Coldwell R D, Nolan J, Trafford D J, Mawer E B, Makin H L
Department of Chemical Pathology, London Hospital Medical College, UK.
J Pharm Biomed Anal. 1992 Sep;10(9):631-7. doi: 10.1016/0731-7085(92)80090-a.
The use of octadecyl-bonded microparticulate silica to separate free and bound fractions during the saturation analysis of 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D has been investigated. A slurry of octadecyl-bonded silica in an appropriate incubation buffer was prepared and used in parallel with a conventional dextran-coated charcoal suspension in several assay procedures. Standard curves, non-specific binding and plasma values were compared. A competitive protein binding assay for 25-hydroxyvitamin D and two radioreceptor assays and one radioimmunoassay for 1,25-dihydroxyvitamin D were investigated. In most cases the octadecyl-bonded silica preparation gave the more favourable results; its action was rapid, time- and temperature-independent, and it produced low non-specific binding and higher B0 values in all the assays examined. It was in our hands easier to use than dextran-coated charcoal. The use of octadecyl-bonded silica is recommended as an efficient agent for the separation of free and bound fractions in the saturation analysis of vitamin D metabolites.
在25-羟基维生素D和1,25-二羟基维生素D的饱和分析中，研究了使用十八烷基键合微粒硅胶分离游离和结合部分的方法。制备了在适当孵育缓冲液中的十八烷基键合硅胶悬浮液，并在几种测定方法中与传统的葡聚糖包被活性炭悬浮液平行使用。比较了标准曲线、非特异性结合和血浆值。研究了25-羟基维生素D的竞争性蛋白结合测定法以及1,25-二羟基维生素D的两种放射受体测定法和一种放射免疫测定法。在大多数情况下，十八烷基键合硅胶制剂给出了更有利的结果；其作用迅速，与时间和温度无关，并且在所有检测的测定中产生低非特异性结合和更高的B0值。在我们手中，它比葡聚糖包被活性炭更易于使用。建议使用十八烷基键合硅胶作为在维生素D代谢物饱和分析中分离游离和结合部分的有效试剂。
