OIA1008 DISSOLUTION

Sink condition

A situation where the volume of the dissolution medium is large enough to ensure that the drug concentration does not exceed 10–15% of its saturation solubility.

Dissolution

The process by which a solid substance dissolves in a solvent to form a solution; important for the bioavailability of oral drugs.

USP Apparatus 1 (Basket)

Used mainly for capsules; the dosage form is placed in a wire mesh basket that rotates in the dissolution medium.

USP Apparatus 2 (Paddle)

Commonly used for tablets; a paddle stirs the dissolution medium while the dosage form sits at the bottom of the vessel.

Dissolution medium

A liquid used in testing to simulate conditions in the gastrointestinal tract, often consisting of buffers like 0.1N HCl, phosphate buffer pH 6.8, or water.

Agitation speed

The speed at which the paddle or basket rotates; affects the rate of drug release from the dosage form.

Volume of dissolution medium

Typically 500–1000 mL; should be sufficient to maintain sink conditions and ensure proper drug release.

Temperature for dissolution test

Maintained at 37±0.5°C to simulate human body conditions.

Sample withdrawal

The process of removing aliquots from the dissolution vessel at predetermined times for analysis.

Apparatus calibration

Ensures the dissolution apparatus is functioning properly, often done with standard calibrator tablets.

Drug release profile

A graph showing the percentage of drug released over time; used to compare different formulations or batches.

Zero-order kinetics

Drug release at a constant rate, independent of concentration.

First-order kinetics

Drug release rate proportional to the concentration of drug remaining in the dosage form.

Higuchi model

Describes drug release from a matrix as a square root of time-dependent process based on Fickian diffusion.

Korsmeyer-Peppas model

Used when the release mechanism is not well understood or involves multiple phenomena.

Fick’s law

Describes the diffusion process where the drug moves from high to low concentration areas; foundational for several dissolution models.

Controlled-release formulations

Designed to release the drug over an extended period; dissolution testing helps predict in vivo performance.

Bioavailability

The rate and extent to which the active drug is absorbed and becomes available at the site of action.

Biowaiver

Regulatory acceptance to waive in vivo bioequivalence studies based on in vitro dissolution tests.

IVIVC (In Vitro-In Vivo Correlation)

A predictive mathematical model describing the relationship between an in vitro property and a relevant in vivo response.