BCC Research classifies USP water as a general chemical in its analysis of the global excipient market. USP water includes water for injection (WFI) and purified water. Water must comply with USP standards for chemical purity and microbial content (i.e., < 0.25 ppm of endotoxins). WFI accounts for 76.5% of the USP water market, or $52 million, and purified water 23.5%, or $16 million (1).
Pharmaceutical grades of water used in drug-process applications (i.e., enema and medical-irrigating fluids) and other than
those used to formulate excipients are excluded from the analysis. Also excluded is water used as: a pharmaceutical manufacturing
process aid (i.e., wet granulation); a solvent for aqueous-based, film-coating materials; a cleaning and rinsing material for containers
and closures; a fermentation or cell-culture media ingredient; an extraction and purification solvent; a chemical-reaction
solvent; or any other purpose except in a formulated drug-dosage form.
Excipients serve various functions within a pharmaceutical formulation. Table II breaks down the global excipient market by
functional type on a value and volume basis. An ongoing goal of excipient development is to achieve multifunctionality with
a single or a reduced number of excipients in a formulation. Despite increased interest by pharmaceutical companies to add
functionality, excipient producers say it is difficult to bring new excipients to market.
Table II: Global excipients market by functional type (1).
"As there is not an approval process for excipients, the introduction of new materials for use as excipients takes a very
long time, and most suppliers are not willing to invest as the rewards do not justify the investment for a material new to
the industry," explains Tim Bee, senior director of the global pharmaceuticals business at International Specialty Products (ISP, Wayne, NJ).
"The cost of new excipients in terms of the need for toxicology studies is prohibitive for most excipient companies," adds
Alen Guy, vice-president of research and development at JRS Pharma (Patterson, NY). "The return on investment is not there, and such a venture needs a 'slam dunk' application to receive senior-level
Although introducing new excipients is a slow and costly process, the excipient market is not without innovation. Excipient
makers use a strategy of developing excipient blends to achieve multifunctionality and introduce new grades of existing excipients
to enhance performance for specified applications. Excipients for orally disintegrating tablets (ODTs) and controlled-release
formulations are recent examples.
Orally disintegrating tablets.
In September 2007, BASF launched "Ludiflash," a coprocessed excipient consisting of three ingredients: a special grade of
mannitol used as a filler; crospovidone used as a superdisintegrant; and a polyvinyl acetate dispersion used as a binder.
Ludiflash was specifically developed for the manufacture of ODTs but can also be used as granules or powder in sachets. Because
it contains a filler, binder, and disintegrant, only the API and a lubricant are added to the formulation. Colorants and taste-masking
agents may also be used.
"Ludiflash offers properties not achievable by simply blending the three ingredients," explains Dr. Ralf Widmaier, marketing
manager at BASF SE (Ludwigshafen, Germany). "It offers a wide-processing window and very good hardness and low friability of the tablets at
disintegration times within 10–30 s in the mouth without drinking water."