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1.4k questions · page 10 of 60

15 votes 4 answers4.5k views
What happens to survodutide after four weeks at 4 °C in solution?

Concretely: survodutide · four weeks · 4 °C. I want to know whether this is a real physical effect or an artefact of how it is measured. What prompted the question is…

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 ravi_pillai 12k · 4 months ago
11 votes 5 answers6k views
How do Medutest and Janoshik compare on the same oral semaglutide batch?

Concretely: Medutest · Janoshik · oral semaglutide. I want to know what the trade-off actually is rather than which option is fashionable. I would rather have a…

janoshik
janoshik

Janoshik Analytical, an independent third-party testing laboratory widely used by this community for HPLC purity, identity and quantified content…

139 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
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
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 ines_delacruz 16k · 2 months ago
14 votes 5 answers4.2k views
How do I convert the PIONEER-4 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 syringe_ninety 12k · 3 months ago
6 votes 5 answers4.7k views
How do I trace a TFC lot number back to a synthesis date?

The method section is present, which is unusual enough that I want to make use of it. I am trying to do this correctly the first time rather than learn it by getting…

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
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 loss_on_drying 40k · 32 days ago
8 votes5 answers6.5k views
Is there a pharmacokinetic case for moving liraglutide injection day by forty-two days?

Conditions: liraglutide · forty-two days. I would like the mechanism, because I want to be able to reason about the cases nobody has written about. I have tried to…

missed-dose
missed-dose

What the label instructions for a missed weekly dose are, why they differ between agents, and what the pharmacokinetics say about drift in an…

41 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
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
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 orla_ferriter 89k · 1 months ago
9 votes 5 answers2.4k views
How do I compare SSA and HJ on lead time to Canada?

For reference: SSA · HJ · Canada. The comparison I want does not seem to exist anywhere in a form I can evaluate. I have read the arguments for each and they do not…

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
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
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
asked by priya_menon 13k · 13 days ago
16 votes5 answers8.2k views
What happens to ecnoglutide after four weeks at 37 °C in solution?

Concretely: ecnoglutide · four weeks · 37 °C. I want to know whether this is a real physical effect or an artefact of how it is measured. What prompted the question…

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
ecnoglutide
ecnoglutide

A long-acting GLP-1 receptor agonist with a cAMP-biased signalling profile. A niche tag, mostly used for mechanism questions about biased agonism…

223 questions
asked by p_mkhize 58k · 3 months ago
11 votes 5 answers2.5k views
What is the arithmetic to convert 10 mg in 1.5 mL into units on a U-100 scale?

The case in front of me: 10 mg · 1.5 mL. Please show the division. I want to check my own against yours. I would like the general form as well as the specific number,…

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 gradient_slope 46k · 44 days ago
19 votes3 answers5k views
How reliably does a Phase 2 dose-ranging result predict the Phase 3 number?

The obesity pipeline is currently full of phase 2 results being quoted as though they were established magnitudes. Retatrutide at -24.2% over 48 weeks is the…

clinical-trials
clinical-trials

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

745 questions
retatrutide
retatrutide

An investigational GLP-1, GIP and glucagon receptor tri-agonist, studied in the TRIUMPH programme. Not approved anywhere. Use this tag for…

251 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
ecnoglutide
ecnoglutide

A long-acting GLP-1 receptor agonist with a cAMP-biased signalling profile. A niche tag, mostly used for mechanism questions about biased agonism…

223 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 ilaria_bertone 33k · 3 months ago
15 votes5 answers6.7k views
Is 6.67 mg/mL a sensible working concentration for oral semaglutide, or should I go lower?

The case in front of me: 6.67 mg/mL · oral semaglutide. These are treated as interchangeable and I do not think they are. If both are acceptable I would like to know…

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
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 kelvin_lam 7.6k · 40 days ago
2 votes5 answers2.8k views
Is resistance training ten times a week enough at 800 kcal a day?

The particulars: ten · 800 kcal. I am at the decision point and I would rather think it through than improvise. I would rather spend money on measurement than on…

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…

43 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
exercise
exercise

Training during substantial weight loss: cardiorespiratory work, step count, low energy availability, and how exercise interacts with the appetite…

38 questions
asked by rune_thoresen 16k · 17 days ago
8 votes 5 answers4.8k views
Does holding at 0.25 mg for two weeks before escalating reduce nausea?

Setup, so nobody has to ask: 0.25 mg · two weeks · nausea. I keep seeing this stated as a fact with no explanation attached, and unexplained facts make me suspicious.…

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
nausea
nausea

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

55 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…

103 questions
asked by marcus_thorbjorn 9.4k · 4 months ago
3 votes 5 answers2.6k views
How do I check that two WXT lots of a GLP-1 receptor agonist agree on content assay?

