Direct enzymatic assay for %HbA1c in human whole blood samples.

OBJECTIVES: Development and validation of a direct enzymatic HbA1c assay that utilizes a single channel on chemistry auto-analyzers without the need to run separate glycated hemoglobin and total hemoglobin assays. DESIGN AND METHODS: An enzyme based single channel assay was developed to measure %HbA1c in human whole blood samples. The performance characteristics of the Diazyme Direct Enzymatic HbA1c Assay were evaluated on the Hitachi 917 auto-analyzer using whole blood samples, appropriate controls and a reference lot of manufactured reagents. Accuracy studies were completed by comparing the Direct Enzymatic Assay to existing HPLC and immunoassay methods. Interference testing was performed to determine the effect of total hemoglobin, glycated serum proteins, chemical substances and hemoglobin variants in patient samples. RESULTS: The Direct Enzymatic HbA1c Assay showed within run precision and total precision results of < or = 2% CV for both normal and abnormal level samples. Method comparison studies showed that there was a good correlation between the Direct Enzymatic HbA1c and the HPLC (R(2)=0.98) or the immunoassay (R(2)=0.97) methods. The assay measured within the range of 4-16% HbA1c and showed excellent performance with variant hemoglobin in samples. CONCLUSIONS: Diazyme Direct Enzymatic HbA1c Assay is accurate and precise when compared to currently marketed medical devices. The assay is designed to report %HbA1c values directly without need for a separate measurement of total hemoglobin and is not adversely affected by interferences from common hemoglobin variants in samples. It is a cost effective, user-friendly method and is adaptable to most general chemistry analyzers.

Synthesis and biological evaluation of 6-aryl-6H-pyrrolo[3,4-d]pyridazine derivatives as high-affinity ligands of the alpha(2)delta subunit of voltage-gated calcium channels.

A novel class of 2H-pyrrolo[3,4-c]pyridazine ligands of the alpha (2) delta subunit of voltage-gated calcium channels is described. Compound 4a with high affinity toward alpha (2) delta was identified through structure-activity relationship studies of the lead compound. Tritiated ligand [(3)H]-4b was synthesized to demonstrate that this ligand binds to the same site as Gabapentin toward alpha (2) delta subunit of voltage-gated calcium channels.

Identification and synthesis of [1,2,4]triazolo[3,4-a]phthalazine derivatives as high-affinity ligands to the alpha 2 delta-1 subunit of voltage gated calcium channel.

We have identified and synthesized a series of [1,2,4]triazolo[3,4-a]phthalazine derivatives as high-affinity ligands to alpha 2 delta-1 subunit of voltage gated calcium channels. Structure-activity relationship studies directed toward improving the potency and physical properties of 2 lead to the discovery of 20 (IC(50)=15 nM) and (S)-22 (IC(50)=30 nM). A potent and selective radioligand, [(3)H]-(S)-22 was also synthesized to demonstrate that this ligand binds to the same site as gabapentin.

N-Acridin-9-yl-butane-1,4-diamine derivatives: high-affinity ligands of the alpha2delta subunit of voltage gated calcium channels.

A series of N-acridin-9-yl-butane-1,4-diamines were found to be high-affinity ligands of the alpha(2)delta subunit of voltage gated calcium channels. The SAR studies of butane-1,4-diamine side chain resulted in the identification of compound 10 (IC(50)=9 nM), which is more potent than gabapentin (IC(50)=27 nM). Partial saturation of the acridine ring was also pursued and provided a compound with higher binding affinity than 1.