Table 3.
Relationship of zinc reaction products to efficacy.
| Trial (year) reference | N | Zinc compound reported to be tested | Filler/excipients | Other ingredients | Zinc reaction products | First stability constant (K1) of reaction product | Efficacy against common colds |
|---|---|---|---|---|---|---|---|
| Eby et al. [21] | 65 | Zinc gluconate | Dicalcium phosphate, microcrystalline cellulose, sodium starch glycolate | Magnesium stearate, coloring | Zinc gluconate | 1.7 | Yes |
| Al-Nakib et al. [34] | 12 | Zinc gluconate | Fructose | Methylcellulose, flavoring oil | Zinc gluconate | 1.7 | Yes |
| McCutcheon et al. [16] | 49 | Zinc aspartate | Sucrose, fructose | Calcium ascorbate, bee propolis, slippery elm, vitamin A palmitate, 2 stearates, Duratex™, spray-dried flavor oils, | Zinc aspartate | 5.8 | No |
| Farr et al. [36] | 77 | Zinc gluconate | Sugar, corn syrup | Citric acid, flavor oils | Zinc citrate | 4.8 | No |
| Douglas et al. [22] | 63 | Zinc acetate | Mannitol | Tartaric acid, sodium bicarbonate, flavor oils | Zinc tartarate | 2.9 | No |
| Zinc carbonate | Not soluble | ||||||
| Zinc mannitol | n.a. | No | |||||
| Smith et al. [40] | 110 | Zinc gluconate | Sucrose, fructose, sorbitol, mannitol | Mineral and acid stearates, Methocel®, pineapple powder and 3 spray-dried flavors | Zinc sorbitol and mannitol complexes | n.a | |
| Weisman et al. [41] | 130 | Zinc gluconate | Maltitol | Not stated | Zinc gluconate | 1.7 | No |
| Godfrey et al. [42] | 73 | Zinc gluconate | Sucrose, corn syrup | Glycine, flavor oils | Zinc glycinate | 4.8 | Yes |
| Mossad et al. [43] | 99 | Zinc gluconate | Sucrose, corn syrup | Glycine, flavor oils | Zinc glycinate | 4.8 | Yes |
| Macknin et al. [44] | 249 | Zinc gluconate | Sucrose, corn syrup | Glycine, flavor oils | Zinc glycinate | 4.8 | No |
| Petrus et al. [45] | 101 | Zinc acetate | Dextrose | Glycerol monostearate, stevia, peppermint oil, silica gel | Zinc acetate | 1.0 | Yes |
| Prasad et al. [46] | 48 | Zinc acetate | Dextrose | Glycerol monostearate, stevia, peppermint oil, silica gel | Zinc acetate | 1.0 | Yes |
| Turner et al. [47] | 275 | Zinc gluconate | Sucrose, glucose syrup | Glycine, flavor oils | Zinc glycinate | 4.8 | No |
| Turner et al. [47] | 552 | Zinc acetate | Sucrose, glucose syrup | Hydrogenated palm kernel oil, cotton seed oil, soy lecithin, Panoden™, flavoring and colors | Zinc stearate, zinc oleate, zinc palmitate | Not soluble | No |
| Eby and Halcomb [49] | 75 | Zinc orotate | Gum guar, cellulose | Silica, vegetable stearine | Zinc orotate | Essentially insoluble | No |
| Prasad et al. [11] | 50 | Zinc acetate | Sucrose, corn syrup | Cherry-flavoring oil | Zinc acetate | 1.0 | Yes |
n.a. = data not available.