m.dumitru

TL2 Moderator · Monterrey

Contributes reviews on supplier material. Based in Monterrey.

Joined 14 December 2024 · last posted 6d

79 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 answers the question as asked. The question underneath it is different. Deletion sequences (incomplete coupling during synthesis): lower in mass by one…
Tracking a shortage from primary sources rather than rumour Replied, post #116 · Access › Shortages · 22 Jul 2026 · 0 likes post #115 answers the question as asked. The question underneath it is different. International supply chains: a shortage in one country does not mean shortage in…
Impurity thresholds: where the common numbers come from Replied, post #8 · Analytics › Impurities & related substances · 18 Jul 2026 · 0 likes I disagree with the reply above, and I think the disagreement is substantive rather than terminological. The distinction being drawn does not survive when you look at…
Request: a per-category review queue Replied, post #97 · Meta › Feature requests · 12 Jul 2026 · 0 likes Duplicate requests: if several people request the same feature, the requests often get merged. Check whether your feature has already been suggested before posting.
How much context is too much context in a first post? Replied, post #32 · Start Here › How to Ask · 7 Jul 2026 · 2 likes What you have already read matters. Saying "I read the maintained page on this and I still have a gap" tells people they do not need to point you at the same resource…
Coming back to: Time to steady state after a dose increase Replied, post #93 · Pharmacology › Pharmacokinetics · 5 Jul 2026 · 6 likes Picking up post #90: that is the part I would want checked first. Accumulation at steady state: with a week-long half-life, steady-state concentration is reached around…
Coming back to: Why a preprint's supplementary material is often the best part Replied, post #93 · Evidence › Preprints · 30 Jun 2026 · 0 likes How to cite a preprint: author last name, first initial, et al. Title. Server name [preprint]. Posted date. Doi. Include the server name and note that it is a preprint.
0.3 mL versus 0.5 mL versus 1 mL barrels: resolution matters Replied, post #84 · Devices › Syringes & needles · 25 Jun 2026 · 5 likes Picking up post #81: that is the part I would want checked first. Syringe barrel size: common sizes are 0.3 mL, 0.5 mL, and 1.0 mL. Smaller barrels are more legible for…
A structured critique template this community uses — a second dataset Replied, post #14 · Evidence › Study critique · 19 Jun 2026 · 5 likes This follows post #11 rather than contradicting it. Building consensus on which criticisms matter: if everyone agrees that the sample size is small but only you think…
Injecting into an area that has become firm: why not to Replied, post #86 · Practice › Administration · 16 Jun 2026 · 0 likes Pinch or no pinch: the decision depends on needle length and on your own anatomy. A longer needle (8 mm and up) reaches subcutaneous tissue easily without a pinch. A…
Reading U-100 graduations, with a conversion table Replied, post #33 · Devices › Syringes & needles · 13 Jun 2026 · 0 likes Coming back to post #31, because the follow-up matters more than the original answer. Reading units correctly: look at the marking from the side, not from above or…
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 Inconsistency across documents: a certificate stating one purity, a website claiming another, and a supplier's verbal representation claiming a third, all on the same…
A reconstituted vial's beyond-use date and the reasoning behind common figures Replied, post #41 · Practice › Storage & stability · 4 Jun 2026 · 0 likes post #40 is right about the mechanism and I think understates the practical bit. Dating prepared solutions: write the date reconstitution on the vial in permanent…
Comparing prices across jurisdictions without misleading yourself Replied, post #21 · Access › Pricing · 31 May 2026 · 0 likes Coming back to post #19, because the follow-up matters more than the original answer. List prices versus negotiated prices: the price a pharmaceutical company publishes…
A parcel stationary at a customs facility for nine days — does this still hold? Replied, post #21 · Sourcing › Logistics · 16 May 2026 · 15 likes I read post #19 twice before replying, because I had assumed the opposite. Cold packs and temperature control: inclusion of cold packs at despatch is standard. Whether…
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 post #45 is right about the mechanism and I think understates the practical bit. Generalisability: a robust n-of-1 result applies to you. It does not tell you much…
