Theoretische Untersuchungen zur Adsorption von Arzneistoffen an Mikrokristalliner Cellulose (English shop)

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Microcrystalline cellulose (MCC) is a special processed form of native cellulose and is used in many areas of pharmaceutical technology. Among other things, it is employed as an excipient in wet granulation, where it comes into contact with active pharmaceutical ingredients.

In this work, computer-aided methods that allow the quantification of interactions were used in an attempt to investigate interactions of drugs with MCC at the molecular level. To this end, owing to the lack of a crystal structure of cellulose, a model based on coordinates for the cellulose Iβ polymorph first had to be created, representing the faces relevant for a microfibril within a single model while at the same time containing an amorphous subregion. The model created served as the basis for molecular dynamics investigations of the behaviour of MCC in aqueous and isopropanolic environments.

Using the drugs procaine hydrochloride and ethacridine lactate together with water, adsorption and interaction on this model were investigated by means of Monte Carlo simulation in combination with a simulated annealing procedure. To verify the quality of the method, pure water adsorption was carried out beforehand, the results of which were in agreement with experimental values.

The model presented in this work offers a sensible solution for being able to investigate all relevant faces in addition to an amorphous fraction within a single model. The procedure applied for the adsorption of drugs represents an efficient means of locating the most favourable adsorption sites with high probability.