By John Heptonstall
In September 2010 the Medicines and Healthcare products Regulatory Agency, MHRA, which is the government agency responsible for regulating medicines and medical devices in the UK, reported that there was a risk of aluminium exposure caused by calcium gluconate injection 10% in 10ml glass containers. Calcium Gluconate is licensed for use in certain acute conditions such as hypocalcaemia and cardiac resuscitation. It has been found that Calcium Gluconate solution in glass vials contains almost 200 times more aluminium than Calcium Gluconate in plastic vials; this is due to the solution leeching aluminium from the glass.
Increased aluminium levels can cause aluminium toxicity with adverse effects on bone minerlisation and neurological development, particularly in persons with kidney impairment and children. It is believed that the aluminium leeches from the glass into the solution during autoclaving or storage, although plastic storage vials did not increase aluminium levels. Aluminium levels in glass ampoules of calcium gluconate (in ug/L) in long storage were 6135 and short storage were 4890, these compared with levels in plastic ampoule storage of 31 and 27 respectively; there seemed to be a greater concentration of aluminium in old as compared to new glass vials. It is usual that neonates are fed with parenteral nutrition solutions that have been prepared from Calcium Gluconate injections and so they may have been subjected to unacceptably high levels of aluminium during prolonged feeding periods. Bohrer et al 2003 (HERE) note that aluminium release is enhanced from glass ampoules when containing solutions with Calcium and Phosphorus salts. Frey and Maier 2000 found less aluminium contamination in Calcium Gluconate packaged in polyethylene containers (195ug/L) compared to glass vials (5000ug/L).
Why has taken the MHRA so long to report this and what consequences will the MHRA conclusions have on all glass packaging of medicines, foods, and other substances intended for human consumption?