Progress towards the Replacement of the Rabbit Blood Sugar Test for the Quantitative Determination of the Biological Activity of Insulins (USP <121>) with an In Vitro Assay.

For the quantification of insulin activity, United States Pharmacopeia (USP) general chapter <121> continues to require the rabbit blood sugar test. For new insulin or insulin analogue compounds, those quantitative data are expected for stability or comparability studies. At Sanofi, many rabbits were used to fulfil the authority's requirements to obtain quantitative insulin bioactivity data until the in vivo test was replaced. In order to demonstrate comparability between the in vivo and in vitro test systems, this study was designed to demonstrate equivalency. The measurement of insulin lispro and insulin glargine drug substance and drug product batches, including stress samples (diluted or after temperature stress of 30 min at 80 °C), revealed a clear correlation between the in vitro and in vivo test results. The recovery of quantitative in vitro in-cell Western (ICW) results compared to the in vivo test results was within the predefined acceptance limits of 80% to 125%. Thus, the in vitro ICW cell-based bioassay leads to results that are equivalent to the rabbit blood sugar test per USP <121>, and it is highly suitable for insulin activity quantification. For future development compounds, the in vitro in-cell Western cell-based assay can replace the rabbit blood sugar test required by USP <121>.

In vitro Stability of Biosimilar Insulin Aspart SAR341402 in the Medtronic MiniMed Insulin Pumps.

SAR341402 (Insulin aspart Sanofi®) is an insulin aspart biosimilar that can be used for continuous subcutaneous insulin infusion (CSII) in pump systems. The physicochemical stability of SAR341402 for CSII use was evaluated in several in vitro experiments. Insulin aspart products (SAR341402, NovoLog®, NovoRapid®) were filled into pump reservoirs and pumped through Medtronic insulin pumps (MiniMedTM 530G-Model 751, Medtronic, Northridge, CA) and their related infusion sets under simulated stress conditions, including elevated temperature and mechanical agitation on a continuously vibrating platform, up to 13 days. Samples pumped through the infusion sets and retained in reservoirs (non-pumped) were analyzed using suitable analytical methods. All products showed stable insulin aspart content and no unwanted impurities. Minor pH changes were seen in all products but were not considered relevant. A time-dependent increase in high-molecular-weight proteins and largest other insulin aspart impurities was observed for each product but each remained within acceptance limits. Concentrations of phenol and metacresol decreased but remained at levels to ensure preservative efficacy. Samples collected from the infusion sets were clear of visible particles and showed comparable subvisible particle counts. No occlusion events were observed. Leachable profiles from pump and reservoir samples were similar in all product batches. Like NovoLog®/NovoRapid®, SAR341402 demonstrates appropriate physicochemical stability when used in these insulin pump systems.

Photoactivated Preparation and Patterning of Self-Assembled Monolayers with 1-Alkenes and Aldehydes on Silicon Hydride Surfaces.

Direct lateral patterning in the formation of self-assembled monolayers (SAMs) on silicon was achieved by the photoinduced reaction of aldehydes with Si(111)-H surfaces by using the usual masking techniques (see the schematic illustration; on the right-hand side is a microscopy image of a patterned SAM formed from octadecanal).