Retatrutide Reconstitution with 180 mL Bacteriostatic Water
When reconstituting a 36 mg vial of retatrutide with 180 mL of bacteriostatic water, the resulting concentration is 0.2 mg/mL (36 mg ÷ 180 mL = 0.2 mg/mL); therefore, you would need 5 mL for a 1 mg dose and 10 mL for a 2 mg dose.
Concentration Calculation
- Final concentration: 36 mg ÷ 180 mL = 0.2 mg/mL 1
- This is a straightforward dilution where the total drug amount is divided by the total volume of diluent
Dosing Volumes
For 1 mg dose:
- Volume needed: 1 mg ÷ 0.2 mg/mL = 5 mL 1
For 2 mg dose:
- Volume needed: 2 mg ÷ 0.2 mg/mL = 10 mL 1
Preparation Requirements
Sterile technique is mandatory throughout the reconstitution process:
- Sanitize the preparation area with 70% isopropanol without added ingredients like dyes or glycerin 2
- Thoroughly wash hands to wrists with detergent or soap and potable water, or use sanitizing agents containing 70% isopropanol 2
- Sanitize the vial stopper with isopropanol before needle puncture 2
- Avoid direct contact contamination of sterile needles and syringes 2
Storage and Handling
- Refrigerate the reconstituted solution at 4°C to minimize potency loss 2
- Label clearly with medication name, concentration (0.2 mg/mL), date and time of preparation, and expiration time 1
- Shake well before each use to ensure proper mixing 2
- Perform visual inspection for physical integrity after mixing 2
Important Caveats
- The large dilution volume (180 mL) creates a very dilute concentration requiring larger injection volumes, which may not be practical for subcutaneous administration 3, 4
- Standard retatrutide dosing in clinical trials used once-weekly subcutaneous injections with therapeutic doses ranging from 1 mg to 12 mg 3, 4
- If not used immediately, discard the reconstituted solution after 24 hours when stored at refrigeration temperature 1