Performance Equivalence and Validation of a Rapid Microbiological Method for Detection and Quantification of Yeast and Mold in an Antacid Oral Suspension

Abstract

Alternative and rapid microbiological methods can be effective replacements for more traditional plating approaches for ensuring quality and safety in the pharmaceutical industry. This article compares the efficacy of the Soleris automated method and the traditional plate-count method for the quantitative detection of yeasts and molds at three different microbial bioburden levels. Validation testing was carried out using an antacid oral suspension (aluminum hydroxide 4% + magnesium hydroxide 4% + simethicone 0.4%). Equivalence of data between detection time and colony-forming units was established for both the alternative and the conventional methodologies. Using probability of detection, linear Poisson regression, Fisher's test, and multifactorial analysis of variance (ANOVA), all results from the rapid method were shown to be in statistical agreement with the those of the reference plating procedures. The limits of detection and quantification were statistically similar for both methods (Fisher's exact test, P > 0.05), showing that the alternative method is not inferior in performance to the reference method. Essential validation parameters such as precision (standard deviation <5, coefficient of variance <35%), accuracy (>70%), linearity (R² >0.9025), ruggedness (ANOVA, P < 0.05), operative range, and specificity were determined. It was shown that all the test results obtained using the alternative method were in statistical agreement with the those of the standard plate-count method. Thus, this new technology was found to meet all the validation criteria needed to be considered as an alternative method for yeast and mold quantification in the antacid oral suspension tested. However, taking into account that the present validation was carried out utilizing A. brasiliensis and C. albicans as suitable models for yeasts and molds and with an antacid oral suspension as a pharmaceutical matrix, further investigation will be required to qualify Soleris technology for other environmental isolates and recovery of these isolates from production batches.

Keywords: Alternative microbiological methods (AMM); Microbiological quality control; Rapid microbiological methods (RMM); Validation testing; Yeast and mold quantification.