Stability of the active ingredient

A reference substance can be either the formulated test substance suspended in water or the technical or analytical grade active ingredient of the test substance dissolved in a solvent. The reference substance is normally used to fortify field matrices to develop information on the field storage stability of the active ingredient. Reference substances should be prepared at the analytical facility where the matrix samples are to be analyzed. Methods to prepare reference substances for field use will be discussed later. 

Travel fortification samples are a type of field fortification that is usually prepared in the fleld to allow the investigator to determine the stability of the active ingredient on matrices without weathering. Such matrices are fortified and placed immediately in frozen storage. Usually, one set of travel fortification samples for each matrix is prepared for each five sets of weathered fleld fortification samples. The samples are then stored and shipped using the same procedures as all other samples prepared in the fleld. 

The function of citric acid in formulation No. 2 is the stabilization of the active ingredient. The effectiveness was not controlled in this formulation. 

Physical stability of the active ingredient is an important factor that should not be overlooked. The effect of polymorphism on properties of both the active ingredient (e.g., chemical stability, solubility, dissolution rate) and the drug product (e.g., bioavailability) have been extensively studied. Polymorphs or amorphous states of the active ingredient may impact chemical stability as well as dissolution rates, solubility, and bioavailability. This should be studied appropriately. This is discussed further in the sections below. 

These three steps may be repeated to reach the final structure. For example, microcapsules obtained by spray drying of polymer/active solution may be coated by a melted solution. The first encapsulation insures immobilization and stabilization of the active ingredient, while coating allows control of the level of protection and release. 

The stability of the active ingredient. Special storage conditions should be applied to guarantee stability over the treatment period. 

The storage stability of a pesticide formulation depends on the intrinsic stability of the active ingredient, the formulation and the protective function of the packing material. 

Parts of the process likely to have a significant adverse influence on the stability of the active ingredients) (e.g. use of steam in pellet manufacture) should be carried out in an uniform manner from batch to batch. 

For purposes of establishing the identity, quality, potency, purity and stability of the active ingredients and the dosage forms of the drugs whose registration is being requested, the Institute will limit itself to the standards established by the pharmacopeias and their supplements which are officially in effect in the country ... 

To solve formulation problems arising from a limited chemical or physical stability of the active ingredient... 

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