From the Guidelines
Delayed release and extended release formulations have distinct differences in their drug delivery mechanisms, with delayed release protecting the drug from stomach acid and releasing it after a time delay, and extended release gradually releasing the medication over time to maintain therapeutic levels. The primary distinction between these two formulations lies in their release patterns, as evidenced by the characteristics of available 5-aminosalicylates (5-ASA) and sulfasalazine 1. Delayed release formulations, such as enteric-coated tablets (e.g., Asacol), are designed to release the active ingredient in the distal ileum and colon, bypassing the stomach. In contrast, extended release formulations, like controlled release formulations (e.g., Pentasa) or MMX formulations (e.g., Lialda), deliver the medication over an extended period, starting from the duodenum and continuing into the lower bowel. Some key points to consider include:
- Delayed release formulations are often used to reduce gastrointestinal side effects by releasing the medication beyond the stomach
- Extended release formulations aim to provide consistent therapeutic levels, reducing the need for frequent dosing and minimizing peak-related side effects
- The choice between delayed and extended release formulations depends on the specific medication, the condition being treated, and patient factors, such as adherence and side effect profiles, as noted in the management of mild-to-moderate ulcerative colitis 1. In terms of therapeutic effect, extended release formulations tend to provide more consistent blood levels and smoother symptom control, whereas delayed release formulations focus on protecting the drug from degradation or reducing specific adverse effects. This is particularly relevant in the context of medications like mesalamine, where the delivery mechanism can impact the efficacy and tolerability of the treatment 1.
From the FDA Drug Label
Following a single oral dose of metformin hydrochloride extended-release tablets, C max is achieved with a median value of 7 hours and a range of 4 to 8 hours Peak plasma levels are approximately 20% lower compared to the same dose of metformin hydrochloride tablets, however, the extent of absorption (as measured by AUC) is comparable to metformin hydrochloride tablets.
The main difference between delayed release and extended release (ER) formulations is the way the active ingredient is released into the body.
- Delayed release formulations are designed to release the active ingredient after a certain delay, allowing the drug to reach a specific part of the body before being released.
- Extended release (ER) formulations, on the other hand, release the active ingredient over an extended period, providing a longer duration of action. In terms of therapeutic effect, the extended release formulation of metformin provides a similar extent of absorption compared to the immediate release formulation, but with a slower peak plasma concentration, which may help to reduce gastrointestinal side effects. Key points to consider:
- The extended release formulation may provide a more stable and sustained release of the active ingredient, which can lead to improved therapeutic outcomes.
- The delayed release formulation may be more suitable for certain conditions where a delayed release is beneficial. It is essential to consult the FDA drug label and medical professionals for specific guidance on the use of these formulations, as the choice between delayed and extended release depends on individual patient needs and medical conditions 2 2.
From the Research
Delayed Release vs Extended Release Formulations
The main difference between delayed release and extended release (ER) formulations lies in their drug release profiles.
- Delayed release formulations release the drug after a certain time lag, whereas
- Extended release formulations release the drug over an extended period, providing a sustained therapeutic effect 3.
Therapeutic Effects
Extended release formulations are designed to provide a consistent and sustained release of the drug, resulting in:
- Reduced peak blood levels and associated adverse effects
- Improved patient compliance due to less frequent dosing
- More uniform plasma drug profiles 4, 5. In contrast, delayed release formulations may not provide the same level of sustained release, but can still offer advantages such as reduced local adverse effects in the gastrointestinal tract 3.
Specific Applications
Extended release formulations have been successfully used in various therapeutic areas, including:
- Neuropsychiatry, where they can reduce adverse effects and improve compliance 3
- Hypertension, where they can provide continuous 24-hour control of blood pressure 4
- Chronic pain management, where they can offer convenience, reduced pill burden, and attenuated peaks and troughs in serum concentration 5
- Attention-deficit/hyperactivity disorder (ADHD), where they can provide improved safety, tolerability, and convenience 6.
Manufacturing Processes
Extended release formulations can be manufactured using various techniques, including hot melt extrusion (HME) and 3D printing, which offer advantages such as improved product quality and reproducibility 7.