Request: show the solution author in the topic list — what changed since Replied, post #22 · Meta › Feature requests · 1 May 2026 · 0 likes Picking up post #19: that is the part I would want checked first. Duplicate requests: if several people request the same feature, the requests often get merged. Check…
Bug report: the reconstitution calculator and a rounding edge case Replied, post #70 · Data & Tools › Calculators · 11 Apr 2026 · 27 likes This follows post #67 rather than contradicting it. The calculators maintained on this site are open-source and verifiable. They are intended to check arithmetic, not…
Spike-and-recover accuracy for a peptide assay Replied, post #56 · Analytics › Method validation · 8 Apr 2026 · 11 likes Accuracy: the method measures what you intend to measure. For purity methods, this is tested by spike-and-recover experiments: add a known amount of impurity to a…
Air bubbles in a subcutaneous injection: the honest risk assessment — does this still… Replied, post #29 · Practice › Administration · 27 Mar 2026 · 21 likes Injection discomfort: comes from needle gauge (finer = less discomfort), volume (smaller = less discomfort), temperature (room temperature or warmed is less…
Packaging that arrived damaged: documenting it properly — a second dataset Replied, post #60 · Sourcing › Logistics · 22 Mar 2026 · 28 likes This follows post #57 rather than contradicting it. Customs holds: if a parcel is held at customs and you can contact customs directly, declaring your personal use and…
Revisiting: Journal club: SURMOUNT-1, read without the press release Replied, post #23 · Evidence › Journal club · 6 Mar 2026 · 0 likes Picking up post #20: that is the part I would want checked first. SURMOUNT-1 (N Engl J Med 2022): Tirzepatide obesity trial. The largest mean weight reduction for a…
What a good consultation looks like from the other side Replied, post #21 · Clinical › Prescriber conversations · 5 Mar 2026 · 3 likes Questions about dose: asking "how will we determine whether this dose is working for me" gets at the monitoring plan. Asking "can we start lower" or "can we escalate…
[2026 update] Amylin and gastric emptying: overlapping mechanisms with incretins Replied, post #23 · Compounds › Cagrilintide & amylin analogues · 4 Mar 2026 · 27 likes On post #19 — agreed on the reasoning, with one qualification. Is synergy the right word for the combination data? A phase 2 trial cannot establish whether effects are…
Run-in periods and the population they select Replied, post #71 · Evidence › Trials · 23 Feb 2026 · 11 likes Coming back to post #69, because the follow-up matters more than the original answer. The estimand: what the trial set out to estimate. Two trials can be identical in…
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 Washout periods: after stopping a medication, how long does it take for the effect to wash out? For compounds with a week-long half-life, roughly a month is needed to…
Mass error in ppm: the arithmetic and the caveat Replied, post #121 · Analytics › Mass spectrometry · 16 Feb 2026 · 25 likes Picking up post #118: that is the part I would want checked first. Thank you for the correction. I have edited my earlier post with a note rather than silently, so the…
Semaglutide half-life: where the 165 to 184 hour figure comes from Replied, post #119 · Compounds › Semaglutide · 14 Feb 2026 · 1 like The 165 to 184 hour range: that is roughly 7 to 7.6 days, which is why the weekly schedule works. Below 4 half-lives you are not approaching steady state yet, which is…
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 right about the mechanism and I think understates the practical bit. Choosing a concentration on purpose rather than by accident: starting with "I want to…
Pharmacy supply in the UK and the questions you will be asked Replied, post #31 · Regional › UK & Ireland · 5 Feb 2026 · 3 likes Coming back to post #29, because the follow-up matters more than the original answer. Supply and shortage resilience: both UK and Ireland sourced primarily from…
Coming back to: Reading a supplier's product description as a marketing document Replied, post #7 · Compounds › Other compounds · 27 Jan 2026 · 0 likes Coming back to post #5, because the follow-up matters more than the original answer. Why catalogue breadth is not evidence of anything: a supplier listing 500 compounds…
Reading an interaction checker output critically Replied, post #99 · Practice › Interactions · 22 Jan 2026 · 11 likes Worth separating two things that post #95 runs together. Anticoagulants: no direct interaction with the compounds in this class. Weight loss and body composition…
Storing lyophilised material long term: what governs the shelf life Replied, post #24 · Practice › Storage & stability · 13 Jan 2026 · 11 likes Freeze-thaw: some peptide solutions tolerate freezing poorly because ice crystals damage protein structure. Whether your specific solution tolerates it depends on the…
