LL-37 Reconstitution Calculator

What is LL-37?

LL-37 is a 37-amino-acid cationic antimicrobial peptide derived from the C-terminal portion of human cathelicidin (hCAP-18). Published research has studied LL-37 in contexts of innate immunity, antimicrobial activity against bacteria and viruses, and wound healing. It is the only cathelicidin-family antimicrobial peptide identified in humans and has been the subject of extensive basic research on host defense. LL-37 is not approved by the FDA for human use. Research-grade LL-37 sold by chemical supply companies is labeled for laboratory research purposes only.

Common vial sizes

Research vendors typically offer LL-37 in 5 mg or 10 mg lyophilized vials. Reconstitution with 2–3 mL of bacteriostatic water is commonly reported.

• 5 mg vial
• 10 mg vial

Reconstitution examples

Worked examples showing exactly what a given vial, bacteriostatic water volume, and target dose produce in syringe units. All math is from the same calculator above.

• 5 mg vial + 2 mL bacteriostatic water → 2500 mcg/mL concentration.
  A 250 mcg dose = 10 units on a u-100 insulin, 1 ml (100 units) (0.1 mL).
• 5 mg vial + 2 mL bacteriostatic water → 2500 mcg/mL concentration.
  A 500 mcg dose = 20 units on a u-100 insulin, 1 ml (100 units) (0.2 mL).
• 10 mg vial + 3 mL bacteriostatic water → 3333.33 mcg/mL concentration.
  A 500 mcg dose = 15 units on a u-100 insulin, 1 ml (100 units) (0.15 mL).
• 5 mg vial + 3 mL bacteriostatic water → 1666.67 mcg/mL concentration.
  A 100 mcg dose = 6 units on a u-100 insulin, 1 ml (100 units) (0.06 mL).

Storage & shelf life

Lyophilized LL-37 is typically stored frozen for long-term storage or refrigerated for short-term use. Reconstituted solutions are commonly kept refrigerated and protected from light.

Reported half-life

Published pharmacokinetic data on systemic LL-37 is limited. Available research suggests a plasma half-life on the order of hours.