Oral controlled- release formulation
1.A film coating is a process of coating a polymer (e.g. Opadry) to the surface of a tablet to improve the stability and modify the drug release effects.
2.Immediate release film coating: This technology creates distinctive tablet appearance to differentiate product characteristics, the ability to swallow, masking odors, and improving tastes. Film coating may improve the physical property, color, gloss, and even the pearlescence of the immediate release film-coated tablets, and it also can prevent damp and increase patients' compliances, e.g. Acetaminophen.
3.Sustained release film coating. These delivery systems are formed by a high molecule weight polymer, e.g. ethylcellulose. It usually can be classified as the aqueous dispersion (surelease) or an organic solvent based ethylcellulose, and further achieve its drug releasing effects from the controlled-release tablets.
4.Enteric release coating: The enteric coating is applied to control drug release in various gastrointestinal pH, and it also can be classified as the aqueous- and organic solvent-based polymer, e.g. Eudragit? L30-D55 or Acryl-EZE?. There are different coating systems can be selected for protections of enteric releasing.
5.For the solid dosage forms, the film-coating technique can improve packing efficiency, prevent cross-contamination, and reduce the damages during transportation. It can be added into various pigments to provide identity. At the same time, it can protect the products from light, damp and moisture.
《Oral sustained-release/Controlled-release formulation》
1. Sustained-Release formulation
A drug dosage is released in a designated matrix at a predetermined slow rate but not at a constant rate.
A drug dosage is released in a designated medium at a slow and constant or near-constant rate.
【The development of sustained- and controlled-release technology】
1.Constant release: a formulation is released in vivo at a fixed (zero order) rate in order to reduce the fluctuation of drug concentration in blood and increase patients’ compliances.
2.Site-controlled release: a formulation that can enhance the effectiveness of local treatment or increase the drug absorption at the specific sites.
3.Time-controlled release: a formulation that can release suitable amount of drug depending on biological rhythm to obtain the best effectiveness of treatment.
1.A small fluctuation of drug concentration in plasma of users.
2.It maintains a slow and steady release rate of the drug even in large intestine with very low water content.
3.The drug absorption does not affect by the gastrointestinal pH.
4.The drug absorption will not affect by food.
5.The drug will have a slight gastrointestinal irritation.
《Two-stage oral controlled-release formulation》
【Mixed film-coating controlled release formulation】
Product contains two different rate mechanisms of controlled-release for maintaining a stable drug concentration in blood for drug effectiveness.
1.Technology of particle design: Upon treating a chronic disease, drug concentration in blood shall be maintained at a stable level for a period of time. The drug product will have an initial dose (rapidly reach a certain concentration in blood) and a maintaining dose (maintain a certain concentration in blood). These multi-stage controlled-release formulations can be applied for such cases and maintain the effectiveness of the drug.
2.Formulation technology of dosage forms: The current technology is applied to the development of medications for patients with hypertension and diseases of central nervous system.