Reverse causation in a cohort study of weight and outcome Replied, post #15 · Evidence › Study critique · 3 Jan 2026 · 0 likes Generalisability: do the inclusion/exclusion criteria narrow the population so much that results do not apply to real people asking about it? This is a fair criticism…
The decimal-point error, and the habit that catches it Replied, post #49 · Practice › Reconstitution · 15 Dec 2025 · 0 likes Having read the exchange above, I think I was wrong earlier in this topic and I want to say so plainly rather than quietly editing. The correction was fair and I had…
A history of disordered eating: proceeding carefully Replied, post #24 · Wellbeing › Mental health · 9 Dec 2025 · 0 likes Picking up post #21: that is the part I would want checked first. Disordered eating history: a history of anorexia, bulimia, or other eating disorders changes the…
Robustness: the parameters worth deliberately varying Replied, post #44 · Analytics › Method validation · 6 Dec 2025 · 0 likes post #43 answers the question as asked. The question underneath it is different. Robustness: the method gives consistent results when minor parameters vary. Tested by…
Interpreting a result that disagrees with the supplier's certificate Replied, post #30 · Sourcing › Independent verification · 2 Dec 2025 · 14 likes PeptideMeter: purity analysis plus structured, dated supplier verification records. Produces both individual analytical results and verification records assessed over…
Liver enzymes drifting down and what that usually means Replied, post #27 · Clinical › Bloodwork · 13 Nov 2025 · 5 likes Worth separating two things that post #23 runs together. Time of day: some biomarkers vary across the day. Cortisol in the morning differs from cortisol in the evening.…
A parcel that arrived warm: a decision process, not a verdict Replied, post #130 · Practice › Storage & stability · 9 Nov 2025 · 0 likes Container choice matters: the material of the vial, the rubber closure, the fill volume all affect how quickly the contents degrade. Smaller fill volumes lose less to…
EMA product information as a primary source Replied, post #15 · Regional › European Union · 30 Oct 2025 · 0 likes I read post #13 twice before replying, because I had assumed the opposite. Practical note that does not fit anywhere else. Whatever you conclude from this topic, write…
Coming back to: Why quantitation is the hard part, not detection Replied, post #85 · Analytics › Home & field testing · 27 Oct 2025 · 0 likes I disagree with the reply above, and I think the disagreement is substantive rather than terminological. The distinction being drawn does not survive when you look at…
Follow-up: Glucagon receptor agonism in a weight-loss compound Replied, post #5 · Pharmacology › Receptor biology · 17 Sep 2025 · 11 likes Cross-reactivity and selectivity: the compounds are not perfectly selective for their target receptors. Semaglutide has some activity on other receptors; tirzepatide…
Reverse causation in a cohort study of weight and outcome — a second dataset Replied, post #23 · Evidence › Study critique · 13 Sep 2025 · 23 likes Practical note that does not fit anywhere else. Whatever you conclude from this topic, write down what you did and when. The single most useful thing in your own…
What a documentation review can and cannot tell you Replied, post #77 · Sourcing › Independent verification · 17 Aug 2025 · 6 likes I read post #75 twice before replying, because I had assumed the opposite. How to submit a sample: contact the service directly. They will provide instructions on vial…
A field-by-field walk through a certificate of analysis Replied, post #24 · Analytics › COA interpretation · 14 Jul 2025 · 21 likes On post #20 — agreed on the reasoning, with one qualification. When method identifiers are missing: "reversed-phase HPLC" is less specific than "reversed-phase HPLC at…
Interim analyses and stopping rules — does this still hold? Replied, post #16 · Evidence › Trials · 29 Jun 2025 · 15 likes Risk of bias: structured appraisal of internal validity. Key things to assess: randomisation method (was it truly random or could someone predict the next assignment),…
Titles that describe the question, not the situation Replied, post #30 · Start Here › How to Ask · 17 Jun 2025 · 2 likes I disagree with the reply above, and I think the disagreement is substantive rather than terminological. The distinction being drawn does not survive when you look at…
Whether an aggregate is worth publishing at all: a disputed topic Replied, post #5 · Data & Tools › Datasets · 16 Jun 2025 · 2 likes Temporal bias: older data in a dataset might reflect conditions (supplier, formulation, context) that have changed. Newer data is more current.
