The Science Journal of the American Association for Respiratory Care

1996 OPEN FORUM Abstracts

EXTRACTABLE LEVEL OF THREE FILTER MATERIALS USING ETHANOL AS A SOLVENT.

Lynda Thomas Goodfellow, MBA, RRT. Randy De Kler MS, RRT, Vijay Deshpande MA, RRT, Joseph L. Rau, Ph.D., RRT, Georgia State University, Atlanta, Georgia.

Purpose: A variety of filter materials are potentially available to collect aerosolized drug in studies of aerosol delivery. This study examined the extractable level of three types of filter materials (cotton, rayon, and glass wool) using ethanol as a solvent. The level of extract is defined as the absorbance of the filter material per unit weight (grams) with the solvent ethanol. It was hypothesized that there would be no significant difference between the mean extractable level of cotton, rayon, and glass wool when ethanol was used as the solvent at a wavelength of 278 nm. Methods: Ten samples each, of cotton, rayon, and glass wool were weighed separately in a Mettler AE 200 balance to ensure comparable size. Each filter sample was then placed in a glass vial with 20 cc's of ethanol and washed for one minute. Next the resulting solution was analyzed by spectrophotometer (Beckman DU 640) at 278 nm. A One-way ANOVA was used to compare the mean absorbance with each filter material. A significance level of 0.01 was used.

Results:

Mean SD N

Material #1 (glass wool).063176 .026388 10

Material #2 (rayon) .207517 .099674 10

Material #3 (cotton) .045402 .017054 10

The F ratio was 21.7137 at 2 and 27 degrees of freedom. (p < 001).

Conclusions: There was a statistically significant difference which suggests that there was a significant difference among the mean extractable levels of filter materials, in relation to the degree of variability within each material group. Based on these results, cotton is a better filter than rayon or glass wool. These results can only be generalized to laboratory research studies investigating in vitro deposition studies when using ethanol as a solvent at a wavelength of 278 nm.

Reference: OF-96-026

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