What is sustain release tablet? Which Molecules are not suitable candidate for sustain release preparation?

Sustained-release tablets, also known as extended-release tablets, are designed to release the medication slowly over an extended period, typically over several hours or even days. This gradual release of the active ingredient helps to maintain therapeutic levels of the drug in the body, resulting in a more consistent and prolonged effect.

There are several factors to consider when selecting molecules for sustained release preparation, and not all molecules are suitable for this purpose. Here are some factors that may make a molecule unsuitable for sustained release preparation:

Small molecules: Small molecules can be difficult to formulate for sustained release, as they may diffuse too quickly out of the delivery system.

Highly water-soluble molecules: Highly water-soluble molecules can dissolve too quickly in the release medium and may be difficult to sustain the release of.

 

Highly lipophilic molecules: Highly lipophilic molecules tend to accumulate in the delivery system, which can result in a burst release.

 

Molecules with a short half-life: Molecules with a short half-life may be difficult to sustain release as they may degrade too quickly.

Molecules with high clearance rates:

Molecules with high clearance rates can be difficult to sustain release as they may be rapidly eliminated from the body.

Molecules with narrow therapeutic windows: Molecules with narrow therapeutic windows can be challenging to sustain release as maintaining a constant concentration within the therapeutic range can be difficult.

Molecules that are unstable or reactive: Molecules that are unstable or reactive can degrade or react within the delivery system, leading to a burst release.

 

Molecules that require a specific environment: Molecules that require a specific environment, such as a certain pH or temperature, may be difficult to sustain release in a different environment.

 

In summary, molecules that are small, highly water-soluble, or lipophilic, have a short half-life, high clearance rates, narrow therapeutic windows, are unstable or reactive or require a specific environment may not be suitable candidates for sustained release preparation.