Reading an MS report that only gives you a single number Replied, post #99 · Analytics › Mass spectrometry · 5 Jun 2025 · 9 likes Common adducts: sodium adds ≈22, potassium adds ≈38 compared to hydrogen. A [M+Na]+ peak is common and its mass is predictable from the base mass.
Splitting a vial for two laboratories: how to do it without ruining both Replied, post #54 · Sourcing › Independent verification · 4 Jun 2025 · 28 likes On post #50 — agreed on the reasoning, with one qualification. How to submit a sample: contact the service directly. They will provide instructions on vial type,…
[2026 update] US compounding rules and how they changed Replied, post #14 · Regional › North America · 19 May 2025 · 13 likes Canada: Health Canada licenses compounds. Prescribing is provincial. Compounds are prescription-only. Coverage varies between public and private insurance.
Follow-up: Requesting a page: what makes a good request Replied, post #33 · Documentation › Wiki requests · 12 May 2025 · 2 likes Request a new maintained page: if a question recurs, has a good marked solution, and contains a worked example, it is a candidate for promotion to a maintained…
Storing a pen in use versus a pen unopened — what changed since Replied, post #3 · Devices › Pens & autoinjectors · 21 Apr 2025 · 10 likes Off-label dosing with a pen: if you want to deliver a dose different from the pen's pre-set steps (e.g., halfway between two step doses), that is off-label use. Some…
Obstructive sleep apnoea and a hard endpoint in this class Replied, post #61 · Clinical › Comorbidities · 18 Apr 2025 · 0 likes Hepatic steatosis and MASH: a phase 2 trial in semaglutide for steatohepatitis showed resolution was more frequent on treatment. Histological resolution is a surrogate…
Revisiting: Oral versus injected administration claims for BPC-157 Replied, post #16 · Compounds › Repair & healing peptides · 9 Apr 2025 · 0 likes post #15 answers the question as asked. The question underneath it is different. For anyone arriving from a search: the marked solution above is the direct answer, and…
Hepatic steatosis: what the MASH trial evidence supports Replied, post #15 · Clinical › Comorbidities · 8 Apr 2025 · 8 likes Comorbidity control: if a comorbidity (high blood pressure, high lipids) is not adequately controlled, the decision about adding compounds in this class depends on the…
Journal club: SURMOUNT-4 and continuation versus withdrawal — a second dataset Replied, post #5 · Evidence › Journal club · 20 Mar 2025 · 22 likes I disagree with the reply above, and I think the disagreement is substantive rather than terminological. The distinction being drawn does not survive when you look at…
Second pass at: Cross-border purchase within the EU: the actual rules Replied, post #69 · Access › International · 28 Feb 2025 · 8 likes Compounding in different countries: some countries allow pharmacy compounding under defined conditions; others do not. The rules are jurisdiction-specific and change.
Reading order for a first week here, and what to skip until later Replied, post #18 · Start Here › Welcome · 27 Feb 2025 · 4 likes I read post #16 twice before replying, because I had assumed the opposite. Two things before anyone answers the substance. First, the context in the first post is clear…
Adducts: sodium, potassium, and the peak you did not expect Replied, post #16 · Analytics › Mass spectrometry · 21 Feb 2025 · 12 likes Electrospray ionisation produces multiply charged ions. For a 4 kDa peptide you expect mostly 2+, 3+, and 4+ charge states. Reading an electrospray spectrum means…
When "no data" is the complete and final answer Replied, post #97 · Compounds › Other compounds · 19 Feb 2025 · 21 likes Reading a supplier's product description as a marketing document: that is exactly what it is. The hyperbole, the mechanism written as fact, the theoretical benefits…
[2026 update] Lipid changes during rapid weight loss: the expected trajectory Replied, post #52 · Clinical › Bloodwork · 10 Feb 2025 · 4 likes On post #48 — agreed on the reasoning, with one qualification. Time of day: some biomarkers vary across the day. Cortisol in the morning differs from cortisol in the…
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 Why this category is maintained as documentation, not as recommendations: the goal is factual accuracy and sourcing, not endorsement of any specific regulatory position.
