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W Whyte

Publications and source records attributed to W Whyte.

51 records · Page 3Linked to original sources
PubMedDate not supplied

Microbial growth in small-volume pharmaceuticals.

The ability of aseptically filled pharmaceuticals to support microbial growth was tested on 43 small-volume products (mainly parenterals). These were inoculated with a variety of microorganisms which were known to be associated with contamination of pharmaceutical products. In general, Gram-negative bacteria were found to be much more likely to grow than Gram-positive. It was possible for an inoculum of a few cells to multiply to levels up to 10(7)/mL. The presence of preservatives also influenced the likelihood of growth, 12 out of 19 (63%) of the pharmaceuticals without preservatives supporting growth of one or more microorganisms; only 3 out of 24 (12%) of those with preservatives supported growth. The importance of these observations is discussed with reference to formulation of aseptically filled products, environmental sampling and the quality of cleanroom conditions necessary for production. It is suggested that those pharmaceuticals which are designed to be sterile but not to be terminally sterilized, should be tested before production begins, for their ability to support microbial growth. In this way, the risks involved in aseptically filling can be ascertained. A test is proposed in which "indicator" microorganisms would predict the likelihood of pharmaceutical formulations supporting growth.

Drug Contamination↗
PubMedDate not supplied

In support of settle plates.

During pharmaceutical production the quality of the air in manufacturing areas is monitored by volumetric samplers and settle plates. Settle plates are often assigned a secondary role, their usefulness in predicting airborne contamination of containers not being fully recognised. In this paper criticisms of settle plates are answered and the advantages of settle plates explained. It is concluded that using settle plates is the best method of quantifying the likely airborne microbial contamination of containers filled in pharmaceutical production areas.

Air Microbiology↗
PubMedDate not supplied

Airborne contamination during blow-fill-seal pharmaceutical production.

The routes of airborne contamination, during Blow-Fill-Seal (BFS) production, were studied using tracer gas, particles and bacteria. The prevention of airborne contamination, by the air shower at the point of fill, was effective (> 99.2% efficient). However, microbe-carrying particles could gain access, by deposition or air exchange, when the containers were cut open and before they shuttled under the protection of the air shower. The use of SF6 tracer gas demonstrated that when the air shower was not on, 50% of the air within the containers came from the area round the machine. When the air shower was switched on, only about 5% of the air came from the surroundings. Airborne microbial contamination of containers is in proportion to: the number of airborne microbes around the machine, the time the container is open, the neck area and the amount of air left within the container. The likely microbial contamination rate can be calculated from a model incorporating these variables. Microbial contamination of containers during BFS manufacturing is normally very low, but by increasing the naturally occurring bacteria in the air of the production rooms by about 100-fold, it was possible to verify the accuracy of this model. The contamination model agrees well with the observation that microbial contamination levels of between 1 in 10(5) and in 10(7) will be found when small containers (< 10 ml) are filled in conventionally ventilated rooms. To achieve similar contamination rates when filling of larger bottles, it is likely that unidirectional flow, or barrier technology will be required.

Air Microbiology↗