Predictive scaling of fiber-based protein A capture chromatography using mechanistic modeling.

Protein A affinity chromatography is an important step in the purification of monoclonal antibodies (mAbs) and mAb-derived biotherapeutics. While the biopharma industry has extensive expertise in the operation of protein A chromatography, the mechanistic understanding of the adsorption/desorption processes is still limited, and scaling up and scaling down can be challenging because of complex mass transfer effects in bead-based resins. In convective media, such as fiber-based technologies, complex mass transfer effects such as film and pore diffusions do not occur which facilitates the study of the adsorption phenomena in more detail and simplifies the process scale-up. In the present study, the experimentation with small-scale fiber-based protein A affinity adsorber units using different flow rates forms the basis for modeling of mAb adsorption and elution behavior. The modeling approach combines aspects of both stoichiometric and colloidal adsorption models, and an empirical part for the pH. With this type of model, it was possible to describe the experimental chromatograms on a small scale very well. An in silico scale-up could be carried out solely with the help of system and device characterization without feedstock. The adsorption model could be transferred without adaption. Although only a limited number of runs were used for modeling, the predictions of up to 37 times larger units were accurate.

In Vitro Flow Rate Dependency of Delivered Dose and Fine Particle Dose of Salmeterol/Fluticasone Propionate Easyhaler and Seretide Diskus with Patient Flow Rates Collected in a Randomized Controlled Trial.

BACKGROUND: The Easyhaler® device-metered dry powder inhaler containing Salmeterol and Fluticasone propionate (S/F) has been developed for the treatment of patients with asthma and chronic obstructive pulmonary disease (COPD). We report two studies which evaluated the in vitro flow rate dependence of delivered dose (DD) and fine particle dose (FPD) of S/F Easyhaler versus Seretide Diskus®. METHODS: A randomized controlled trial (RCT) assessed inspiratory flow parameters of S/F Easyhaler and Seretide Diskus in subgroups of patients with asthma (children, adolescents and adults, and elderly) and in COPD patients. The 10th, 50th, and 90th percentile airflow rates were determined and utilized in vitro, to evaluate flow rate dependence of DD and FPD. Flow rate dependence was evaluated relative to the result obtained at the 50th percentile and any values deviating from 100% indicated flow rate dependence. The volumetric flow rate dependence (Q) index derived from FPD at 10th and 90th percentile airflows was also evaluated. RESULTS: Overall, 227 patients were enrolled and randomized; 216 completed the RCT. In total, 55.5% of patients were female, and the mean age was 46.3 years. Clinically relevant airflow rates (46, 68, and 85 L/min for S/F Easyhaler and 44, 71, and 96 L/min for Seretide Diskus) were carried forward into the in vitro study, which demonstrated similar flow rate dependence of DD and FPD for S/F Easyhaler compared with Seretide Diskus; all values were within ±15% limits across the 10th, 50th, and 90th percentile airflow rates. Q index results suggested that both S/F Easyhaler and Seretide Diskus are medium airflow-dependent products. CONCLUSIONS: Similar in vitro flow rate dependence of DD and FPD was demonstrated for S/F Easyhaler compared with Seretide Diskus, across a range of clinically relevant airflow rates, collected from patients with asthma and COPD.

Evaluation of in vitro and in vivo flow rate dependency of budesonide/formoterol Easyhaler(®).

BACKGROUND: The Easyhaler(®) (EH) device-metered dry powder inhaler containing budesonide and formoterol is being developed for asthma and chronic obstructive pulmonary disease (COPD). As a part of product optimization, a series of in vitro and in vivo studies on flow rate dependency were carried out. METHODS: Inspiratory flow parameters via EH and Symbicort(®) Turbuhaler(®) (TH) inhalers were evaluated in 187 patients with asthma and COPD. The 10(th), 50(th), and 90(th) percentile flow rates achieved by patients were utilized to study in vitro flow rate dependency of budesonide/formoterol EH and Symbicort TH. In addition, an exploratory pharmacokinetic study on pulmonary deposition of active substances for budesonide/formoterol EH in healthy volunteers was performed. RESULTS: Mean inspiratory flow rates through EH were 64 and 56 L/min in asthmatics and COPD patients, and through TH 79 and 72 L/min, respectively. Children with asthma had marginally lower PIF values than the adults. The inspiratory volumes were similar in all groups between the inhalers. Using weighted 10(th), 50(th), and 90(th) percentile flows the in vitro delivered doses (DDs) and fine particle doses (FPDs) for EH were rather independent of flow as 98% of the median flow DDs and 89%-93% of FPDs were delivered already at 10(th) percentile air flow. Using±15% limits, EH and TH had similar flow rate dependency profiles between 10(th) and 90(th) percentile flows. The pharmacokinetic study with budesonide/formoterol EH in healthy subjects (n=16) revealed a trend for a flow-dependent increase in lung deposition for both budesonide and formoterol. CONCLUSIONS: Comparable in vitro flow rate dependency between budesonide/formoterol EH and Symbicort TH was found using the range of clinically relevant flow rates. The results of the pharmacokinetic study were in accordance with the in vitro results showing only a trend of flow rate-dependant increase in lung deposition of active substances with EH.