ROUTINE PYROGEN TESTING
1 The examination of preparations from large‐scale manufacture for freedom from pyrogens is described. 2 Typical results from the examination of 11. and 0·51. packs of water for injection, glucose‐saline and solution and normal saline solution are presented. 3 Evidence supporting the claim that reduction in the pyrogen levels take place on storage is provided.
SOME OBSERVATIONS ON THE B.P. AND U.S.P. TESTS FOR PYROGENS
THE B.P. and U.S.P. tests for pyrogens depend on the temperature response of rabbits to intravenous administration of the test material. The methods of interpreting the data differ in the two tests but, in each, the material fails to pass the test if it produces a temperature rise greater than that prescribed. The maximum permissible response, in both the B.P. and the U.S.P., is a specified temperature rise, which is not related to any comparison with a standard preparation. Therefore, any factor which affects the magnitude of the temperature response will affect the sensitivity of the tests. The writer has already shown that the degree of restraint imposed on the rabbits, the type of thermometer used, and the frequency of administration of pyrogen, all affect the magnitude of the rabbit’s temperature response to bacterial pyrogenl. Thus when the degree of restraint imposed on the rabbits is severe and clinical thermometers are used, the magnitude of the response to pyrogens is much less than when the degree of restraint is slight and electrical thermometers are used. Furthermore, there is a progressive reduction in response when pyrogen is given repeatedly. The B.P. and U.S.P. specify neither the degree of restraint nor the type of thermometer to be used. Both pharmacopceias permit the repeated use of the same animals. Two questions of practical importance arise from these considerations. The first and more obvious is; how far may the reliability of the tests be affected by failure to take these sources of variation into account? The second, which derives from the different methods of interpreting the data in the B.P. and U.S.P. tests, is; how do the relative efficiencies of the two tests compare when conducted in similar conditions? This paper seeks to provide an answer to these two questions.
Enhancement of surface properties on Low Density Polyethylene packaging films using various fluorination routes
Nowadays, packaging market deployment requires an important attention. Influence of treatment with molecular (F2) or atomic (Fradical dot) fluorine on properties of Low Density Polyethylene (LDPE) films was investigated. The films were treated using direct fluorination conditions with F2 or a specific reagent XeF2, which releases atomic fluorine Fradical dot. Changes of LDPE chemical composition were investigated by FTIR and solid state NMR. Surface morphology was studied by several microscopy techniques (SEM and AFM). Finally to further characterize film properties after treatments, surface energy measurements and electron paramagnetic resonance (EPR) analyses were also carried out. An upper fluorinated layer, which contains mainly high amount of single bondCF2single bond, was formed during the direct fluorination conditions (F2). For the process performed with XeF2, specific groups single bondCHFsingle bond were detected not only on the polymer surface but also in the bulk. The final CHF/CF2 ratio depended on the fluorination route. Treatment with Fradical dot (originated from XeF2 decomposition) resulted in single bondCHFsingle bond groups in bulk prevailing formation whereas F2 formed mainly single bondCF2single bond groups. Regardless to the reactive species, radicals (dangling bonds) appeared during the fluorination and reacted with oxygen during the exposition to air after the treatment. Such a process resulted in oxygenated polar groups formation and consequently in the surface energy increase.