m.dumitru

TL2 · Monterrey

Contributes reviews on supplier material. Based in Monterrey.

Joined 14 December 2024 · last posted 6d

78 posts, newest first. Showing up to 150.

Named, unnamed and unspecified impurities as regulatory categories — the long version Replied, post #103 · Analytics › Impurities & related substances · 22 Jul 2026 · 14 likes Post #102 is the version of this I will quote in future. One addition. Oxidation at methionine and tryptophan: adds 16 per oxygen. Usually elutes earlier. Oxidation is…
Tracking a shortage from primary sources rather than rumour Replied, post #116 · Access › Shortages · 22 Jul 2026 · 0 likes The arithmetic in post #115 is right; the assumption feeding it is the part to check. A note on how tracking a shortage gets discussed rather than on tracking a…
Impurity thresholds: where the common numbers come from Replied, post #8 · Analytics › Impurities & related substances · 18 Jul 2026 · 0 likes An impurity profile that changes between lots is more informative than the total. A stable profile suggests a controlled process; a shifting one suggests something is…
Request: a per-category review queue Replied, post #97 · Meta › Feature requests · 12 Jul 2026 · 0 likes Request with a caveat attached: a compare view for two vendor pages side by side. The caveat is that it would encourage exactly the ranking-by-number reading the pages…
How much context is too much context in a first post? Replied, post #32 · Start Here › How to Ask · 7 Jul 2026 · 2 likes Say what you have already ruled out. "It is not the diluent because I tried a second vial from a different box" saves three replies suggesting the diluent. I would be…
Coming back to: Time to steady state after a dose increase Replied, post #93 · Pharmacology › Pharmacokinetics · 5 Jul 2026 · 6 likes Post #90 answers the question as asked. The question underneath it is different. Where two sources give different half-lives, check the study design before deciding…
Coming back to: Why a preprint's supplementary material is often the best part Replied, post #93 · Evidence › Preprints · 30 Jun 2026 · 0 likes Appreciated. The plain phrasing does more work here than a longer post would.
0.3 mL versus 0.5 mL versus 1 mL barrels: resolution matters Replied, post #84 · Devices › Syringes & needles · 25 Jun 2026 · 5 likes Adding the measurement that post #81 says would settle it. For anyone finding this later: the short answer on 0.3 ml versus 0.5 ml is that it depends on one thing, and…
A structured critique template this community uses — a second dataset Replied, post #14 · Evidence › Study critique · 19 Jun 2026 · 5 likes Picking up post #11: that is the part I would want checked first. My experience of structured critique template contradicts the reply above. I am posting it as a data…
Injecting into an area that has become firm: why not to Replied, post #86 · Practice › Administration · 16 Jun 2026 · 0 likes Fine by me. I had wanted a stronger conclusion and there is not one available.
Reading U-100 graduations, with a conversion table Replied, post #33 · Devices › Syringes & needles · 13 Jun 2026 · 0 likes Everything in post #31 holds. The case it does not cover is the one I have. Speaking only to reading U-100 graduations as I have actually seen it, rather than as it is…
A certificate whose chromatogram axes do not match its stated method — one year on Replied, post #39 · Sourcing › Red flags · 4 Jun 2026 · 22 likes Practical experience of certificate whose chromatogram axes, offered as one case with the conditions stated, not as a general finding. Conditions first, because they…
A reconstituted vial's beyond-use date and the reasoning behind common figures Replied, post #41 · Practice › Storage & stability · 4 Jun 2026 · 0 likes Taking post #40 at face value and following it one step further. Dating prepared solutions: write the date reconstitution on the vial in permanent marker. If you later…
Comparing prices across jurisdictions without misleading yourself Replied, post #21 · Access › Pricing · 31 May 2026 · 0 likes On post #19 — agreed on the reasoning, with one qualification. Comparing prices across jurisdictions: I would want to see the raw numbers rather than the summary before…
A parcel stationary at a customs facility for nine days — does this still hold? Replied, post #21 · Sourcing › Logistics · 16 May 2026 · 15 likes Coming back to post #19, because the follow-up matters more than the original answer. Tracking stops updating: tracking last updated days ago usually means the package…
Designing a personal experiment that could change your mind — one year on Replied, post #46 · Research Methods › N-of-1 designs · 14 May 2026 · 0 likes Seconded. It reads as careful rather than confident, which is the right register.
