Disintegrating pellets from a water-insoluble pectin derivative produced by extrusion/spheronisation

Pectinic acid (PA) and microcrystalline cellulose (MCC) as extrusion aiding excipients have been compared. Three different drugs were selected as models: Riboflavin with a very low water solubility, paracetamol and theophylline as drugs with high water-solubility. The drug load was varied from 1 to 80% wt. The low-soluble pectin derivative, PA (degree of methoxylation <10%) was found to be well suited as an extrusion aiding excipient in pellet preparation by extrusion/spheronisation. The substance has a high drug loading capacity and produces disintegrating pellets that are well suited for fast delivery of drugs with a low water-solubility. The pellets are also mechanically stable. Compared to MCC, PA was found to require less water for pellet formation and was more sensitive against changes in the water content. In order to achieve optimal shape of the pellets, spheronisation was carried out at 45 degrees C. PA is more sensitive to type and amount of drug and is, consequently, not as universally applicable as the conventionally used microcrystalline cellulose. The great advantage of pectinic acid is, however, the disintegrating properties of the pellets after only a short time of exposure to liquid.