What is the zero-order model?

Zero-order release assumes a constant release rate regardless of drug concentration: Q(t) = K0 * t. It applies to reservoir systems with a rate-controlling membrane.

When should I use the Higuchi model?

The Higuchi model (Q = Kh * sqrt(t)) describes diffusion-controlled release from a homogeneous matrix where the initial drug loading exceeds its solubility. It is the most widely used model for matrix tablets and polymer films.

What does the Korsmeyer-Peppas n exponent mean?

The release exponent n describes the transport mechanism: n = 0.89 indicates case-II transport (swelling/erosion controlled). Values up to 1.0 are common for cylindrical or spherical geometries with different thresholds.

How do I get the rate constants for my formulation?

Rate constants are derived by fitting the appropriate model equation to experimental cumulative release data (e.g., dissolution or elution assay measurements). Statistical software or simple linearization (e.g., Q vs. t for zero-order, ln(1-Q/Q0) vs. t for first-order) can be used.

Can cumulative release exceed 100%?

In a real formulation it cannot. This calculator caps cumulative release at 100% of the initial drug load. If your inputs predict values above 100% early, your rate constant may be too high for the specified drug load, or you may need a shorter time window.

How do I calculate cumulative drug release?

Cumulative drug release is the running total of drug released up to a time point, expressed as a percentage of the initial load: Q(t) / Q0 x 100. Pick the kinetic model that fits your data (zero-order, first-order, Higuchi, or Korsmeyer-Peppas), enter its rate constant, and the calculator returns cumulative release in both percent and absolute mass at any time.

Drug Elution Rate Calculator

Model drug release from polymer matrices or drug-eluting implants using zero-order, first-order, Higuchi, and Korsmeyer-Peppas kinetic models.

Parameters

Initial Drug Load (Q₀, µg)

Plot Duration (hours)

Model Rate Constants

Zero-Order Q = K₀·t

K₀ (µg/h)

First-Order Q = Q₀(1−e^−K₁t)

K₁ (h⁻¹)

Higuchi Q = K_H·√t

K_H (µg/h^0.5)

Korsmeyer-Peppas Q/Q₀ = K_KP·tⁿ

K_KP (h⁻ⁿ)

n (exponent)

Query Time Point (hours)

Cumulative Release vs. Time

Results at t = 24 h

Model	Released (µg)	Released (%)	Rate (µg/h)
Click Calculate to see results

Summary

Calculate cumulative drug release and release rate at any time point using four standard pharmaceutical kinetic models: zero-order, first-order, Higuchi matrix diffusion, and Korsmeyer-Peppas power law. Useful for drug-eluting stents, biodegradable implants, and controlled-release polymer coatings.

How it works

Enter the initial drug load (Q0, µg) and the plot duration in hours.
Set the rate constant for each kinetic model you want to compare (zero-order, first-order, Higuchi, Korsmeyer-Peppas).
Choose a query time point to read cumulative release at that exact moment.
Click Calculate — the tool computes cumulative release (% and µg) and the instantaneous release rate for each model.
Compare release profiles on the time-course chart and check the T50 and T80 milestones.

Use cases

Compare predicted release profiles from drug-eluting stent coatings.
Estimate drug remaining in a biodegradable PLGA implant at a given time.
Fit experimental release data to an appropriate kinetic model.
Determine the time to 50% or 80% cumulative release for formulation screening.
Evaluate Fickian vs. anomalous transport using the Korsmeyer-Peppas n exponent.

Frequently Asked Questions

Last updated: 2026-09-30 · Reviewed by Nham Vu