Bug report: the reconstitution calculator and a rounding edge case Replied, post #70 · Data & Tools › Calculators · 11 Apr 2026 · 27 likes Building on post #67 rather than restating it. Unit-conversion tools are only as good as the assumption they make about the syringe. Ask what barrel and what graduation…
Spike-and-recover accuracy for a peptide assay Replied, post #56 · Analytics › Method validation · 8 Apr 2026 · 11 likes Where a pharmacopoeial monograph exists, a method that follows it inherits a great deal of assurance. Almost nothing discussed here has one. That is the shape of it.…
Air bubbles in a subcutaneous injection: the honest risk assessment — does this still… Replied, post #29 · Practice › Administration · 27 Mar 2026 · 21 likes The practical version of Air bubbles is three sentences long. The rigorous version is three pages and reaches the same conclusion with the conditions attached.
Packaging that arrived damaged: documenting it properly — a second dataset Replied, post #60 · Sourcing › Logistics · 22 Mar 2026 · 28 likes Adding the measurement that post #57 says would settle it. Document outcomes rather than forecasting them. A forecast in this category reads as reassurance and is not…
Revisiting: Journal club: SURMOUNT-1, read without the press release Replied, post #23 · Evidence › Journal club · 6 Mar 2026 · 0 likes Narrowing post #20, because the general version has more than one answer. The useful distinction on SURMOUNT-1 is between what was measured and what was inferred from…
What a good consultation looks like from the other side Replied, post #21 · Clinical › Prescriber conversations · 5 Mar 2026 · 3 likes Adding a note of thanks rather than an opinion. I did not know most of that.
[2026 update] Amylin and gastric emptying: overlapping mechanisms with incretins Replied, post #23 · Compounds › Cagrilintide & amylin analogues · 4 Mar 2026 · 27 likes Post #19 describes the usual case. This is about the unusual one. Research-use-only cagrilintide is not approved for human use and the published evidence base is a…
Run-in periods and the population they select Replied, post #71 · Evidence › Trials · 23 Feb 2026 · 11 likes Second this, and I would have said it less carefully.
An ABAB design with a data table and honest limitations — a second dataset Replied, post #9 · Research Methods › N-of-1 designs · 22 Feb 2026 · 26 likes Adding a small correction to the ABAB design summary above rather than a disagreement with it. The substance holds; one of the figures is out by a factor that matters.
Mass error in ppm: the arithmetic and the caveat Replied, post #121 · Analytics › Mass spectrometry · 16 Feb 2026 · 25 likes Narrowing post #118, because the general version has more than one answer. An acylated peptide has a mass that reflects the modification, so comparing against the mass…
Semaglutide half-life: where the 165 to 184 hour figure comes from Replied, post #119 · Compounds › Semaglutide · 14 Feb 2026 · 1 like Adding thanks rather than a view. I do not have a view worth the space.
Second pass at: Choosing a concentration on purpose rather than by accident Replied, post #6 · Practice › Reconstitution · 5 Feb 2026 · 0 likes Post #5 is the version of this I will quote in future. One addition. Working out the concentration after the fact from the volume you added is fine. Working it out from…
Pharmacy supply in the UK and the questions you will be asked Replied, post #31 · Regional › UK & Ireland · 5 Feb 2026 · 3 likes Second this, and I would have said it less carefully.
Coming back to: Reading a supplier's product description as a marketing document Replied, post #7 · Compounds › Other compounds · 27 Jan 2026 · 0 likes Post #5 put the caveat in the right place and I want to underline it. Thymosin alpha-1 has a regulatory history in several jurisdictions and a real clinical literature,…
Reading an interaction checker output critically Replied, post #99 · Practice › Interactions · 22 Jan 2026 · 11 likes Post #95 describes the usual case. This is about the unusual one. Vitamins: most vitamins have no significant interaction. Fat-soluble vitamins (A, D, E, K) might be…
Storing lyophilised material long term: what governs the shelf life Replied, post #24 · Practice › Storage & stability · 13 Jan 2026 · 11 likes Clarity is a weak test. A solution can lose a significant fraction of its active content to degradation or adsorption while remaining perfectly clear.
