Settling and Impaction of Particles into Containers in Manufacturing Pharmacies

Abstract

Particles present in the air of a manufacturing pharmacy may be deposited or impacted into a container. Product contamination is dependent on the concentration of airborne particulate matter, the area of the neck of the container, the velocity of the air round the container neck, the time the container is open, the speed of filling and the airspace left in the container. A theoretical model has been derived which can be used to estimate the number of particles that may enter a container from the air. Calculations made to determine the number of bacterial and inanimate particles contaminating containers which are terminally sterilised, clearly show that contamination with small particles and bacteria through the airborne route is not a significant one, although airborne contamination by large particles could be significant. In an aseptic area, where very small amounts of airborne bacterial contaminants are not acceptable, the theoretical model shows that the present airborne standards are sufficient, yet not excessively so, to ensure that product contamination will not exceed WHO requirements (0.3%) (I). A method is given for calculating the airborne contamination concentrations which should not be exceeded during a given manufacturing process, given the maximum product contamination rate and the values of the variables which will affect the airborne contamination of the product.