8 mg/mL a sensible working concentration for ecnoglutide, or should I go lower?

The specifics, since they change the answer: 8 mg/mL · ecnoglutide. The comparison I want does not seem to exist anywhere in a form I can evaluate. I have read the…

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
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
asked by otto_brenner 19k · 7 months ago
22 votes0 answers7.3k views
What counter-ion should I expect on a GGPeps semaglutide lot?

The specifics, since they change the answer: GGPeps · semaglutide. I want to understand what this actually establishes, as opposed to what it is being used to imply.…

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 Dr_Elias_Weiss 46k · 7 months ago
9 votes0 answers4.6k views
If I reconstitute a 20 mg vial with 1.5 mL of bacteriostatic water, what concentration do I end up with?

What I am working with: 20 mg · 1.5 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,…

330 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
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 priya_menon 11k · 7 months ago
5 votes0 answers1.2k views
Is a batch certificate the same claim as a vial certificate?

I am comparing a supplier certificate against an independent result on the same lot. Both of these get recommended confidently by different people, which suggests…

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 unit_math 13k · 7 months ago
22 votes0 answers12k views
What fraction of loss on retatrutide is lean mass according to STEP 1?

What I am working with: retatrutide · STEP 1. I would like help reading this properly rather than being told what conclusion to reach. I have the full report…

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
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…

82 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…

84 questions
asked by kelvin_lam 11k · 7 months ago
17 votes0 answers4.4k views
Is 2.5 mg in 2.5 mL of 0.9% sodium chloride a sensible presentation for a GLP-1 receptor agonist?

Conditions: 2.5 mg · 2.5 mL · 0.9% sodium chloride · a GLP-1 receptor agonist. I want to decide this in advance so that I am not deciding it under pressure later.…

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
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
asked by greta_holzmann 15k · 7 months ago
18 votes0 answers7.7k views
How does QYB compare to Qingdao Saber Technology on documentation quality?

For reference: QYB · Qingdao Saber Technology. I am trying to choose between two options that are usually discussed as though only one exists. I am not optimising for…

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 wren_calloway 14k · 7 months ago
16 votes0 answers3.4k views
How many weeks to steady state for dulaglutide on a weekly schedule?

This matters because it predicts what a related molecule should do. The units are where I keep going wrong, so please be explicit about them. I have sanity-checked…

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
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
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 h_villanueva 50k · 7 months ago
4 votes0 answers2.6k views
How does HJ compare to Wuhan Wansheng Biotechnology on documentation quality?

The case in front of me: HJ · Wuhan Wansheng Biotechnology. I would like the axes of comparison first and the recommendation second. I have tried the first option and…

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 leah_ferrers 15k · 7 months ago
10 votes0 answers5.9k views
What is the arithmetic to convert 15 mg in 0.5 mL into units on a U-100 scale?

The particulars: 15 mg · 0.5 mL. I would rather understand the derivation than memorise the outcome. Two people I asked gave two answers that differ by a factor of…

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 pip_okonjo 11k · 7 months ago
10 votes0 answers5.2k views
How do I compare MKM and HJ on lead time to Canada?

The specifics, since they change the answer: MKM · HJ · Canada. The comparison I want does not seem to exist anywhere in a form I can evaluate. I have read the…

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
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
asked by cap_the_luer 15k · 7 months ago
9 votes0 answers3.4k views
Does oxidation dominate for oral semaglutide held at 2–8 °C?

The case in front of me: oxidation · oral semaglutide · 2–8 °C. This is one of those things that everyone repeats and nobody derives. This matters practically, not…

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 forty_units 14k · 7 months ago
2 votes0 answers791 views
Does tirzepatide adsorb measurably to the vial wall at 1 mg/mL?

The specifics, since they change the answer: tirzepatide · 1 mg/mL. I would like the arithmetic checked rather than the conclusion asserted. I have deliberately not…

peptide-stability
peptide-stability

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

832 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
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 gunnar_isaksen 16k · 7 months ago
5 votes0 answers1.9k views
How many vials from an MKM lot should I send for an endotoxin test?

The specifics, since they change the answer: MKM · an endotoxin test. I would like the arithmetic checked rather than the conclusion asserted. I have deliberately not…

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 two_two_micron 15k · 7 months ago
17 votes0 answers7.4k views
What does the mechanism of dulaglutide predict that SURMOUNT-1 did not test?

What I am working with: dulaglutide · SURMOUNT-1. The empirical answer seems settled. The explanation does not. If the honest answer is that nobody knows, 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 tobias_maartens 94k · 7 months ago
18 votes0 answers7.7k views
What is the dead-space loss per draw with a 18G drawing needle at 4 mg/mL?

Numbers first: an 18G drawing needle · 4 mg/mL. This should be a straightforward calculation and I keep getting two different answers. The numbers are arbitrary; the…

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 marta_szymanska 17k · 7 months ago
24 votes0 answers14k views
Is a WXT order from Zhuhai likely to hold cold chain to South Africa?

Setup, so nobody has to ask: WXT · Zhuhai · South Africa. I would like to set this up properly once, rather than adjust it repeatedly. My budget is real but not…

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
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
asked by lucia_marchetti 18k · 8 months ago