Retatrutide Reconstitution Concentration
When reconstituting 36 mg of retatrutide in 360 mL of bacteriostatic water, the final concentration is 0.1 mg/mL.
Calculation Method
The concentration calculation follows basic pharmaceutical dilution principles:
- Concentration = Total drug amount ÷ Total volume
- 36 mg ÷ 360 mL = 0.1 mg/mL 1
Practical Considerations for This Dilution
Volume and Stability Concerns
- This represents an extremely high dilution ratio (1:10 ratio of standard reconstitution practices), which may compromise drug stability 1
- Standard reconstitution guidelines recommend against over-dilution, as it can jeopardize stability and necessitate impractically large injection volumes 1
- Reconstituted peptide solutions have limited stability and should not be retained long-term unless specific stability data support extended use 1, 2
Storage and Handling
- Store the reconstituted solution at 2-8°C (36-46°F) 1
- Bacteriostatic water contains approximately 0.9% benzyl alcohol preservative, permitting multi-dose use for up to 28 days when refrigerated 1
- Label the vial with concentration (0.1 mg/mL), reconstitution date, and beyond-use date 1
- Discard if the solution becomes discolored or contains particulate matter 1
Clinical Context
- Retatrutide clinical trials used doses ranging from 1 mg to 12 mg weekly for obesity and type 2 diabetes 3, 4
- At 0.1 mg/mL concentration, administering even a 1 mg dose would require 10 mL injection volume, which is impractical for subcutaneous administration 1
- Standard subcutaneous injection volumes should not exceed 1-2 mL per site 1
Common Pitfalls to Avoid
- Never use sterile water without preservative for multi-dose vials, as this raises contamination risk 1
- Do not reconstitute powder that has been exposed to moisture or appears discolored prior to mixing 1
- Maintain strict aseptic technique: sanitize vial stopper with 70% isopropanol, inject diluent slowly down the vial side, and gently swirl (do not shake vigorously) 1
- Perform visual inspection after mixing for clarity and absence of particulate matter 1