A multilaboratory validation study of LC/MS biomarker assays for three lysophosphatidylcholines.

Aim: Although the fit-for-purpose approach has been proposed for validation procedures and acceptance criteria for biomarker assays, practical biomarker assays to facilitate clinical application and regulatory documents on biomarker assays remain limited. Materials & methods: We assigned six independent laboratories and selected three lysophosphatidylcholines (LPCs): LPC(16:0), LPC(18:0) and LPC(18:1) as model biomarkers. Using LC-MS, the following key validation parameters were evaluated: calibration curve, carryover, parallelism, precision and relative accuracy and these values were similar among all laboratories. Further, we determined LPC levels in six lots of rat plasma at unknown concentrations and compared them among the laboratories. Conclusion: Our multilaboratory validation and reproducibility data are useful for the development of future biomarker assay validation procedures, as well as regulatory documents.

Highlights of the 12th Japan Bioanalysis Forum Symposium.

Approximately 300 people associated with pharmaceutical industries, contractors, academic institutions and regulatory authorities attended the 12th Japan Bioanalysis Forum Symposium. The webinar was conducted from 9 to 11 March 2021. The theme of the symposium was 'for the next generation', and the event provided 'an opportunity for young researchers in bioanalysis (including students)' and 'an opportunity to discuss new frontiers of bioanalysis'. The speakers focused on hot topics of bioanalysis, including biomarker analysis, patient centric sampling, virtual clinical trials, gene therapy, cancer genome medicine and therapeutic middle molecules. The symposium presented a platform for the discussion of the prospects and challenges facing bioanalysts working in the field of pharmacokinetics. This report presents the key issues discussed.

The 10th Japan Bioanalysis Forum Symposium conference: a report.

The Japan Bioanalysis Forum Symposium was held on 12-14 February 2019 (Yokohama, Japan), in celebration of its 10th anniversary, and over 370 participants from pharmaceutical industries, contractors, academia and regulatory authorities from home and abroad came together in Yokohama. The 3-day symposium particularly aimed to foster collaboration with the scientists surrounding bioanalysts, according to the theme 'Open to the Public.' The symposium also included a broad range of pioneering programs, such as lectures by speakers from DMPK/metabolomics fields, discussions of future bioanalysis and poster presentations by publicly offered presenters as well as the regular ones we had organized. This report summarizes the major topics as a conference report.

Proposal for risk-based scientific approach on full and partial validation for general changes in bioanalytical method.

The guidance and several guidelines on bioanalytical method validation, which were issued by the US FDA, EMA and Ministry of Health, Labour and Welfare, list the 'full' validation parameters; however, none of these provide any details for 'partial' validation. Japan Bioanalysis Forum approved a total of three annual discussion groups from 2012 to 2014. In the discussion groups, members from pharmaceutical companies and contract research organizations discussed the details of partial validation from a risk assessment viewpoint based on surveys focusing on bioanalysis of small molecules using LC-MS/MS in Japan. This manuscript presents perspectives and recommendations for most conceivable changes that can be made to full and partial validations by members of the discussion groups based on their experiences and discussions at the Japan Bioanalysis Forum Symposium.

[Discussion on Partial Validation in Small Molecule Regulated Bioanalysis: Change in Analytical Instruments].

In recent years, the necessity of a bioanalytical method validation has been discussed and guidance/guidelines have been released from regulatory agencies. However, none of these provides any details for partial validation (PV) in case of a partial change in the validated analytical method. Therefore eleven scientists have launched a discussion group (DG) with the approval of Japan Bioanalysis Forum (JBF), and have been discussing PV for chromatographic methods based on survey results of Japanese bioanalysts. This document reports the results of discussion on PV for a change of analytical instruments such as: 1) full system (limited to same manufacturer and model); 2) pump; 3) autosampler; and 4) mass spectrometer. The DG members agreed on an outline that validation items required for PV are as follows: calibration curve and reproducibility in case 1); calibration curve, reproducibility, and selectivity in case 2); calibration curve, reproducibility, and carryover in case 3); and nearly full validation items without recovery, dilution integrity, and stability in case 4), in consideration of instrument specification and characteristics of each analytical method. Note that this report does not represent a consensus of all the members of JBF, but is a recommendation from the DG members at this stage. Thus further thought is recommended for future discussions.

Characterization of gastrointestinal absorption of digoxin involving influx and efflux transporter in rats: application of mdr1a knockout (-/-) rats into absorption study of multiple transporter substrate.

1. This study was aimed to characterize gastrointestinal absorption of digoxin using wild-type (WT) and multidrug resistance protein 1a [mdr1a; P-glycoprotein (P-gp)] knockout (-/-) rats. 2. In WT rats, the area under the plasma concentration-time curve (AUC) of oral digoxin increased after oral pretreatment with quinidine at 30 mg/kg compared with non-treatment, but the increasing ratio tended to decrease at a high dose of 100 mg/kg. In mdr1a (-/-) rats, however, quinidine pretreatment caused a dose-dependent decrease in the AUC. 3. Quinidine pretreatment did not alter the hepatic availability of digoxin, indicating that the changes in the digoxin AUC were attributable to inhibition of the absorption process by quinidine; i.e. inhibition of influx by quinidine in mdr1a (-/-) rats and inhibition of efflux and influx by quinidine in WT rats. 4. An in situ rat intestinal closed loop study using naringin implied that organic anion transporting peptide (Oatp) 1a5 may be a responsible transporter in the absorption of digoxin. 5. These findings imply that the rat absorption behavior of digoxin is possibly governed by Oatp1a5-mediated influx and P-gp-mediated efflux. The mdr1a (-/-) rat is therefore a useful in vivo tool to investigate drug absorption associated with multiple transporters including P-gp.