Rohm and Haas creates new in vivo-like dissolution testing

Specialty chemicals maker Rohm and Haas has designed new equipments for its drug dissolution testing that it claims can reliably predict the release of oral drugs in vivo, and therefore potentially reduce the amount of animal testing.

When developing a new drug, it is important to demonstrate that the in vitro dissolution tests are predictive of the behaviour of the formulation in vivo - a process known as in vitro- in vivo correlation or IVIVC.

The firm claims its two new improved methodologies for buccal and gastrointestinal (GI) dissolution give an excellent level A IVIVC for oral dosage forms.

"Easy to use, they need no mathematical model and results can be interpreted quickly and effectively at the bench," the company said.

According to the firm, the new pieces of equipment - which were presented at CPhI in Paris - can handle a variety of oral dosage forms of the same drug including tablets, fast melts, capsules and syrups.

The effectiveness of oral dosage forms relies on the drug dissolving in the fluids of the gastrointestinal tract - or, for buccal dissolution, the mouth - prior to absorption into the system.

Drug dissolution - the rate of release of a finished drug product - is therefore becoming an increasingly important aspect in the development, particularly with the introduction of controlled-release dosage forms and the increasing use of low water-soluble drugs.

Rohm and Haas claims that its GI dissolution testing can allow it to determine how quickly tablets dissolve and enter the body, in a more comprehensive way compared to standard tests, because it analyses disintegration, dissolution, absorption and clearance under bio-relevant conditions.

One of the reasons for this is the methodology's aptitude to recreate the conditions of the human body environment.

In particular, the pH and composition in the cells can be changed during a test, which allows the effects of pH changes in the intestinal tract to be incorporated.

According to the company, this particular dissolution testing method is predictive of the "in vivo" availability - the amount of drug available to the body across different dosage forms of the same drug.

In addition, the firm offers similar equipment for the buccal dissolution testing to measure the efficiency of excipients used for taste masking.

For buccal dissolution the volume of saliva is very small compared to that of the stomach, but complete dissolution is not required.

It is therefore critical to remove finely divided solids from the test vessel to obtain a bio-relevant test.

The new method characterises the amount of drug that dissolves during its passage through the mouth.

It allows to predict the intensity of the taste of a dosage form relative to another dosage form or of a performance target. Also, it is rapid, as only 20 minutes are needed per test and it is repeatable, the company claims.

"Both dissolution tests have the potential to reduce the amount of animal testing, development time and cost," the firm said.