Dissolution
The effectiveness of tablets or capsules administered orally relies on the drug dissolving in the fluids of the gastrointestinal tract prior to absorption into the systemic circulation. It is widely acknowledged that the rate at which the drug dissolves is critical to its therapeutic efficacy and as such, is considered a Critical Quality Attribute (CQA) in both the formulation process and final quality control. Determining bioavailability via in vivo drug release analysis studies (e.g. urine or plasma analysis) can be impractical, particularly when such techniques are required on a routine basis. To overcome such issues, official in vitro dissolution tests have been rigorously and comprehensively defined in the respective Pharmacopoeias and are essential for: • Predicting in vivo drug bioavailability • Assessing bioequivalence and its application in scale-up and post-approval changes • Optimising therapeutic effectiveness during development and stability assessment • Ensuring uniformity between production lots
A
B
Dissolution Vessel
9.4 to 10.1
Stiring Element
B
A
42.11
Stiring Element
Vessel with stiring element designed to simulate conditions within the gastrointestinal tract
A
B
Dissolution methods aim to provide important in vitro drug release information for both drug development and quality control purposes.
Initially developed for oral dosage forms, the role of the ‘dissolution test’ has now been expanded to the ‘drug release’ of various other forms such as semisolids topical and transdermal systems (see page 74).
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