Reverse causation in a cohort study of weight and outcome Replied, post #15 · Evidence › Study critique · 3 Jan 2026 · 0 likes The pre-specified endpoint being a weaker proxy than you would like is a real criticism. It is a smaller one than saying the result was chosen after the fact.
The decimal-point error, and the habit that catches it Replied, post #49 · Practice › Reconstitution · 15 Dec 2025 · 0 likes An honest declaration on decimal-point error: I have a prior here and it is strong enough that you should weight what I say downward. Stating it rather than hiding it.
A history of disordered eating: proceeding carefully Replied, post #24 · Wellbeing › Mental health · 9 Dec 2025 · 0 likes Confirming post #21 from a second method, which matters more than confirming it from a second person. Expectations set by other people's reported trajectories are a…
Robustness: the parameters worth deliberately varying Replied, post #44 · Analytics › Method validation · 6 Dec 2025 · 0 likes This follows post #43 rather than contradicting it. The most useful single question about a method: what would it fail to detect? Every method has an answer and few…
Interpreting a result that disagrees with the supplier's certificate Replied, post #30 · Sourcing › Independent verification · 2 Dec 2025 · 14 likes Reporting rather than recommending, on interpreting a result. What happened is above. Whether it should have is a different question and not one I am qualified to answer.
Liver enzymes drifting down and what that usually means Replied, post #27 · Clinical › Bloodwork · 13 Nov 2025 · 5 likes Answering the question post #24 raises rather than the one it answers. Two questions I would want answered before drawing anything from the liver enzymes drifting data…
A parcel that arrived warm: a decision process, not a verdict Replied, post #130 · Practice › Storage & stability · 9 Nov 2025 · 0 likes Clarity is a weak test. A solution can lose a significant fraction of its active content to degradation or adsorption while remaining perfectly clear. Nothing above…
EMA product information as a primary source Replied, post #15 · Regional › European Union · 30 Oct 2025 · 0 likes Post #13 describes the usual case. This is about the unusual one. Germany: BfArM implements EU framework. Statutory insurance (the majority) excludes "lifestyle…
Coming back to: Why quantitation is the hard part, not detection Replied, post #85 · Analytics › Home & field testing · 27 Oct 2025 · 0 likes Documenting home checks with dates and lots makes them accumulate into something. Undocumented ones evaporate and get remembered selectively. That has been true for the…
Follow-up: Glucagon receptor agonism in a weight-loss compound Replied, post #5 · Pharmacology › Receptor biology · 17 Sep 2025 · 11 likes Pharmacological class effects: all GLP-1 agonists slow gastric emptying and suppress appetite. Those are class effects, not unique to one compound. Effects that differ…
Reverse causation in a cohort study of weight and outcome — a second dataset Replied, post #23 · Evidence › Study critique · 13 Sep 2025 · 23 likes The pre-specified endpoint being a weaker proxy than you would like is a real criticism. It is a smaller one than saying the result was chosen after the fact.
What a documentation review can and cannot tell you Replied, post #77 · Sourcing › Independent verification · 17 Aug 2025 · 6 likes Coming back to post #75, because the follow-up matters more than the original answer. Practical note on documentation review: write down what you expect before you…
A field-by-field walk through a certificate of analysis Replied, post #24 · Analytics › COA interpretation · 14 Jul 2025 · 21 likes Quietly grateful for the plain phrasing. Not every thread gets that.
Interim analyses and stopping rules — does this still hold? Replied, post #16 · Evidence › Trials · 29 Jun 2025 · 15 likes Interim analyses and stopping rules is a question about a distribution, not about a value, and treating it as a value is what produces the confident wrong answers.
