Advancing multiproduct resin reuse for development and clinical manufacturing of an antibody-based therapeutic

Chromatography resins used for purifying biopharmaceuticals are generally dedicated to a single product. For clinical manufacturing, this can result in resin being used only for a fraction of its potential lifetime. Extending the use of resins to multiple products can significantly reduce resin waste and cost. It can also improve manufacturing flexibility in case of raw material shortage during times such as the COVID-19 pandemic. The work presented herein describes an overarching multiproduct resin reuse (MRR) strategy, which includes a risk assessment, strategic planning, small-scale feasibility runs, and the successful execution of the MRR strategy to support Good manufacturing practice (GMP) clinical manufacturing of an antibody-based therapeutic. Specifically, an anion exchange (AEX) and cation exchange (CEX) MRR strategy is described. Clearance of carryover biological product is demonstrated by first cleaning the AEX and CEX manufacturing columns with sodium hydroxide to ensure inactivation and degradation of the carryover protein and followed by a blank buffer elution that is tested using various analytical methodologies to ensure reduction of the carryover protein to an acceptable level. To our knowledge, this is the first time an MRR approach has been successfully implemented and submitted to health authorities to support biologic GMP clinical manufacture.

Probing the ionic atmosphere of single-stranded DNA using continuous flow capillary electrophoresis and fluorescence correlation spectroscopy

Two-beam fluorescence cross-correlation spectroscopy coupled with continuous flow capillary electrophoresis (2bFCCS-CFCE) was used to study the relationship between diffusion and effective charge of a fluorescently labeled 40-base polythymine single-stranded DNA (ssDNA) as a function of Mg2+ concentration. Cross-correlation analysis of the fluorescence monitored from two spatially offset microscopic detection volumes revealed the diffusion and electrophoretic migration of ssDNA at a range of Mg2+ concentrations and electric field strengths. The effective charge of the ssDNA could then be determined using simple calculations. It was found that as the Mg2+ concentration in the buffer solution increased, the diffusion of the ssDNA also increased, while the effective charge of the ssDNA decreased. This was believed to be caused by increased association of the Mg2+ counterions with the negatively charged backbone of the ssDNA, which partially neutralized the negatively charged functional groups and allowed the ssDNA to adopt a more compact structure. To our knowledge, this is the first demonstration of the measurement of effective charge of ssDNA in relation to Mg2+ concentration.

Minnesota Preschool Affect Rating Scales: development, reliability, and validity

Assessing the impact of disease and treatment of the emotional state and temperament of preschool children has been limited by the lack of sensitive and objective measurement techniques. To construct such a measure for longitudinal use, a sample of 179 children with febrile seizures and 85 normal children were used to develop the Minnesota Preschool Affect Rating Scales (MN-PARS). Video-taped play sessions were a source of behaviorally anchored ratings on 12 scales. Factor analysis yielded three factors of Negative Affect, Positive Affect, and Self-regulation with additional individual scales of Dependency and Activity Level. These scales and factors yield reliable ratings, as measured by interrater agreement and split-half techniques, as well as initial evidence of concurrent validity. Although they were developed for measuring the behavioral effects of phenobarbital on children with febrile seizures, these scales provide an objective means of measuring emotional expression and self-regulation useful for other studies.