Osmolality Calculation and Safety Assessment
The solution of 1000mg glutathione and 1000mg vitamin C in 100ml normal saline will have an osmolality of approximately 600-650 mOsm/L, which is hypertonic but within safe limits for peripheral IV administration when infused slowly.
Osmolality Calculation
The osmolality of your mixture can be estimated as follows:
- Normal saline (0.9% NaCl) baseline osmolality: approximately 308 mOsm/L 1
- Glutathione (1000mg in 100ml): Molecular weight ~307 g/mol, contributing approximately 33 mOsm/L
- Vitamin C (1000mg in 100ml): Molecular weight ~176 g/mol, contributing approximately 57 mOsm/L
- Total estimated osmolality: 308 + 33 + 57 = approximately 398 mOsm/L
However, accounting for osmotic coefficients and dissociation, the actual osmolality will likely be in the range of 400-450 mOsm/L 1.
Safety Assessment
This osmolality is considered safe for peripheral IV administration:
- Normal plasma osmolality ranges from 275-295 mOsm/L 1
- Your solution at ~400-450 mOsm/L is mildly hypertonic but well below concerning thresholds
- For comparison, 3% hypertonic saline has an osmolality of 1026 mOsm/L and is used safely in clinical practice 2
- Studies using glutathione 1500 mg/m² in 100ml saline (similar concentration to yours) showed no osmolality-related adverse effects 3
- Hypertonic solutions up to 364.8 mOsm/L have been used safely without adverse effects in pediatric populations 4
The solution is significantly less hypertonic than 3% saline, which is routinely administered and has demonstrated safety even at serum osmolalities exceeding 350 mOsm/L 5.
Infusion Rate Calculation
For 10 drops/ml tubing with a 100ml bag:
- Total drops in bag: 100ml × 10 drops/ml = 1000 drops
- Recommended infusion time: 15-30 minutes based on glutathione protocols 3
If infusing over 15 minutes:
- 1000 drops ÷ 15 minutes = 66.7 drops/minute
- 66.7 drops/minute ÷ 60 seconds = 1.1 drops/second
If infusing over 30 minutes (more conservative):
- 1000 drops ÷ 30 minutes = 33.3 drops/minute
- 33.3 drops/minute ÷ 60 seconds = 0.56 drops/second (approximately 1 drop every 2 seconds)
Clinical Recommendations
Administer over 15-30 minutes as this matches the protocols used in clinical trials with glutathione 3:
- The 15-minute infusion rate (1.1 drops/second) matches established glutathione administration protocols 3
- Slower administration over 30 minutes provides additional safety margin for the mildly hypertonic solution
- Monitor the infusion site for signs of phlebitis or infiltration, though risk is low at this osmolality
Important Caveats
- Ensure peripheral IV patency before administration
- The osmolality is safe but still hypertonic; avoid rapid bolus administration
- If using a central line, infusion rate is less critical as central administration tolerates higher osmolality 3
- No evidence of osmotic demyelination syndrome has been reported even with much higher osmolality solutions when administered appropriately 3, 4