§ Mr. BurstowTo ask the Secretary of State for Defence if he will list the impurities produced when Pyridostigmine Bromide is(a) exposed to intense sunlight,(b) subjected to large temperature variations and (c) stored for long periods under these conditions.[40142]
§ Dr. ReidBetween 1987 and 1992, the Chemical and Biological Defence Sector of the Defence Evaluation and Research Agency conducted studies to assess the storage stability of the Ministry of Defence's Nerve Agent Pretreatment Set (NAPS) tablets, which contain pyridostigmine bromide (PB) as the active ingredient. The tablets were exposed to a range of temperatures between 5 and 41°C and storage times of up to 5 years.
The only significant detectable degradation product of PB identified during these studies was 3-hydroxy1-methyl pyridinium bromide, which is also the major metabolite produced when PB is taken orally. The other known degradation products of PB, which were not detected in any long term stability studies due to their 229W transitory nature, are 3-hydroxy pyridine and pyridy1- 3-dimethyl carbamate. Neither of these, nor 3-hydroxy1-methyl pyridinium bromide, are known to be harmful to humans.
My Department is not aware of any research having been conducted to investigate the way in which PB reacts when exposed to intense sunlight. However, the specification for NAPS tablets for use by UK forces requires that they are wrapped in lacquered aluminium foil which is light impermeable, and they would not therefore normally be exposed to sunlight until this wrapping had been broken open to allow the first tablet to be extracted for immediate consumption. As each packet of NAPS contains 21 tablets, one to be taken every 8 hours, a packet would normally be consumed within a week.