Isotonicity Calculator
Sodium chloride equivalents (E-values) for ophthalmic/parenteral formulations
Formulation Ingredients
| Ingredient | Concentration | E-Value | Action |
|---|---|---|---|
Common Ingredients
E-value Formula
Σ(C × E) = 0.9%
C = concentration (% w/v)
E = NaCl equivalent
0.9% = isotonic NaCl
Why Isotonicity Matters
- • Prevents ocular discomfort and tissue damage
- • Essential for IV solutions (prevents hemolysis)
- • Affects drug absorption
- • Required by pharmacopoeias
Common E-values
Sodium Chloride1.00
Dextrose0.18
Boric Acid0.50
Glycerin0.34
Guidelines
Ophthalmic: 0.6–1.1% NaCl equiv
IV: 0.45–0.9% acceptable
IM: small volumes can be hypertonic
Neonatal: strict isotonicity