Stabilization of active ingredients

A specified area of filter must be soaked in a specified volume of product for a designated time. The accelerated stability of active ingredients at 40-60°C for 60 days must be established prior to the selection of a filter for a particular purpose. The extent of damage, and the nature and quantity of extractables and their potency have to be evaluated. 

The chemical stability of active ingredients incorporated into ointments or creams is frequently dependent on the namre of the ointment... 

Table 112. Stabilization of active ingredients with povidone ...

Insecticide efficacy, the stability of active ingredients, and programmed release of active ingredients from the vehicle/devicc are the most important characteristics controlled for when pesticides are formulated (Krcnek and Rhode, 1988). Environmental Protection Agency (EPA) registration does not always require percutaneous absorp-... 

Table 2-1 lists the headings under which information should be provided in Part II, according to the Notice for Applicants. NMR methods are most likely to appear in Parts lie, HE and IIF which describe respectively the control of starting materials, control of finished product and stability of active ingredient and finished product. As a general rule, any analytical methods should be described in sufficient detail to enable the procedures to be repeated if necessary, for example, by an official laboratory. 

Chemical suppHers include basic manufacturers of active ingredients, formulators, and distribution or service industries. The relative importance of each depends greatly upon the industry being suppHed. In many instances, the vendor may supply a number of performance chemicals (eg, corrosion control agents or stabilizers) in addition to the antimicrobial agent. 

The therapeutically inactive ingredients in ophthalmic solution and suspension dosage forms are necessary to perform one or more of the following functions adjust concentration and tonicity, buffer and adjust pH, stabilize the active ingredients against decomposition, increase solubility, impart viscosity, and act as solvent. The use of unnecessary ingredients is to be avoided, and the use of ingredients solely to impart a color, odor, or flavor is prohibited. 

For many botanical preparations, there are often uncertainties in the identity of the plant species and/or consistency of botanical raw materials. Complicated manufacturing processes add further possible variation to the drug substance and final products. While most contamination problems unique to botanicals are resolvable, purity/potency and stability are more difficult technical issues, without knowing the identity of active ingredients. 

Topical medications usually consist of active ingredients incorporated in a vehicle that facilitates cutaneous application. Important considerations in vehicle selection include the solubility of the active agent in the vehicle the rate of release of the agent from the vehicle the ability of the vehicle to hydrate the stratum corneum, thus enhancing penetration the stability of the therapeutic agent in the vehicle and interactions, chemical and physical, of the vehicle, stratum corneum, and active agent. 

Catalyst-supporting materials are used to immobilize catalysts and to eliminate separation processes. The reasons to use a catalyst support include (1) to increase the surface area of the catalyst so the reactant can contact the active species easily due to a higher per unit mass of active ingredients (2) to stabilize the catalyst against agglomeration and coalescence (fuse or unite), usually referred to as a thermal stabilization (3) to decrease the density of the catalyst and (4) to eliminate the separation of catalysts from products. Catalyst-supporting materials are frequently porous, which means that most of the active catalysts are located inside the physical boundary of the catalyst particles. These materials include granular, powder, colloidal, coprecipitated, extruded, pelleted, and spherical materials. Three solids widely used as catalyst supports are activated carbon, silica gel, and alumina ... 

Comparative studies may also be useful in evaluating the relative stability of commercial formulations of the same drug from different suppliers. In these cases, the cause(s) of differences in stability may be difficult to determine since different sources of active ingredient and different excipients may all be variables that affect stability. 

Polymeric vesicles, or polymersomes, are of interest for the encapsulation and delivery of active ingredients. They offer enhanced stability and lower permeability compared to lipid vesicles, and the versatility of synthetic polymer chemistry provides the ability to tune properties such as membrane thickness, surface... 

The FDA requests that, for NDA/ANDA products, one batch of each strength be manufactured from each listed source of active ingredient. Three months of accelerated stability data, including comparative dissolution, should be available for inspection. 

Stability tests of active ingredients and finished products (7/1988) III... 

The combination of shear and impact action is sufficient to break the typically small crystals of active Ingredients to desired size and the high shear will activate suspension agents adequately for desired stability. As compared to the older ball mill or Attritors, their action has more impact and pulverization effects than a small media mill. 

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