Switzerland's Novartis has been awarded a US patent for a novel means of extending the shelf life of pharmaceuticals. The invention describes the use of a plastic bottle made from a polymeric material that is impregnated with an antioxidant.
The patent (No 6,576,649), awarded on 10 June, notes that there is a need to stabilise pharmaceutical compositions, and in particular aqueous pharmaceutical compositions such as aqueous eye drops, such that they are stable against decomposition caused by heat, light and/or oxygen exposure. The use of an antioxidant-laden bottle helps to solve this problem, with the added advantage that it may be possible to omit an additional antioxidant and/or a stabiliser from the pharmaceutical composition.
The description notes that polyethylene and polypropylene are the preferred polymers to use in the manufacture of the plastic container, while it makes specific reference to the use of Ciba Specialty Chemicals' Irganox 1330 antioxidant. Examples of pharmaceutical ingredients which could benefit from packaging in such a system include the antihistamine ketotifen and retinoic acid.
The description claims that such compositions "usually exhibit an enhanced tolerability as compared to ordinarily stabilised compositions, since the antioxidant is not administered to the organism."