Stated plainly: WXT · a GLP-1 receptor agonist. I noticed this today and I have not touched anything since, in case the state is diagnostic. I have not discarded…

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
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
asked by plunger_stop 13k · 42 days ago
13 votes 1 answer3.6k views
How much of the gross mass of a 50 mg survodutide vial is actually peptide?

The particulars: 50 mg · survodutide. I would rather understand the derivation than memorise the outcome. Two people I asked gave two answers that differ by a factor…

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
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…

51 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…

88 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 dermot_kiely 12k · 1 months ago
20 votes5 answers7k views
How much protein in grams do I need at 900 kcal a day?

Scale weight, waist circumference and a repetition maximum, all logged weekly. I have worked this out and I would like someone to find the error, because I suspect…

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…

60 questions
nutrition
nutrition

Eating on a suppressed appetite: hitting nutritional targets inside a small energy budget, micronutrient risk, meal structure, and what the trial…

100 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
asked by elke_brunner 17k · 38 days ago
20 votes1 answer3.1k views
What is the arithmetic to convert 50 mg in 2.5 mL into units on a U-100 scale?

For reference: 50 mg · 2.5 mL. I would like the arithmetic checked rather than the conclusion asserted. I have deliberately not used an online calculator because I…

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 sinead_gaffney 28k · 33 days ago
12 votes5 answers3.5k views
Is a 98.8% result from Janoshik comparable to 96.4% from Medutest?

What I have: 98.8% · Janoshik · 96.4% · Medutest. I want to know what the trade-off actually is rather than which option is fashionable. I would rather have a…

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
janoshik
janoshik

Janoshik Analytical, an independent third-party testing laboratory widely used by this community for HPLC purity, identity and quantified content…

139 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 leah_ferrers 12k · 2 months ago
22 votes 5 answers2.8k views
Is 8 mg in 0.5 mL of sterile water for injection a sensible presentation for ecnoglutide?

Details up front: 8 mg · 0.5 mL · sterile water for injection · ecnoglutide. This is a planning question. I know what my options are; I do not know how to weigh them.…

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
sterile-water
sterile-water

Preservative-free sterile water for injection: appropriate for a single-withdrawal presentation, a poor choice for anything you intend to open…

35 questions
ecnoglutide
ecnoglutide

A long-acting GLP-1 receptor agonist with a cAMP-biased signalling profile. A niche tag, mostly used for mechanism questions about biased agonism…

223 questions
asked by swab_stopper 8.8k · 27 days ago
14 votes 5 answers3.3k views
Does splitting a 0.25 mg weekly dose of liraglutide across two administrations change anything?

Concretely: 0.25 mg · liraglutide. This is one of those things that everyone repeats and nobody derives. This matters practically, not just academically, because it…

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
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 drawn_and_capped 12k · 4 months ago
17 votes 5 answers4.2k views
Is there any published stability data for cagrilintide at 4 °C?

Numbers first: cagrilintide · 4 °C. I am asking for verification rather than opinion, ideally with something I can read myself. It is possible the evidence exists and…

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
clinical-trials
clinical-trials

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

745 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 Dr_Wren_Halliday 19k · 27 days ago
20 votes 5 answers4k views
Is 15 mg weekly a defensible maintenance dose for dulaglutide?

Details up front: 15 mg · dulaglutide. 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 viable…

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
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 petra_hovland 35k · 2 months ago
16 votes 5 answers7k views
Does deamidation produce a resolvable peak on a wide-pore C18 column, or does it co-elute?

The specifics, since they change the answer: deamidation · a wide-pore C18 column. I would like the mechanism, because I want to be able to reason about the cases…

hplc
hplc

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

503 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
peptide-stability
peptide-stability

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

908 questions
asked by nine_point_nine 60k · 4 months ago
14 votes 5 answers6k views
How long does a Xi’an to the Netherlands lane usually take with tracking?

The particulars: Xi’an · the Netherlands. I want to understand what this actually establishes, as opposed to what it is being used to imply. My concern is that I am…

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
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…

196 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
asked by colm_dunphy 8.2k · 29 days ago
2 votes2 answers798 views
Why is a fixed-ratio co-formulation not the same as two separate injections?

I have read the medicinal chemistry paper and the pharmacology paper, which helped and did not finish the job. I understand the observation; what I do not understand…

cagrisema
cagrisema

A fixed-ratio combination of cagrilintide, a long-acting amylin analogue, with semaglutide, studied in the REDEFINE programme. Questions here…

8 questions
amylin
amylin

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

237 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 carys_meredith 12k · 17 days ago