Calculate an ICH Q3C(R9) permitted daily exposure from a qualified toxicology point of departure and modifying factors.

ICH Permitted Daily Exposure Calculator

Calculate an ICH Q3C(R9) PDE from a professionally selected toxicology point of departure and modifying factors. The equation uses ICH’s fixed 50 kg adult body-weight basis.

Use the value and units documented in the source toxicology assessment.

ICH Q3C fixes F2 at 10.

Requires toxicologist judgment based on the severity of toxicity.

Use 1 with a suitable NOEL; if only a LOEL is available, ICH permits a factor up to 10 based on severity.

If supplied, the calculator also reports the Option 2 concentration in ppm.

ICH Q3C(R9) PDE Formula

The ICH residual-solvent equation is PDE = NOEL × 50 kg / (F1 × F2 × F3 × F4 × F5). The 50 kg body-weight term is the convention specified by ICH for an adult; this calculator does not substitute a user-entered weight. F1 accounts for species, F2 is fixed at 10 for individual variability, F3 accounts for study duration, F4 addresses severe toxicity, and F5 is used when an adequate no-observed-effect level is unavailable.

When a daily product mass is supplied, the Option 2 concentration is ppm = 1000 × PDE (mg/day) / daily product mass (g/day). This conversion does not replace the separate ICH rules for Option 1 limits, multiple residual solvents, or justified higher levels.

Professional Scope and Safety Limits

F3, F4, and F5 are not generic consumer settings. Their selection depends on the study design, duration, endpoint severity, and whether the point of departure is a NOEL or LOEL. Source values must be reviewed in their toxicological context by appropriately qualified professionals. Q3C(R9) covers residual solvents in pharmaceuticals; it is not a general-purpose occupational, environmental, pediatric, or patient-specific dose calculator.

Primary reference: ICH Q3C(R9), Impurities: Guideline for Residual Solvents.