The reports are based on successful cell culture experiments microparticles produced using an acid-sensitive polymer, poly(cyclohexane-1,4-diyl acetone dimethylene ketal) (PCADK), for encapsulating SOD.
SOD has a different mode of action to vitamins. Dubbed 'the enzyme of life' when first discovered in 1968, it is the first antioxidant mobilized by the cell for defence. It is thought to be more powerful than antioxidant vitamins as it activates the body's productions of its own antioxidants, including catalase and glutathione peroxidase.
Lead author Sungmun Lee from the Georgia Institute of Technology and Emory University School of Medicine reports in the American Chemical Society's journal Bioconjugate Chemistry that application of PCADK for SOD delivery is promising because the polymer has both a straightforward synthesis and well-characterized degradation products.
Moreover, the hydrolysis products of PCADK are1,4-cyclohexanedimethanol, a compound used in food packaging and approved for human consumption in the US as an indirect food additive, and acetone, a compound on the FDA GRAS list.
The researchers synthesised the PCADK using the acetal exchange reaction between 1,4-cyclohexanedimethanol and 2,2-dimethoxypropane, with yields reported in the multigram scale in one step.
A double emulsion (water in oil in water) procedure was then used to encapsulate the SOD into the PCADK-based microparticles, with a resulting diameter ranging from three to 15 micrometres, determined using scanning electron microscopy (SEM).
"This may be beneficial in the case of SOD delivery, because superoxide causes both intracellular toxicity and extracellular tissue damage during inflammation," wrote the researchers.
They also note that the delivery system may have applications not only for SOD but also for pharmaceuticals: "We anticipate numerous applications of PCADK in drug delivery, based on its acid sensitivity, well-characterized degradation products, and straightforward synthesis."
Commenting independently on the research, François Vix, president of Isocell, producers of the GliSODin superoxide dismutase supplement, told NutraIngredients.com: "On paper it looks like an interesting delivery system but its major limitation is that it's only in vitro work with all the question marks as to how this delivery system would translate in in vivo work, not to mention the potential effectiveness of this delivered SOD in human clinical applications."
GliSODin is patented and trademarked by Paris-based Isocell. In North America PL Thomas distributes the ingredient.
Source: Bioconjugate Chemistry Published on-line, ASAP Article; doi: 10.1021/bc060259s "Polyketal Microparticles: A New Delivery Vehicle for Superoxide Dismutase" Authors: S. Lee, S.C. Yang, M.J. Heffernan, W.R. Taylor, and N. Murthy