RECOVERY STUDY OF MICROBIOLOGICAL SAMPLING METHODS TO SUPPORT CLEANING VALIDATION IN THE PHARMACEUTICAL INDUSTRY

Background: In the pharmaceutical industry, cleaning validation is a critical component of an effective quality assurance system to ensure compliance with the GMP requirements. FDA and EMA have guidance to perform cleaning validation, prevent cross-contamination and minimize patient safety risk but there is no regulatory guidance relating to microbiological aspects of cleaning validation, sampling techniques and establishing microbial contamination limits for pharmaceutical facilities. Therefore, there is a certain vacuum of regulations and basic principles, especially, methodologies to properly conduct cleaning validation focusing on microbiological contamination. Aim: This present work is dedicated to the development and validation of swab and rinse sampling methods of bioburden on manufacturing equipment surfaces in combination with microbiological testing methods, to demonstrate a suitable methodology in order to perform cleaning validation at an appropriate level in compliance with the GMP requirements. Methods: Swab and rinse sampling methods were used in this study. The swabbing procedure involved moistening the swab (10 cm) with the sterile saline and swabbing the area to be sampled in an overlapping zigzag pattern; Rinse sampling is performed with a fixed volume of sterile water for injection from a piece of equipment surface. Properly cleaned and sterilized coupons (100 cm2) of three different materials (plastic, glass, and stainless steel) were used and spiked (inoculated) with the fixed volume of the inoculum’s solution prepared by the working bacterial and fungi culture suspensions. After drying the surface, the swab and rinse sampling was performed to obtain test samples. Results and Discussion: Swab and rinse sampling methods were developed using five bacterial and fungal cultures and three different types of materials in order to obtain a good recovery (?37%) with high precision (RSD?15%). The recovery rates for all types of materials using the swab method ranged from 44 to 70%, while the rinse method was slightly lower, ranging from 35 to 57%. Depending on the type of coupon material, the recovery results of the test microorganisms are different. The decreasing tendency was revealed in the following order: plastic, stainless steel, and glass. Conclusions: The highest recovery was obtained in the case of E. coli for both sampling methods. The recovery rate for each test microorganism is higher for the swab sampling method (61 %) compared to the rinsing method (47 %). The proposed methodology can be used to control bioburden on the pharmaceutical equipment surfaces during microbiological monitoring process and successfully perform cleaning validation.