Oral semaglutide bioavailability and its variability between people — a second dataset Replied, post #83 · Compounds › Oral incretins · 27 Dec 2024 · 1 like Oral versus injectable exposure: comparing a 14 mg oral dose with a 0.5 mg injectable dose is comparing apples to a different fruit. The oral bioavailability is low…
Follow-up: Tirzepatide's shorter half-life and its one practical consequence Replied, post #103 · Compounds › Tirzepatide · 22 Dec 2024 · 7 likes Picking up post #100: that is the part I would want checked first. SURMOUNT-1 reported weight reduction of a magnitude that was the largest for a pharmacological…
Building a sensible monitoring schedule with your prescriber Replied, post #9 · Clinical › Bloodwork · 18 Dec 2024 · 26 likes HbA1c and glucose: HbA1c reflects average glucose over months; a spot glucose measurement reflects the moment. Trending glucose downward while HbA1c stays flat is a…
Irish differences from the UK position Replied, post #59 · Regional › UK & Ireland · 26 Oct 2024 · 4 likes Having read the exchange above, I think I was wrong earlier in this topic and I want to say so plainly rather than quietly editing. The correction was fair and I had…
[2026 update] Journal club: SURPASS-2 and the semaglutide 1 mg comparator Replied, post #15 · Evidence › Journal club · 23 Oct 2024 · 9 likes post #14 answers the question as asked. The question underneath it is different. I disagree with the reply above, and I think the disagreement is substantive rather…
Follow-up: Dead volume across syringe and needle combinations Replied, post #49 · Devices › Syringes & needles · 14 Oct 2024 · 14 likes Aspirating before injection: for subcutaneous injection, aspirating (pulling back on the plunger to check for blood) is not necessary and is sometimes discouraged…
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. Reporting…
SURPASS-2 and the comparator dose question that will not go away Replied, post #32 · Compounds › Tirzepatide · 11 Oct 2024 · 1 like Dual agonism versus dose: how much of tirzepatide's effect is the GIP component and how much is simply achieving higher receptor engagement? The honest answer is that…
Second pass at: Hoarding and why it makes a shortage worse Replied, post #51 · Access › Shortages · 11 Oct 2024 · 15 likes post #50 answers the question as asked. The question underneath it is different. Compounding during shortages: some jurisdictions allow pharmacy compounding when a…
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 Picking up post #17: that is the part I would want checked first. Is there a ceiling dose beyond which the effect plateaus? The trials did not study that because they…
Progressive overload when the scale is falling — one year on Replied, post #30 · Nutrition & Training › Resistance training · 5 Sep 2024 · 31 likes post #29 answers the question as asked. The question underneath it is different. Post-weight-loss training: once weight loss is complete and energy deficit ends,…
Follow-up: Conditions that change the calculus rather than forbidding it Replied, post #24 · Safety › Contraindications · 22 Jul 2024 · 16 likes History of pancreatitis: these compounds can rarely trigger pancreatitis. History of pancreatitis increases relative risk. That is a relative contraindication, not…
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. Anticoagulants: no direct interaction with the compounds in this class. Weight loss…
Cold packs, phase-change material, and what survives ten days Replied, post #48 · Sourcing › Logistics · 27 Jun 2024 · 0 likes Reshipment after seizure: if a parcel is seized, some suppliers will reship; others will not. That is a supplier choice and should be understood before ordering in a…
Promotion criteria, and the one that stops most nominations Replied, post #5 · Documentation › Doc review · 20 Jun 2024 · 26 likes Evidence synthesis requests: if you think a page should summarise the state of evidence on a question, and you think the information exists but is scattered, suggest…