GLPHubglpresearchhub.com
Read-only archive. GLP Research Hub is a static community record — nothing here is for sale, no account is needed, and no vote you cast is counted. Why?
Single comment threadYou are looking at one branch of someone explain bacteriostatic water to me like I have not read a paper in years — 34 comments in the full submission. View in context.
724
c/reconstitution·submitted 28 days ago by u/emil_zamora

someone explain bacteriostatic water to me like I have not read a paper in years

Mathbranch of 6 comments

someone explain bacteriostatic water to me like I have not read a paper in years. I am not trying to be the "source?" guy. I would just like a source. The lyophilised cake displaces a small volume, so the true concentration is very slightly lower than the arithmetic suggests. It is a fraction of a percent and it is…

Read the full submission and all 34 comments →

This branch

6 comments, started 27 days ago
u/saskia_rahimi46 points·27 days ago

The arithmetic in full: concentration is mass over volume, so 10mg into 2mL gives 5mg/mL. A U-100 syringe is graduated at 100 units per millilitre, so 5mg is 5 divided by 5 millilitres, which is 100 units.

replysharereportpermalink
u/vial_math_veraMOD23 points·27 days ago

Left up and flaired Explainer — the numbers in this one check out.

replysharereportpermalink
u/arto_falk0 points·27 days ago

Correction: that gives 30 units, not what you have written. 5mg into 1mL is 5mg/mL and the division follows from there.

replysharereportpermalink
u/emil_zamoraOP14 points·27 days ago·edited

The dead space question sent me down a rabbit hole for a week. It is a fraction of a unit and it is the same every draw.

replysharereportpermalink
u/janek_ferrari20 points·27 days ago·edited

That is sterile water, not bacteriostatic. Same appearance, different product, and it matters for a multi-draw vial.

replysharereportpermalink
u/lyophile_lou9 points·26 days ago

the powder cake sits at the bottom, the volume you add is the volume that counts

replysharereportpermalink

← back to the whole thread

About c/reconstitution

The arithmetic and the technique. Bacteriostatic versus sterile water, reconstitution volume as a concentration choice, converting mg/mL into insulin-syringe units, dead space, swirl-not-shake, stopper coring, and how long a reconstituted vial is actually good for. Math errors get corrected fast and politely.

88kmembers
130submissions
Aug 2023created
submissions / month, last year
Sponsored

Janoshik Analytical

Independent HPLC and mass spec. The number you get is the number they found.

janoshik.comSponsored

GL Biochem (Shanghai)

Custom peptides and amino acids direct from the manufacturer since 1998. ISO 9001 / cGMP. Batch COA every order.

glbiochem.net
More in c/reconstitution
c/reconstitution rules
  1. Show your numbers. "How many units?" with no mg and no mL cannot be answered.
  2. Never post a calculation as advice without stating the concentration it assumes.
  3. No sterile-compounding-for-others discussion. Personal handling only.
  4. Independent community. Nobody here sells anything, and anyone who tries is banned.
  5. Not medical advice. Describe what you did; never prescribe to a stranger.
  6. Claims need evidence. Batch numbers, dated screenshots, independent test reports, or a citation.
  7. No referral links, discount codes or affiliate URLs. Permanent ban, no appeal.
  8. No contact handles, wallet addresses or tracking numbers — they identify people.
  9. Be recognisably decent. Disagree hard, insult nobody.
Full rules and how they are enforced →
Moderators
u/bac_water_banditu/vial_math_verau/units_not_mgu/swirl_dont_shake
Volunteers. Unpaid, unaffiliated, and reachable through modmail only.
Before you read on

Several compounds discussed on GLP Research Hub are sold for research use only and are not approved for human use anywhere. Nothing here is medical advice and none of it is written by your clinician. If a post reads like an instruction, treat it as a description of what one stranger did.

Full disclaimer →