Providing less invasive drug delivery with biopolymers

Evonik is currently working on a German Federal Ministry-funded project to find oral delivery solutions for injectable biopharmaceuticals. One route to producing less invasive therapeutic options involves using next-generation biopolymers

Production of parenteral medications requires the highest hygienic standards. Shown here is the site in Birmingham (Alabama, US)

It is a given that medications should work. But they can do so only if the active reaches its targeted location in the body and remains in place long enough and at a high enough concentration. Evonik says biodegradable polylactides (polylactic acids) and their copolymers, which the company markets under the brand names Resomer and Resomer Select, are especially suited to create sustained release formulations for modern drugs that are injected.

Although most medications are taken orally, e.g. as tablets or capsules, many modern protein or nucleic acid-based biotherapeutics, such as those used to combat cancer, diabetes or multiple sclerosis, must be administered by injection – under the skin (subcutaneously), into the muscles (intramuscular), or directly into the vein (intravenously).

Drug efficacy is often influenced by the formulation and sustained release formulations provide controlled release of drugs over a longer period. ‘We formulate modern biotherapeutics with our Resomer biopolymers and so enable gentle and effective treatment options,’ said Jean-Luc Herbeaux, Head of Evonik’s Health Care Business Line. The finished product is usually formulated as microparticles or as rod implants to be injected subcutaneously or intramuscularly – depending on the desired effect. The active ingredient is continuously released over a defined period as the body gradually degradates the polymer matrix.

Biodegradable polylactides (polylactic acids) and their copolymers are especially suited to create sustained release formulations for modern drugs that are injected

‘With the help of novel biopolymers, we hope it will be possible in the future to bring biopharmaceuticals into the bloodstream through the gastro-intestinal tract and through respiratory pathways rather than through injections,’ he added.

As part of PeTrA1, a project co-funded by the German Federal Ministry of Education and Research, Evonik has worked with partners to develop novel biocompatible and biodegradable lactic and glycolic acid-based copolymers (PLGAs) and test them in cell models.

The company says the advantages of biodegradable polylactic acids can be seen in patients who are suffering from a certain type of prostate cancer and treated with an LHRH antagonist. These drugs aim to stem the progress of hormone-dependent cancer by suppressing testosterone production. Since a constant drug level is required, the LHRH antagonist would actually need to be injected several times a day. Thanks to a polymer-based sustained release formulation that is injected under the skin in the shape of a small rod, injection is only necessary every six months thereby increasing comfort and compliance and reducing cost of treatment.

Boris Obermeier, who is responsible for developing biopolymers at Evonik, sees the use of nanoparticles as a step toward even more targeted drug delivery systems. ‘With customised polymers and suitable formulations, we can protect drugs from the attacks of the immune system, allow them to circulate longer in the blood stream and precisely accumulate in a particular tissue,’ he said at the Evonik Meets Science forum in Fulda, Germany.

Biodegradable polymers have also been used in medical device applications

Biodegradable polymers have also been used in medical device applications. A variety of medical devices can be produced from polylactic acids – from a simple screw or plate to stabilise a broken bone, to absorbable stents. The advantage of these applications is that the material is programmed to be metabolised by the body within months to years and a removal by a second surgery is not necessary.

Future opportunities for biodegradable polymers lie in the synthetic production of biological tissue to replace or regenerate diseased tissue in patients. Biological tissues need a stabilising matrix that the cells can grow on. A matrix made of biodegradable polymers present the advantage to be absorbed by the body later on. ‘All of these applications need well-tolerated materials whose properties can be adjusted to suit specific requirements,’ said Obermeier.

Evonik has its own development and production capacities for functional polymers in Darmstadt (Germany) and Birmingham (Alabama, US).

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