Drug delivery gets sophisticated

New drug delivery solutions can improve treatment absorption rates and provide protection of pharmaceuticals against biochemical degradation within the body. (Image: stock.xchng)

For many years pharmaceuticals have consisted of simple, fast-acting formulations that are dispensed orally as solid tablets, capsules or liquids. But this is no longer the case.

A team of researchers from the Department of Pharmacy and Pharmacology at Wits University have developed new biocompatible and biodegradable drug delivery technologies, which can improve the efficacy of drugs used to treat diseases and conditions such as cancer, tuberculosis, HIV, epilepsy and other neurodegenerative disorders.

"Gone are the days where a tablet was just a white solid round structure," says Prof Viness Pillay, head of Pharmaceutics and Pharmaceutical Research at Wits University.

A drug delivery system controls or regulates the way in which a drug is released, absorbed, distributed, metabolised and eliminated by the body. If scientists find ways to control these parameters, drugs can function more effectively in the body.

Necessary for South Africa

Pillay says that research into new drug delivery systems has major benefits for South Africa, which already has a high burden of diseases that affect its economically-active population.

"If effective modes of treatment are not sought, this will lead to far reaching and detrimental socio-economic consequences," he says.

He adds that most local companies are not actively designing new drug delivery formulations or reformulating current products. Instead, their focus has shifted to generic formulations.

"Our innovative research in this field will assist the local pharmaceutical industry in acquiring and commercialising newer drug delivery technologies that will benefit them and the country," he says.

Having such pharmaceuticals developed locally and commercialised will also reduce South Africa's dependency on imported medicines.

Improved drug delivery

The goal of sophisticated drug delivery technology is to administer medicines to specifically targeted parts of the body, through a medium that can control the therapy's administration.

This can be done by means of either a physiological or chemical trigger.

"Our research has enabled us to understand how to control the rate of drug delivery, sustain the duration of therapy and manoeuvre the drug to target a specific organ or tissue while maintaining specific blood concentrations," he says.

The research team has also determined how they can utilise drug delivery routes such as the eye, nose, mouth, skin, gastrointestinal tract or vaginal mucosa, to deliver drugs to specific areas of the body.

Nano-neuropharmaceutics, wafers, chronotherapeutics and gastroretention are some of the technologies that the research team has been working on.

Nano-neuropharmaceutics

Nano-neuropharmaceutics are small brain implants to treat patients with neuro-degenerative disorders such as Parkinson's, Alzheimer's and Motor Neuron Disease.

The implant can be stimulated electronically or through the use of ultrasound to release the drug.

Wafers

Wafers that dissolve on contact with the mucosa in the cheek, allow patients to absorb a drug almost instantly.

He says that wafer technology is particularly useful for children and older patients who cannot ingest liquids, tablets and capsules.

For instance, there are currently no HIV drugs available to treat infected babies and young children. The current practice is to crush an adult tablet and mix it with milk.

However, he says that antiretroviral drugs are highly unstable in liquids and if babies don't finish their milk, they don't receive the prescribed dose.

"By making use of our wafer technology, the drugs are absorbed within eight seconds," he says.

Chronotherapeutics

Chronotherapeutics can treat diseases or conditions that only show signs and symptoms at certain times of the day. These include hypertension, rheumatic arthritis and heart attacks.

Chronotherapeutics release a specific amount of a drug at certain times throughout the day. The drug is released over a period of two hours after which it stops temporarily. The cycle is repeated later in the day or evening.

Gastroretentive delivery

The benefit of gastroretentive delivery is that the drug is retained within the stomach and then slowly released and filtered through the pyloric sphincter into the duodenum.

The pyloric sphincter is a strong ring of smooth muscle at the end of the pyloric canal which lets food pass from the stomach to the duodenum, the first part of the small intestine.

"Because the drug is filtered in such small quantities, it passes through the region at a very slow pace, which means the drug can be absorbed much more efficiently," says Pillay.

These technologies can improve treatment absorption rates and provide protection of pharmaceuticals against biochemical degradation within the body.

The majority of the new delivery methods have already undergone significant testing and those in the more advanced stages of research have entered the commercialisation process.

Reducing costs

The new drug delivery systems on offer will also result in a considerable overall reduction in the cost of medicine for patients, companies and the country.

"Cost in this instance does not mean only the physical rands and cents that companies or patients will be saving," he says. "Not providing effective treatment for a multitude of diseases can also be costly in terms of the socio-economic impact it will have if large numbers of the population are debilitated because of their disease, or are dying."

Developing new ways to administer medication that use less of the active pharmaceutical ingredient will also reduce the overall costs of medicine.