Continuous dissolution rate determination as a function of the pH of the medium.
A method was developed for varying the pH of the medium during dissolution rate studies of timed-release tablets with the aid of compressed, totally soluble, alkaline powder mixtures. Commercial as well as experimental timed-release capsules or tablets were used as models, and dissolution rates were determined at pH 1.1, 2.4, and 7.4. The system can be applied to other pH values or other variations of the dissolution medium (e.g., ionic strength) to: (a) correlate in vitro release rates with bioavailability data, (b) discriminate between alternative formulations during dosage form development, or (c) serve as a selective control procedure for a series of sustanined-release dosage forms.
Continuous dissolution rate determination as a function of the pH of the medium. A method was developed for varying the pH of the medium during dissolution rate studies of timed-release tablets with the aid of compressed, totally soluble, alkaline powder mixtures. Commercial as well as experimental timed-release capsules or tablets were used as models, and dissolution rates were determined at pH 1.1, 2.4, and 7.4. The system can be applied to other pH values or other variations of the dissolution medium (e.g., ionic strength) to: (a) correlate in vitro release rates with bioavailability data, (b) discriminate between alternative formulations during dosage form development, or (c) serve as a selective control procedure for a series of sustanined-release dosage forms.