Innovation in Excipients

Newly developed pharmaceutical excipients of isomalt, a polyol that has been widely used for more than 20 years as a bulk sweetener in sugar-free confectionery and nutraceutical products have been launched the brand name GalenIQ. Based on its physical, chemical and physiological properties, the new range of pharmaceutical excipients, brings together the advantages of well-known bulk excipients, facilitating drug development and formulation whilst meeting the high standards required by the pharmaceutical industry. Moreover, with physical and chemical modifications, the new isomalt excipients are tailor-made for pharmaceutical applications in the field of solid-dosage forms for oral delivery (1). The following article discusses the most important properties of isomalt excipients, and the tabletting characteristics of direct-compressible (DC) grades.

MANUFACTURE – NON-ANIMAL ORIGIN

The qualities of isomalt excipients are derived from sucrose in a two-stage production process (2). First, sucrose is converted in an enzymatic transglucosidation to the disaccharide 6-O-α-Dglucopyranosyl fructose (isomaltulose) – a significantly more stable reducing compound. Secondly, the hydrogenation of isomaltulose leads to the stereoisomer disaccharide alcohol 1- O-α-D-glucopyranosyl-D-mannitol dihydrate (1,1-GPM dihydrate) and 6-O-α-D-glucopyranosyl-D-sorbitol (1,6-GPS) in an approximate equimolecular mixture (see Figure 1).

Through an additional process, the ratio between the two molecular components can be varied. As a result, specific qualities are obtained – enriched in 6-O-α-D-glucopyranosyl- D-sorbitol (1,6-GPS), providing higher solubility (3). Depending on the composition, the qualities of the excipient contain approximately three to five per cent crystal water, which is strongly bound to the GPM crystal. In its final state, it is a white, odourless, water soluble, crystalline substance that complies with the isomalt monographs of the current Ph Eur, BP and USP29-NF24.

Through particle engineering, a wide product range can be developed that includes specific solid-dosage forms like tablets, pellets, capsules, granules, sugar-free coatings (3) and highboiled lozenges (7,8). Grades for applications such as wetgranulation, agglomeration (9), powder mixtures or melt extrusion processes, complete the range (10). As direct compression is the most frequently administered application form, two special grades have been developed to support formulators in the design of all kinds of tablets.

GENERAL PROPERTIES