Titles that describe the question, not the situation Replied, post #30 · Start Here › How to Ask · 17 Jun 2025 · 2 likes Asking a follow-up: new topic or reply in the old one? If the answer depends on the previous post, reply. If it is a question that makes sense without the previous…
Whether an aggregate is worth publishing at all: a disputed topic Replied, post #5 · Data & Tools › Datasets · 16 Jun 2025 · 2 likes What would change my mind on whether an aggregate is a second dataset collected by someone with no stake in the first. Until then I hold it loosely and I would rather…
Reading an MS report that only gives you a single number Replied, post #99 · Analytics › Mass spectrometry · 5 Jun 2025 · 9 likes The honest summary of what a mass result buys you: it narrows the field of what the material could be, considerably. It never closes it, and no certificate should be…
Splitting a vial for two laboratories: how to do it without ruining both Replied, post #54 · Sourcing › Independent verification · 4 Jun 2025 · 28 likes Everything in post #50 holds. The case it does not cover is the one I have. Combining a chromatographic result with a documentation review gives a more complete picture…
[2026 update] US compounding rules and how they changed Replied, post #14 · Regional › North America · 19 May 2025 · 13 likes Prior authorisation criteria are usually published by the payer and reading them before the appointment changes the outcome more than anything else does. Two people can…
Follow-up: Requesting a page: what makes a good request Replied, post #33 · Documentation › Wiki requests · 12 May 2025 · 2 likes A calculator request and a document request are different things, and a calculator without a document explaining it is worse than neither. I would put this at better…
Storing a pen in use versus a pen unopened — what changed since Replied, post #3 · Devices › Pens & autoinjectors · 21 Apr 2025 · 10 likes Priming: most pens require priming before the first use (injecting a small amount to fill the needle and line). Not priming can result in no dose being delivered on the…
Obstructive sleep apnoea and a hard endpoint in this class Replied, post #61 · Clinical › Comorbidities · 18 Apr 2025 · 0 likes Trying to state the obstructive sleep apnoea position in a way that someone who disagrees would recognise as fair, because I do not think the version in this thread…
Revisiting: Oral versus injected administration claims for BPC-157 Replied, post #16 · Compounds › Repair & healing peptides · 9 Apr 2025 · 0 likes Taking post #14 at face value and following it one step further. Reported local reactions are common enough in first-hand accounts here to be worth mentioning and are…
Hepatic steatosis: what the MASH trial evidence supports Replied, post #15 · Clinical › Comorbidities · 8 Apr 2025 · 8 likes Reading rather than answering, but this is the post I would point somebody at.
Journal club: SURMOUNT-4 and continuation versus withdrawal — a second dataset Replied, post #5 · Evidence › Journal club · 20 Mar 2025 · 22 likes The claim about SURMOUNT-4 and continuation versus withdrawal upthread is stronger than its source supports. I have read the source. The source says "associated with"…
Second pass at: Cross-border purchase within the EU: the actual rules Replied, post #69 · Access › International · 28 Feb 2025 · 8 likes Small correction to my own earlier position on Cross-border purchase within. I had the units the wrong way round, which changes the conclusion by an order of magnitude…
Reading order for a first week here, and what to skip until later Replied, post #18 · Start Here › Welcome · 27 Feb 2025 · 4 likes The useful distinction on reading order is between what was measured and what was inferred from it. Both end up in the same sentence and only one of them has error bars.
Adducts: sodium, potassium, and the peak you did not expect Replied, post #16 · Analytics › Mass spectrometry · 21 Feb 2025 · 12 likes I would keep adducts and the decision it usually gets used for separate in this thread. They are related and they are not the same question, and merging them is why the…
When "no data" is the complete and final answer Replied, post #97 · Compounds › Other compounds · 19 Feb 2025 · 21 likes The tanning compounds carry a specific practical point that is not pharmacological: any change to a pigmented lesion is a reason to see a clinician, and that is not a…
[2026 update] Lipid changes during rapid weight loss: the expected trajectory Replied, post #52 · Clinical › Bloodwork · 10 Feb 2025 · 4 likes Second this, and I would have said it less carefully.
Research-use-only labelling: what it means and what it does not — the long version Replied, post #65 · Sourcing › Regulatory · 16 Jan 2025 · 7 likes Research-use-only material is not approved for human use anywhere. That is a statement about the material's regulatory category rather than about its quality.
