Stability Testing ofNew Drug Substances and Products 2.1.1. General Information on the stability of the drug substance is an integral part of thesystematic approach to stability evaluation. 2.1.2. Stress Testing Stress testing of the drug substance can help identify the likely degradation products.which can in turn help establish the degradation pathways and the intrinsic stabilityof the molecule and validate the stability indicating power of the analyticalprocedures used. The nature of the stress testing will depend on the individual drugsubstance and the type of drug product involved. Stress testing is likely to be carried out on a single batch of the drug substance. Itshould include the effect of temperatures (in 10°C increments (e.g., 50°C, 60°C, etc.)above that for accelerated testing), humidity(e.g., 75% RH or greater) whereappropriate, oxidation, and photolysis on the drug substance. The testing should alsoevaluate the susceptibility of the drug substance to hydrolysis across a wide range ofpH values when in solution or suspension. Photostability testing should be anintegral part of stress testing. The standard conditions for photostability testing aredescribed in ICH Q1B. Examining degradation products under stress conditions is useful in establishingdegradation pathways and developing and validating suitable analytical procedures.However, it may not be necessary to examine specifically for certain degradationproducts if it has been demonstrated that they are not formed under accelerated orlong term storage conditions. Results from these studies will form an integral part of the information provided toregulatory authorities. 2.1.3. Selection ofBatches Data from formal stability studies should be provided on at least three primarybatches of the drug substance. The batches should be manufactured to a minimum ofpilot scale by the same synthetic route as, and using a method of manufacture andprocedure that simulates the final process to be used for, pro
ASTM G155 Standard Practice forOperating Xenon Arc Lamp Apparatus for Exposure of Materials-
ASTM G155 Standard Practice forOperating Xenon Arc Lamp Apparatus for Exposure of Materials
1. Scope 1.1 This practice is limited to the basic principles andprocedures for operating a xenon arc lamp and water apparatus,on its own, it does not deliver a specifc result. 1.2 It is intended to be used in conjunction with a practice ormethod that defines specific exposure conditions for an appli-cation along with a means to evaluate changes in materialproperties. This practice is intended to reproduce the weathering effects that occur when materials are exposed to sunlight(either direct or through window glass)and moisture ashumidity, rain, or dew in actual use. This practice is limited tothe procedures for obtaining, measuring, and controlling con-ditions of exposure. NoTE 1-A number of exposure procedures are listed in an appendix,however, this practice does not specify the exposure conditions best suitedfor the material to be tested.NoTE 2-Practice Gl51 describes general procedures and performancerequirements to be used when exposing materials in an apparatus that useslaboratory light sources. 1.3 Test specimens are exposed to light from an optically-filtered xenon arc lamp under controlled environmental condi-tions. Different types of optical filters in combination withxenon arc light sources are described. 1.4 Specimen preparation and evaluation of the results arecovered in ASTM methods orspecifcations for specificmaterials. General guidance is given in Practice Gl5l. NOTE 3 General information about methods for determining thechange in properties after exposure and reporting these results is describedin Practice D5870. 1.5 This practice is not intended for corrosion testing of baremetals. 1.6 Units-The values stated in Sl units are to be regardedas standard, No other units of measurement are included in thisstandard. 1.7 This practice is technically similar to the following ISOdocuments:1S0 4892-2,ISO 16474-2.ISO 105-B02.ISO105-B04,ISO 105-B05,ISO 105-B06, and IsO 105-B10. 1.8 This standard does not purport to address all of thesafety concer