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In preclinical drug development, ex vivo and in vitro permeability studies are a decisive element for specifying subsequent development steps. In this context, reliability, physiological alignment and appropriate in vivo correlation are mandatory for predictivity regarding drug absorption. Especially in oromucosal drug delivery, these prerequisites are not adequately met, which hinders its progressive development and results in the continuous need for animal experiments. To address current limitations, an innovative, standardized, and controlled ex vivo permeation model was applied. It is based on Kerski diffusion cells embedded in automated sampling and coupled to mass spectrometric quantification under physiologically relevant conditions. This study aimed to evaluate the predictivity of the developed model using porcine mucosa (ex vivo) in relation to data of sublingual propranolol absorption (in vivo). In addition, the usefulness of biomimetic barriers (in vitro) as a replacement for porcine mucosa was investigated. Therefore, solubility and permeability studies considering microenvironmental conditions were conducted and achieved good predictivity (R2 = 0.997) for pH-dependent permeability. A multiple level C correlation (R2 ≥ 0.860) between obtained permeability and reported pharmacokinetic animal data (AUC, Cmax) was revealed. Furthermore, a point-to-point correlation was demonstrated for several sublingual formulations. The successful IVIVC confirms the standardized ex vivo model as a viable alternative to animal testing for estimating the in vivo absorption behavior of oromucosal pharmaceuticals.

Background Plasma renin levels were determined in the academia-driven, EU-funded “Labeling of Enalapril from Neonates up to Adolescents” (LENA) project to evaluate its role in pediatric heart failure. Quality-controlled bioanalysis is crucial to ensure reliable data generation. However, a comprehensive bioanalytical quality control (QC) concept to monitor the method performance within an academic environment was lacking. Methods Thus, a QC concept was designed encompassing regulatory guidance, international recommendations and current scientific discussions. The concept included (1) a system-suitability test, (2) verification of single bioanalytical runs by calibration curve performance and evaluation of QCs, (3) assessment of the inter-run accuracy according to Clinical Laboratory Standards Institute (CLSI) guideline, (4) monitoring of reproducibility by pediatric incurred samples, (5) blank-sample analysis and (6) participation in interlaboratory testing. Results The concept was successfully applied to the academic project. About 11% of single runs were identified as invalid and triggered a re-analysis of unknown samples being included in those runs. The usefulness of the customized inter-run monitoring was demonstrated and proved the good accuracy from the first to the last run. All 147 reanalyzed incurred sample pairs complied with regulatory requirements. Conclusions The regulatory complied QC concept was customized for the demands of academia-driven pediatric trials and contributed to the reliable quantification of 965 pediatric renin samples.

Item does not contain fulltext Aim: Clinical research in pediatrics is progressively initiated by academia. As the reliability of pharmacodynamic measures is closely linked to the quality of bioanalytical data, bioanalytical quality assurance is crucial. However, clear guidance on comprehensive bioanalytical quality monitoring in the academic environment is lacking. Methods & results: By applying regulatory guidelines, international recommendations and scientific discussions, a five-step quality control system for monitoring the bioanalysis of aldosterone by immunoassay was developed. It comprised performance qualification, calibration curve evaluation, analysis of the intra- and inter-run performance via quality control samples, incurred sample reanalysis and external quality assessment by interlaboratory testing. A total of 55 out of 70 runs were qualified for the quantification of aldosterone in the study sample enabling the evaluation of 954 pediatric samples and demonstrating reliability over the 29-month bioanalysis period. Conclusion: The bioanalytical quality control system successfully monitored the aldosterone assay performance and proved its applicability in the academic environment.

As part of early drug development, preformulation studies are used to comprehensively explore the properties of new drugs. In particular, this includes the biopharmaceutical characterization and evaluation of impacting factors (e.g. excipients, microenvironmental conditions etc.) by permeation studies. To overcome the limitations of current studies, a novel standardized ex vivo procedure using esophageal mucosa as surrogate has been established successfully and applied to preformulation studies for oromucosal delivery of cyclobenzaprine hydrochloride, a tricyclic muscle relaxant with potential for psychopharmacotherapeutic use. By using the standardized ex vivo permeation process, a twofold enhancement of permeability (0.98 ± 0.16 to 1.96 ± 0.10 * 10-5 cm/s) was observed by adjustment and controlling of microenvironmental pH, empowering a targeted and effective development of sublingual formulations. Predictivity and suitability were superior compared to in vitro experiments using artificial biomimetic membranes, revealing a determination coefficient (R2) of 0.995 vs. 0.322 concerning pH-dependent permeability of cyclobenzaprine. In addition, diffusion properties were extensively examined (e.g. influence of mucosal thicknesses, tissue freezing etc.). The alignment of the study design regarding physiologically/clinically relevant conditions resulted in ex vivo data that allowed for the estimation of plasma AUC levels in the extend of reported in vivo ranges.