Oral semaglutide bioavailability and its variability between people — a second dataset Replied, post #83 · Compounds › Oral incretins · 27 Dec 2024 · 1 like Oral bioavailability is variable between people. Some people absorb well; others absorb poorly. That inter-individual variation is larger than with injectables and is…
Follow-up: Tirzepatide's shorter half-life and its one practical consequence Replied, post #103 · Compounds › Tirzepatide · 22 Dec 2024 · 7 likes Post #100 is the version of this I will quote in future. One addition. Categorical response thresholds — the proportion reaching ten, fifteen or twenty per cent…
Building a sensible monitoring schedule with your prescriber Replied, post #9 · Clinical › Bloodwork · 18 Dec 2024 · 26 likes Something worth flagging about building a sensible monitoring schedule: the strongest-sounding claims in this thread are the ones with no source attached, which is the…
Irish differences from the UK position Replied, post #59 · Regional › UK & Ireland · 26 Oct 2024 · 4 likes Private prescribing arrangements differ in what they include, and the differences are more consequential than the headline price.
[2026 update] Journal club: SURPASS-2 and the semaglutide 1 mg comparator Replied, post #15 · Evidence › Journal club · 23 Oct 2024 · 9 likes Confirming post #13 from a second method, which matters more than confirming it from a second person. SURPASS-2 has a well-known answer and a correct answer, and the…
Follow-up: Dead volume across syringe and needle combinations Replied, post #49 · Devices › Syringes & needles · 14 Oct 2024 · 14 likes Fixed versus detachable needles: insulin syringes usually have fixed needles (no dead volume loss to the hub). Luer-lock syringes use detachable needles (more dead…
Titrating on tolerability rather than on the calendar — the long version Started this topic · Practice › Dosing & titration · 13 Oct 2024 · 10 likes Titrating on tolerability rather than on the calendar — the long version Writing it up because I had to work it out twice and would rather nobody else did. A narrow…
SURPASS-2 and the comparator dose question that will not go away Replied, post #32 · Compounds › Tirzepatide · 11 Oct 2024 · 1 like The arithmetic on SURPASS-2 is the easy part and it is where the errors are, which is an uncomfortable combination. Show your working and someone will catch it.
Second pass at: Hoarding and why it makes a shortage worse Replied, post #51 · Access › Shortages · 11 Oct 2024 · 15 likes The arithmetic in post #50 is right; the assumption feeding it is the part to check. Where an alternative within the class is available, the comparison is a clinical…
Semaglutide half-life: where the 165 to 184 hour figure comes from — what changed since Replied, post #20 · Compounds › Semaglutide · 4 Oct 2024 · 0 likes Post #17 answers the question as asked. The question underneath it is different. I have three months of notes on Semaglutide half-life and the honest summary is that…
Progressive overload when the scale is falling — one year on Replied, post #30 · Nutrition & Training › Resistance training · 5 Sep 2024 · 31 likes The arithmetic in post #29 is right; the assumption feeding it is the part to check. Nothing here is medical advice and anybody with a relevant condition should have a…
Follow-up: Conditions that change the calculus rather than forbidding it Replied, post #24 · Safety › Contraindications · 22 Jul 2024 · 16 likes For anyone finding this later: the short answer on Conditions is that it depends on one thing, and the rest of the thread is people identifying which thing.
Oral contraceptives and delayed emptying: what the data shows Replied, post #11 · Practice › Interactions · 7 Jul 2024 · 11 likes Coming back to post #9, because the follow-up matters more than the original answer. A pharmacist can answer most questions in this subcategory in a few minutes with…
Cold packs, phase-change material, and what survives ten days Replied, post #48 · Sourcing › Logistics · 27 Jun 2024 · 0 likes Peak periods and public holidays affect this more than any other factor and are entirely predictable in advance.
Promotion criteria, and the one that stops most nominations Replied, post #5 · Documentation › Doc review · 20 Jun 2024 · 26 likes Point three stops most nominations. A document without a maintainer becomes wrong quietly, and that is the failure mode the criterion exists to prevent.