“Being at the right place at the right time"

Advanced drugs contain far more than just the active ingredient: Special auxiliary components transform tablets and capsules into intelligent transport systems. The aim is to ensure that as little as possible of the active substance is lost as the drug travels through the body. EUDRAGIT® pharmaceutical polymers enable active ingredients to be target delivered to the desired site of action in the body. These specialty polymers from Evonik release the active ingredient exactly where it is needed—and, moreover, at a precisely defined point in time or over a defined timespan.

Most drugs begin their journey through the body as tablets or capsules, for which the first stop is the stomach. To prevent active ingredients from being destroyed, and thus rendered ineffective, in the acid environment of the stomach, Evonik's polymer chemists came up with the idea, way back in the early 1950s, of producing film coatings for drugs that dissolve only at particular pH values. That marked the advent of EUDRAGIT® and the concept of drug targeting, or targeted release of active substances.

A lot of current drugs are high-tech products combining know-how from various scientific disciplines. Pharmacologists research exactly how an active ingredient is absorbed, metabolized, and excreted by the body. Using this information, pharmaceutical technicians develop the pharmaceutical form, which is the form—such as ointment or tablet—in which the drug can act most effectively. Until the 1950s, all drugs, including the most advanced, shared one critical drawback: It was not possible to precisely control the time and place of release of the active ingredients. EUDRAGIT® polymers changed all that. Ever since, polymers from Evonik Industries have allowed targeted active-ingredient release from oral pharmaceutical forms.

Management of drug action in the human body

An active ingredient can be absorbed ino the bloodstream and act optimally only if it reaches the right place without its integrity having been compromised along the way. The ultrathin tablet coating serves to protect the tablet during its journey through the digestive tract. "We can use pH to control active ingredient release," explains Dr. Tomas Riermeier, head of Innovation Management at Evonik's Pharma Polymers Business Line. "Because the environment of the stomach is more acidic than that of the small intestine, it is possible to tailor-make a coating that dissolves at the required pH values, either pH 1-5 in the stomach, above pH 5.5 in the small intestine, or above pH 7 in the large intestine." There are now three main groups of EUDRAGIT® polymers on the market worldwide: alkali-soluble types that are enteric (resistant to gastric juice) and release the active ingredient only in the intestine; acid soluble types for drugs that are to be released in the stomach; and EUDRAGIT® grades for sustained-release formulations, where the drug does not release the active ingredient in a single shot but continuously, over a defined timespan. Sustained-release forms are especially suitable for drugs such as painkillers or beta blockers, used to treat high blood pressure. Because many EUDRAGIT® grades combine very well with one another, they can be used to develop almost any desired release profile.

Protection against aggressive active ingredients

In addition to the location of release of the active ingredient, the duration of release is also important for the action of a drug in the body. Short acting active ingredients in particular must be released over a longer period, so that the patient ideally needs to take a tablet or capsule only once, rather than several times, a day.

The optimal release rate, which maintains a constant level of active ingredient in the body over several hours, can be achieved by a targeted combination of various EUDRAGIT®polymers.

For many drugs, a protective coating also serves other important purposes: It increases chemical, physical, and mechanical stability, protects against moisture, and masks the taste and smell of active ingredients. Children in particular will be cheered by the news that medicine need not taste awful to be good for you.

EUDRAGIT® is a registered trademark of Evonik Industries AG or its subsidiaries. It is presented in capital letters throughout this text.