Abstract

Production of Water for Injection by non-distillation Methods / Operating Costs for hot or cold produced WFI

From the author’s point of view, unfortunately, operating costs for pharmaceutical water and steam have been playing a minor role for decades, or no role at all, in the majority of the producing pharmaceutical companies. Of course, patient safety must be paramount, and as part of the qualification process, risk analysis is the first step in lifecycle management. This, however, does not prevent us in any way from assessing operating costs in a sustainable way – and thus from saving energy and water to a really relevant extent. At this point, federal funding may be a particularly interesting aspect [Weiterführende Literatur / Fördermittel]. The reason for this situation can only be the overvaluation of the investment sum – in combination with uncertainties as to how quickly higher investment costs will pay off. Another cause may be the mistaken assumption that in terms of technology, manufacturers are similarly positioned. Suppliers must be contractually bound to assume their responsibilities with regard to the consumption values they guarantee. The revised monograph “Water for Injection (0169)” – Ph. Eur. Supplement 9.1 and the new Annex 1 Draft allow the production of WFI without distillation, according to the provisional EMA Directive “Questions and answers on production of water for injections by non-distillation methods – reverse osmosis and biofilms and control strategies” [1].

The “cleaning process”, i.e. reverse osmosis in connection with the use of suitable technology, should be demonstrably equivalent to or better than distillation [1]. With this, the road is open for the production of WFI using the membrane process – with the appropriate safety – at reduced operating costs as well as low energy and water consumption. Business economists will certainly be happy, because this also results in reduced investment costs, since instead of two processing plants (reverse osmosis and distillation), whose acquisition would be similarly expensive, only one plant (reverse osmosis) is required, the cost of which will be higher by only 30–50 %. Furthermore, only one tank and one loop are necessary. At the same time, energy costs will be considerably reduced, since the energy-consuming phase-change from liquid to vapor state is no longer required. Given the fact that in this case, cold produced WFI is mostly stored in cold conditions, further energy savings may result, as hot WFI often requires cooling prior to its use. As in this case, there is only one water quality to be managed, also monitoring costs, which sometimes may be considerable, can be reduced by about 40 %.