Tissue-based ex-vivo studies on the oromucosal permeability of drugs are often insufficiently adapted to physiological and clinical conditions, which limits their predictivity. Moreover, the scientific community demands for the standardization of ex-vivo studies, since conceptual limitations (e.g. low sensitivity of analytical methods, insufficient monitoring, different designs) restrict the wide implementation in preclinical drug development. Therefore, an innovative ex-vivo permeation process consisting of novel Kerski diffusion cell coupled to fully automated sampling and sample preparation with LC-MS/MS quantification was developed and standardized. Novel assays for routine examination of tissue integrity and viability were developed and embedded in a comprehensive analytical control system. The high level of standardization and automation reduced the differences of between-run to within-run precision to ≤ 0.27 % CV. Successful validation proved a broad calibration range of 0.93-952.38 ng/mL of the model drug cyclobenzaprine with guideline-compliant relative errors from -7.9-12.6 % (between-run accuracy). Consequently, the method allowed the physiological-clinical alignment of the study conditions to therapeutic doses and the short residence time of intraoral drugs (sampling times 1-60 min). Applicability was demonstrated by assessing the oromucosal permeability for different sublingual cyclobenzaprine hydrochloride formulations representing the excipient selection as a common aspect during galenic development. Thereby, expressive evaluation of the dosage forms was achieved resulting in an improved permeation by replacing croscarmellose into polyvinylpyrrolidone (cumulative amount of 42.6 vs. 112.6 μg/cm²). Thus, the automated permeation process ensured lean, standardized and reproducible assessment of oromucosal permeability within quality-controlled academic and regulatory environments. Simultaneously, the improved ex-vivo predictivity through physiological-clinical adjustments facilitates the reduction of costly in-vivo studies.

BackgroundAs the initiator of the Renin-Angiotensin-Aldosterone-system, renin plays an essential role in the vicious circle of heart failure. Therefore, renin was determined in the investigators driven ‘Labelling of Enalapril from neonates up to adolescents’ (LENA) study to evaluate its role in paediatric heart failure. Due to the often long-lasting periods of recruitment of paediatric subjects, the assay performance has to be guaranteed over the whole recruiting time. Therefore, to ensure the high quality of the determined renin study samples after successful assay validation,1 a multi-step quality approach was used to get reliable results over a period of 30 months.MethodsBased on a multi-step quality approach consisting of calibration standards (CSs), quality controls (QCs) and incurred sample reanalysis (ISR), study samples of unknown renin concentrations were determined. Results within predefined limits of CSs (6 levels) and QCs according to European Medicine Agency (EMA) guidelines were required for evaluating the study samples.2 ISR was performed for randomly selected paediatric samples to evaluate the long-term accuracy of the validated assay.Results133 analytical runs were conducted for renin from February 2016 to August 2018. In 119 (88.8%) valid runs, a total number of 1414 of CCs and 952 of QCs were determined. Thereof 99.9% of CCs and 98.3% of QCs were in the predefined limits according to EMA. 143 incurred sample pairs were reanalysed resulting in 95.8% of samples within EMA guidelines. Using this multi-step quality approach, the reliable determination of 965 LENA paediatric study samples was guaranteed.ConclusionIn addition to the assay validation, the multi-step quality approach ensured the reliability of the determined renin concentrations in the continuous bioanalysis of the paediatric study samples and guaranteed the high quality of the collected data in the LENA study.ReferencesSchaefer J, Burckhardt BB, Tins J, et al. Validated low-volume immunoassay for the reliable determination of direct renin especially valuable for pediatric investigations. J Immunoass Immunochem 2017;38:579–94. doi:10.1080/15321819.2017.1350707Guideline on bioanalytical method validation. European Medicines Agency, London, UK (2011).Disclosure(s)Martin Feickert, Ilja Burdman, Nina Makowski, Moshin Ali, Anke Bartel, and Bjoern B. Burckhardt declare that there is no conflict of interest. The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007–2013) under grant agreement n°602295 (LENA)

BackgroundA validation is crucial to ensure the quality of an analytical method and its results. However, the validation is only a first step, further quality assessment has to be utilised to ensure high quality research. Specifications for the validation process, but also for the assessment of data, acquired in a study setting, are given by the EMA and FDA to ensure highest quality of the data.1 2MethodsA multi-level analytical quality system was established. Data of the calibration standards (CSs), quality control samples (QCs), and incurred sample reanalysis (ISR) were evaluated according to the specifications given by the EMA and FDA guidelines.[1,2] For a run to be considered valid ≥6 levels or 75% of the CSs and 67% of the QCs (≥50% per level) had to vary ≤±20% (LLOQ ≤±25%) from their nominal concentration.[1,2] For the ISR analysis at least 67% of the ISR samples have to lay in ±30% to the nominal concentration of the mean of the original and reanalysed value.[1]ResultsSeventy analytical runs were conducted, applying the quality measures, 79% runs were classified as valid and were used to determine unknown samples in a paediatric study. The high quality of the acquired data is reflected in the high conformity of the CSs and QCs to the EMA and FDA guidelines, 99% of the CSs and 95% of the QCs were accepted. Further underlining the high quality of the acquired data, 85% of the IRS have also been accepted. The assay was successfully used over a time period of 29 months.ConclusionThe results of the quality assessment confirmed the robustness of the aldosterone assay throughout the whole study duration. Thus, the samples measured by this assay are reliable and facilitate the high quality research in the paediatric population.ReferencesGuideline on bioanalytical method validation. European Medicines Agency, London, UK (2011).Guidance for Industry: Bioanalytical Method Validation. US Department of Health and Human Services, US FDA Rockville, MD, USA (2018).Disclosure(s)Nina Makowski, Ilja Burdman, Mohsin Ali, Bartel A, Bjoern B. Burckhardt declare that there is no conflict of interest. The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007–2013) under grant agreement n°602295 (LENA).