A vial that will not fully dissolve: check in order: is the diluent genuinely room temperature (some preservatives crystallise in cold), is the vial being warmed gently rather than shaken hard, is the injection technique clean, is the vial integrity intact. Work through that checklist before concluding the powder is insoluble.
A 10 mg vial reconstituted three different ways, compared posts 31–35
This is a continuation of a long topic, addressed by post number rather than by page. Start at post 1.
Over-dilution: if your target dose is 0.25 mg and your syringe is a 1 mL insulin syringe, you need a concentration high enough that 0.25 mg fits on the scale. A 0.25 mg/mL solution requires drawing the entire 1 mL syringe — not readable. A 5 mg/mL solution requires drawing 50 μL — also not practical on an insulin syringe.
I read post #31 twice before replying, because I had assumed the opposite.
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.
This follows post #31 rather than contradicting it.
Reconstituting a multi-strength kit: if a kit contains 5 mg, 10 mg, 15 mg vials and you are reconstituting all of them, writing the concentration on each vial in permanent marker as you go is the single most useful thing you can do to avoid dose errors later.
Why "add 2 mL" is not an instruction: the powder in the vial takes up space. "Add 2 mL to a 10 mL vial" and "add 2 mL of diluent so the final volume is approximately 2 mL" are different instructions. Stating the final target volume is clearer than stating the diluent added.
Suggested topics
| Topic | Participants | Replies | Views | Activity |
|---|---|---|---|---|
|
A 5 mg vial and a 0.25 mg dose: the arithmetic in full — what changed since
Posting this under the heading it deserves: A 5 mg vial and a 0.25 mg dose: the arithmetic in full — what changed since Everything below is what sits behind that. I have read the maintained page on this and I…
|
+86 | 93 | 25k | 13mo |
|
Swirling versus inverting versus leaving it alone
On the subject in the title: Swirling versus inverting versus leaving it alone Working notes rather than a conclusion. I have read the maintained page on this and I still have a gap, so I am asking rather…
|
2 | 18k | 18mo | |
|
Reconstitution volumes that produce round numbers, tabulated
Reconstitution volumes that produce round numbers, tabulated — setting out what I have, and where I think it stops being reliable. Practical question with the units stated, because I have seen how quickly…
|
+103 | 112 | 1.7k | 3mo |
|
A 5 mg vial and a 0.25 mg dose: the arithmetic in full — the long version
On the subject in the title: A 5 mg vial and a 0.25 mg dose: the arithmetic in full — the long version Working notes rather than a conclusion. Reporting something rather than asking about it, in case the…
|
+160 | 165 | 1.9k | 12mo |
|
Checking someone else's arithmetic: a worked example thread
Checking someone else's arithmetic: a worked example thread Writing it up because I had to work it out twice and would rather nobody else did. Practical question with the units stated, because I have seen how…
|
+74 | 78 | 895 | 11mo |
Related topics — sharing the tags bacteriostatic water, worked example, concentration maths
| Topic | Participants | Replies | Views | Activity |
|---|---|---|---|---|
|
A ten-fold dose error caught before injection
A ten-fold dose error caught before injection — setting out what I have, and where I think it stops being reliable. Reporting something rather than asking about it, in case the pattern is useful to anyone…
|
+95 | 103 | 26k | 10mo |
|
About the Formulation chemistry category
Buffers, pH, isotonicity, preservatives, lyophilisation and excipient function. This post is a community wiki: any member at trust level 3 or above can edit it, and every edit is recorded with its author and…
|
4 | 4.5k | 18mo | |
|
Second pass at: Asking a follow-up: new topic or new reply?
The question in the title: Second pass at: Asking a follow-up: new topic or new reply? I will give what I have already checked below so nobody repeats it. I want to check my reasoning rather than get a…
|
4 | 81 | 8mo | |
|
Washout: how long is long enough, and for what purpose
Washout: how long is long enough, and for what purpose — setting out what I have, and where I think it stops being reliable. A documentation question rather than an analytical one. I have a certificate in…
|
+63 | 70 | 13k | 10mo |
|
Rewriting my first post: a before-and-after, with commentary — what changed since
Posting this under the heading it deserves: Rewriting my first post: a before-and-after, with commentary — what changed since Everything below is what sits behind that. I want to check my reasoning rather…
|
+15 | 19 | 12k | 13h |