In pharmacology, how are controlled release and sustained release dosing typically defined?

Controlled release (CR) and sustained release (SR) formulations are designed to release a drug at a predetermined rate, allowing for a prolonged therapeutic effect. Typically, CR formulations are designed to be taken once daily, which helps maintain a stable drug concentration in the bloodstream over an extended period. This is particularly beneficial for medications that require consistent therapeutic levels, as it improves patient adherence and reduces the fluctuation of drug levels.

On the other hand, sustained release formulations may allow for dosing more than once a day, but they are often designed to extend the duration of action compared to immediate release formulations, which can lead to variability in dosing schedules depending on the specific medication and its intended use.

The information in the correct answer aligns with the common understanding in pharmacology regarding these dosage forms. Controlled release is succinctly characterized by the once-daily dosing schedule, while sustained release can vary but often aims to provide a smoother release compared to regular formulations. Thus, answer B accurately represents the typical definitions of controlled versus sustained release dosing.