Interpretation of dissolution rate data from in vitro testing of compressed tablets

Area of Science:

• Pharmaceutical Sciences
• Physical Chemistry

Background:

• Dissolution rate is critical for drug bioavailability.
• Existing theories by Wagner (1969) and Kitazawa et al. (1975) offer different approaches to dissolution modeling.

Purpose of the Study:

• To investigate the theoretical and experimental relationship between Wagner's and Kitazawa's dissolution rate theories.
• To evaluate the applicability of these theories to uncoated pharmaceutical tablets.

Main Methods:

• Utilized two distinct dissolution methods for analysis.
• Tested uncoated tablets of caffeine, aspirin, and proxyphylline.
• Compared dissolution rate constants derived from both theoretical models.

Main Results:

• Dissolution rate constants obtained from both theories showed fair agreement.
• Despite differing treatments of surface area, the models yielded comparable results.
• The Kitazawa et al. plot proved a potentially useful and simple method for determining dissolution rate constants.

Conclusions:

• The study suggests that explicit consideration of surface area changes may not always be necessary when calculating dissolution rates.
• Kitazawa's graphical method offers a practical approach for determining dissolution rate constants from compressed tablets.