Glycoconjugate content quantification to assess vaccine potency: A simplified approach.

Several glycoconjugate vaccines have been licensed or are currently in clinical development to prevent bacterial infections. Here we report the development of a single analytical assay to quantify the conjugated saccharide content, as alternative to two separated total and free (unconjugated) saccharide assays used so far, for a quadrivalent conjugate vaccine containing meningococcal serogroup A polysaccharide (α-1,6-linked N-acetylmannosamine phosphate repeating unit partly O-acetylated at position C3 or C4) coupled with CRM197 protein. The results confirm a high linear correlation among the two approaches (conjugated saccharide content vs. difference of total saccharide and free saccharide). Conjugated saccharide content estimation is therefore demonstrated to be a suitable method to monitor the product quality of vaccines containing meningococcal serogroup A conjugate antigen, in the final filled presentation as demonstrated here and potentially on the bulk conjugate before formulation.

Development of a New Solid-Phase Extraction Base Method for Free Saccharide Content Estimation of Meningococcal Conjugate Vaccines.

GlaxoSmithKline (GSK) is currently developing a fully liquid presentation to ease the administration of the licensed quadrivalent conjugate vaccine (Menveo) against meningococcal serogroup A, C, W, and Y (MenACWY) infections. Herein, we report a new method for determining the free saccharide (FS) content of CRM197-MenACWY conjugated antigens, with the aim of improving accuracy and reproducibility. Mathematical models have been used to support technical knowledge in reducing the need for experimental development. This results in an improved, faster, and platform-based technique for FS separation with one single pretreatment applicable to all antigens of the multivalent meningococcal vaccine.

Clinically proven specification setting for a meningococcal serogroup a conjugate vaccine.

GSK is currently working to improve the commercial presentation of the licensed quadrivalent conjugate vaccine (Menveo) for use against meningococcal serogroup A, C, W, Y (MenACWY) infections. Menveo consists of a primary, lyophilized vial, containing the serogroup A antigen that is reconstituted with the content of a second, liquid, vial that contains the serogroup C, W, Y antigens, to give the final liquid MenACWY product. Since the MenA structure is prone to hydrolytic degradation in liquid formulations, we used mathematical models to rationally design a clinical Phase 2 development plan and provide end of shelf-life (EoSL) and release specification setting for the MenACWY liquid product. By using development and clinical stability data, statistical models were built and used to predict both the MenA free saccharide (FS) and O-Acetyl (OAc) content during long-term storage conditions at 5 °C and stressed (accelerated) stability studies at 15 °C, 22.5 °C, 25 °C, 37 °C and 50 °C. This approach allowed us to define an aging plan for the clinical material to reach at least the required levels of MenA FS and OAc levels at product EoSL. The clinical material was then exposed to a temperature of 22.5 ± 2.5 °C for 59 days to generate FS OAc content of about 35% and 40%, respectively, which was then delivered to the patients in the clinical trial. To the best of our knowledge, this work represents the first example in the field of vaccine research where statistical models have been used to rationally design tailored lots, with the goal of setting EoSL and release specification limits based on data collected on artificially aged clinical material, in which the FS and OAc levels tested were intended to support a product shelf-life of at least 24 months.

Pulmonary spray dried powders of tobramycin containing sodium stearate to improve aerosolization efficiency.

PURPOSE: Tobramycin microparticulate powders containing the hydrophobic adjunct sodium stearate were studied for their use as pulmonary formulations in dry powder inhalers. METHODS: Spray-dried powders were characterized in terms of particle size distribution, morphology, crystallinity, drug dissolution rate, toxicity on epithelial lung cells and aerosol efficiency. RESULTS: The presence of the sodium stearate had a direct influence on the aerosol performance of tobramycin spray-dried powders. Powders containing 1% w/w sodium stearate had fine particle fraction FPF of 84.3 +/- 2.0% compared to 27.1 +/- 1.9% for powders containing no adjunct. This was attributed to the accumulation of sodium stearate at the particle surface. Powders with higher sodium stearate concentrations (2% w/w) showed significantly lower FPF (66.4 +/- 0.9%) and less accumulation of sodium stearate at the particle surface. This was attributed to the formation of adjunct micelles, which remained internalised in the particle structure due to their reduced tropism toward the drying drop surface and molecular mobility. Preliminary analysis of the toxicity effect of sodium stearate on A549 cell lines showed that the adjunct, in the concentration used, had no effect on cell viability over a 24-h period compared to particles of pure tobramycin. CONCLUSIONS: Tobramycin pulmonary powders with low level of sodium stearate, presenting high respiration performances and no overt toxicity on lung cells, could be used to improve therapeutic outcomes of patient with Cystic Fibrosis (CF).