Development and validation of a noncompetitive electrochemiluminescence-based immunoassay (ECLIA) for specific determination of insulin lispro (Humalog®) in human serum to support pharmacokinetic assessments.

Despite the importance of insulin and insulin analogs as therapeutic agents for the treatment of type I and II diabetes mellitus (DM), bioanalysis to support regulatory submissions of analogs remains a challenging endeavor. In particular, quantitation of insulin lispro by immunoanalytical methods has largely been limited to assays that display a high degree of cross-reactivity to native insulin because this analog shares extensive primary sequence homology with endogenous insulin and its efficacious circulating concentrations are low. We report herein development of the first noncompetitive electrochemiluminescence-based immunoassay (ECLIA) for specific determination of insulin lispro in serum or plasma. The new sandwich ECLIA permits accurate assessment of insulin lispro pharmacokinetics without interference from endogenous insulin. Integral to the development of this specific immunoassay was establishment of a proprietary process for affinity production of an oligoclonal monospecific guinea pig antiserum to the unique subtle structural modification in insulin lispro. We specifically optimized the ECLIA to provide reliable performance for supporting pharmacokinetic assessments in the pharmacologically relevant concentration range from 50.0 to 5,000 pM with robust performance up to 100,000 pM upon dilution. We concluded the new noncompetitive ECLIA represents a useful and convenient immunoassay for accurate quantitation of insulin lispro during pharmacokinetic assessments.

Critical reagent inventory management system and web portal specifically optimized for supporting external clients.

High-quality critical reagents are essential for the establishment of robust ligand binding assays to support regulated bioanalysis. To ensure consistency in assay performance over the lifetime of a project, a well-defined set of processes is needed for critical reagent life cycle management. Moreover, contract research organizations must support reagent life cycle management for diverse global clients. To address these needs, the authors designed and implemented a customized inventory management system, known as LCM+. This software solution provides external clients with efficient, secure access via a web portal to their critical reagent information, pertinent documentation and inventory tracking. Hence, the authors believe that LCM+ can serve as a useful prototype to aid the design of future inventory management systems for optimal management of critical reagents.

The impact of decreased bead count to determine concentrations of amyloid beta1-42, total-tau, and phosphorylated-tau181 in human cerebrospinal fluid using xMAP technology.

Alzheimer's disease is the leading cause of human dementia. The lack of diagnostic tests and limited therapeutic options has driven the search for endogenous biomarkers. The INNO-BIA AlzBio3 assay is a multiplex flow-based immunoassay measuring Aß42, tau, and p-tau in cerebrospinal fluid (CSF). This study assesses assays performance under varying bead count (BC) parameters. Original method validation parameters at 100 BC were acceptable. Reanalyses performed at 3, 10, 25, and 50 BCs were compared to 100 BC data by ANOVA, Bland-Altman analysis, evaluation of concordance correlation coefficients, and frequency distribution of coefficient of variation (CV) ranges. Method validation characteristics were acceptable with 100 BCs. Equivalency for 25 and 50 versus 100 BCs was demonstrated, but not for 3 and 10 BCs. A general trend of decreasing agreement between decreasing BCs and the 100 BC reference resulted in decreases in concordance coefficients ρ(c) . The frequency of CV values greater than 20% increased with decreasing BCs, and CV values of 5% or less decreased with decreased BCs. Statistical analyses demonstrate that BCs of 3 and 10 are not equivalent with the reference and should not be used as a basis for determination of Aß42, tau, and p-tau concentration in human CSF.