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Revisiting: Bug report: the reconstitution calculator and a rounding edge case

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cohort_driftTL3Regular19 Nov 2024#1

Revisiting: Bug report: the reconstitution calculator and a rounding edge case — setting out what I have, and where I think it stops being reliable.

Working through the identity arithmetic and I would like it checked.

retatrutide has a monoisotopic mass close to 4731.3 Da. On an electrospray instrument I would expect to see the multiply charged series rather than the intact singly charged ion, so for the doubly charged species I calculate (4731.3 + 2 x 1.00728) / 2, and for the triply charged the analogous expression.

The observed values in the report sit within a few ppm of those. My question is what that actually establishes, because I have seen people treat a mass match as a purity result and I do not think it is one.

10 likes 20mo

j.marchettiTL2 Moderator22 Nov 2024#2

Reporting bugs: if you notice a calculator giving wrong results, report it in this subcategory. Bugs are fixed when identified.

0 likes 20mo

figure_reviewTL2Member24 Nov 2024#3

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 been repeating something I had not checked carefully enough.

0 likes 20mo

s.lindqvistTL2 Moderator25 Nov 2024#4

Precision and significant figures: the calculators do not round to match your input precision. If you input values to one decimal place, the output might have more. Use significant figures appropriate to your input precision.

21 likes 20mo

k.farrugiaTL3Regular27 Nov 2024#5

I read post #3 twice before replying, because I had assumed the opposite.

Units: all calculators explicitly require units to be stated. This prevents the decimal-point errors that come from forgetting units. Always verify units in and out.

2 likes 20mo

m.yildizTL2 Moderator28 Nov 2024#6

k.farrugia, post #5: I read post #3 twice before replying, because I had assumed the opposite. Units: all calculators explicitly require units to be stated. This prevents the decimal-point errors that come from forgetting units. Always verify units in and out. Go to post

This follows post #3 rather than contradicting it.

Thank you for the correction. I have edited my earlier post with a note rather than silently, so the thread still makes sense to read. The error was mine and it was the kind that comes from remembering a figure instead of looking it up.

0 likes in reply to #5 20mo

lyophil_marginTL3Regular30 Nov 2024 · edited#7

s.lindqvist, post #4: Precision and significant figures: the calculators do not round to match your input precision. If you input values to one decimal place, the output might have more. Use significant figures appropriate to your input precision. Go to post

Reconstitution calculator: enter vial mass, final volume target, and the calculator tells you concentration and syringe mark for a given dose. Useful for double-checking arithmetic when you are doing it by hand.

29 likes in reply to #4 20mo

a.amankwahTL2 Moderator1 Dec 2024#8

Dose equivalence calculator: compounds have different potencies. The calculator is provided with a caveat: "equivalence" is not precise and individual response varies. It is a rough starting point, not a dose prescription.

14 likes 20mo

e.mikkelsenTL23 Dec 2024#9

Collapsed as off-topic by two members at trust level 3 or above

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 been repeating something I had not checked carefully enough.

d.nwosuTL2 Moderator4 Dec 2024#10

Picking up post #7: that is the part I would want checked first.

Mass error checking: enter your observed mass and theoretical mass and check whether the difference in ppm is within reasonable bounds for your instrument. Useful sanity check on LC-MS results.

0 likes 20mo

f.abrahamsenTL25 Dec 2024#11

Collapsed as off-topic by two members at trust level 3 or above

Picking up post #8: that is the part I would want checked first.

Storage lookup: which conditions (temperature, time) are you considering storing in, and how much stability loss is expected? The calculator gives a rough estimate based on typical stability data. Not a substitute for your compound's specific stability data.

ka.haddadTL2 Moderator6 Dec 2024#12

a.amankwah, post #8: Dose equivalence calculator: compounds have different potencies. The calculator is provided with a caveat: "equivalence" is not precise and individual response varies. It is a rough starting point, not a dose prescription. Go to post

Coming back to post #10, because the follow-up matters more than the original answer.

Offline use: all calculators are written in JavaScript and can be downloaded and run offline if desired. They do not require internet connectivity to function.

16 likes in reply to #8 20mo

g.haalandTL3Regular7 Dec 2024#13

Titration planning: a calculator that shows you the escalation schedule for different starting and ending doses can help you visualize your path. Actual path might be slower or adjusted for tolerability.

32 likes 20mo

s.beaulieuTL2 Moderator9 Dec 2024#14

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 been repeating something I had not checked carefully enough.

0 likes 20mo

OkaforTL3Regular10 Dec 2024 · edited#15

This follows post #12 rather than contradicting it.

The calculators maintained on this site are open-source and verifiable. They are intended to check arithmetic, not to replace medical judgement. Using them is optional and they are provided for convenience.

3 likes 20mo

il.dumitruTL2 Moderator11 Dec 2024#16

Offline use: all calculators are written in JavaScript and can be downloaded and run offline if desired. They do not require internet connectivity to function.

11 likes 20mo

OTeixeiraTL3Regular12 Dec 2024#17

figure_review, post #3: 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 been repeating something I had not checked carefully enough. Go to post

Reporting bugs: if you notice a calculator giving wrong results, report it in this subcategory. Bugs are fixed when identified.

24 likes in reply to #3 20mo

i.oseiTL2 Moderator13 Dec 2024#18

Why calculators are not medical advice: they do arithmetic. Medical decisions are not arithmetic. A calculator that says a certain dose is "compatible with" a certain body mass is not a prescription.

0 likes 19mo

a.kowalskiTL2 Moderator14 Dec 2024#19

15 likes in reply to #5 19mo

e.piresTL215 Dec 2024#20

Collapsed as off-topic by two members at trust level 3 or above

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 records is not any individual result; it is that they are dated and consecutive.

CFairweatherTL1Member16 Dec 2024 · edited#21

11 likes 19mo

a.cabreraTL2 Moderator17 Dec 2024#22

For anyone arriving from a search: the marked solution above is the direct answer, and the replies underneath it add the caveats that make it safe to use.

3 likes 19mo

citation_peakTL3Regular18 Dec 2024#23

On post #19 — agreed on the reasoning, with one qualification.

0 likes 19mo

s.ivaturiTL2 Moderator19 Dec 2024#24

d.nwosu, post #10: Picking up post #7: that is the part I would want checked first. Mass error checking: enter your observed mass and theoretical mass and check whether the difference in ppm is within reasonable bounds for your instrument. Useful sanity check on LC-MS results. Go to post

post #23 answers the question as asked. The question underneath it is different.

Mass error checking: enter your observed mass and theoretical mass and check whether the difference in ppm is within reasonable bounds for your instrument. Useful sanity check on LC-MS results.

24 likes in reply to #10 19mo

endpoint_lineTL3Regular21 Dec 2024#25

Units: all calculators explicitly require units to be stated. This prevents the decimal-point errors that come from forgetting units. Always verify units in and out.

17 likes in reply to #5 19mo

i.dumitruTL2 Moderator22 Dec 2024#26

7 likes 19mo

RidgewayTL3Regular23 Dec 2024#27

Worth separating two things that post #23 runs together.

0 likes 19mo

s.demirTL2 Moderator24 Dec 2024#28

33 likes 19mo

l.aaltonenTL3Regular24 Dec 2024#29

Coming back to post #27, because the follow-up matters more than the original answer.

4 likes 19mo

p.onwukaTL2 Moderator25 Dec 2024 · edited#30

Picking up post #27: that is the part I would want checked first.

0 likes 19mo

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