For more than 70 years, innovations in the complex oral drug product industry – from the early developments in immediate release medicines to functional ready-to-fill capsules – have formed the foundation of modern medicine in a variety of applications. A catalyst for these changes has come in the form of functional polymers and their ability to control the drug’s release profile. 

Controlled drug delivery occurs when a polymer is combined with a drug or other active agent to release the active agent from the material in a predesigned manner. This release can be constant over a long period of time or be triggered by its environment. Regardless of its timings, the intent behind controlling the drug delivery is to achieve a safe and effective therapeutic response while eliminating the risk of both under- and overdosing a patient.  

Much like with any medicine, controlled delivery systems have their benefits and setbacks. With this approach, health practitioners can maintain drug levels within a desired range and fully optimize the drug in question. However, obstacles include the possibility of high levels of toxicity or non-biocompatibility of the materials used in the drug product. 

This is why developing a drug with targeted release timings can mean the difference between success and failure in terms of effectiveness. In recent years, polymers designed primarily for medical applications have been deliberately designed to degrade within the body at different release points. Here we look at the different types. 

Most commonly found in over-the-counter pharmacies, immediate release tablets disintegrate rapidly and released all at once into the body. For this to be successful, the drug needs to be easily swallowable in the form of a tablet, capsule or other dosage form, as it can affect the rates of patient safety and compliance for future oral medications. Despite the quick nature of immediate release tablets, swallowability issues caused by disorders like dysphagia mean that pharmaceutical companies are encouraged to develop oral drug products for immediate release in dosage forms that are easy to swallow. To further enhance patient compliance with immediate release tablets (specifically in infants and children), a neutral smell and taste is highly desirable.  

Unlike immediate release tablets, an enteric coating (in forms such as tablets, capsules and multiparticulates) is used to ensure the medicine is released at later part inside the patient's body. The coating is pH activated and can only be dissolved at a higher pH level, which enables them to remain intact in the gastric environment and release the drug in the small intestine. The main benefit of this is that it prevents the risk of gastric mucosa irritation that can be caused by certain drugs or the “deactivation” of the drug by gastric fluids and delivers successful intestinal or colonic delivery of the active pharmaceutical ingredient (API). 

Extended release medicines are usually taken once daily as they are designed to keep the desired dosage levels at steady levels over a longer period. Sustained release products gradually circulate the API in a patient. However, they provide high levels of versatility in that the release can be customized with precise control due to the coating of multiparticulates or embedding the drug inside a polymer matrix. Sustained release coating polymers can be combined into single or multiple layers, which creates the unique opportunity to design customized profiles for sustained release that provide a constant level of medication within the body and improve the overall patient experience.  

One of the main issues with certain drugs is solubility, which is associated with poor permeability in the body. This can be affected by a variety of factors, such as molecular weight, particle size and dissolution from the oral solid dosage form.  

With new solubility enhancement technologies becoming available, manufacturers can resolve poor API stability in the gastrointestinal tract and increase bioavailability.  

At Evonik, we have established our reputation as a global leader in targeted functional polymer development with our EUDRAGIT® portfolio. With the flexibility to choose preferred process technologies for standard coating applications, multiparticulates, matrix tablets and other dosage forms, poly(meth)acrylate chemistry can be adapted for different release types.

Providing unrivalled versatility in pharmaceutical manufacturing, EUDRAGIT® polymers are available as aqueous dispersions, granules, organic solutions, or standard or pre-mixed powders for easy handling, and are compatible with all common process technologies.  

To showcase the benefits of our sustained release drugs, we were asked to formulate a multiparticulate concept using our EUDRAGIT® pellet technology for the treatment of schizophrenia. With a complex manufacturing process and patient wellbeing to consider, the concept required easy dosing in different dosage strengths.  

Compared to its nearest competitor, the EUDRAGIT® based multiparticulate sustained released formulation provided similar dissolution results from a wide range of pH values. In addition, the coating quality of the functional pellets led to improved solubility and permeability in the patient. 

With modern medicine continuing to evolve, pharmaceutical manufacturing has never been more advanced and while processes have changed along the way, the most important factor of keeping the patient comfortable and safe has remained a constant in the development of new medicine.  

Immediate, pH-triggered and time-controlled release drugs made with EUDRAGIT® as a baseline benefit all involved – from the manufacturer developing the latest oral drug product to the health professionals and patients, everyone can have the confidence in the treatment they receive.