Excipients physicochemical characteristics

Active and key excipients physicochemical characteristics, particle size, purity, batch analysis... 

Comprehensive physicochemical characterization of any raw material is a crucial and multi-phased requirement for the selection and validation of that matter as a constituent of a product or part of the product development process (Morris et al., 1998). Such demand is especially important in the pharmaceutical industry because of the presence of several compounds assembled in a formulation, such as active substances and excipients, which highlights the importance of compatibility among them. Besides, variations in raw materials due to different sources, periods of extraction and various environmental factors may lead to failures in production and/or in the dosage form performance (Morris et al., 1998). Additionally, economic issues are also related to the need for investigating the physicochemical characteristics of raw materials since those features may determine the most adequate and low-cost material for specific procedures and dosage forms. 

The physicochemical characteristics of the components (both drugs as well as excipients) used in dry powders are of significant importance for the performance of the inhalation sys-... 

Besides surface texture, excipient particle size also plays an important role in the fine particle generation as shown by budesonide, where the highest fine particle fraction was obtained with small-sized (<32pm) lactose as the carrier. Additionally, fine particle excipients such as fine lactose or polyethylene glycol were reported to improve the performance of carrier-based protein dry powder aerosols.However, there are some cases where carriers improved total powder emission but reduced the percent of active powders in the aerosol. To be useful carriers, the excipients must be physically stable. The important physicochemical characteristics for drug carrier selection are discussed in Ref.t f... 

In emulsion systems, the existence of two distinct phases (oil and water) results in a distribution of the parabens according to their physicochemical characteristics. This distribution can be influenced by the presence of other ingredients, such as co-solvents and surfactants. Furthermore, these excipients may also affect skin barrier properties. Thus, Dal Pozzo and Pastori (1996) found that permeation of the parabens from two O/W emulsions was higher than expected, based on their data using simple vehicles (described above), and that permeation from the O/W emusions was higher than that from the W/O emulsion. These results were rationalised on the basis of permeant release from the formulation, and it was assumed that the external lipid phase of the W/O emulsion retained the parabens. 

Intravenous immunoglobulin products differ in excipients and physicochemical characteristics. Each may have slightly different profiles of efficacy and adverse reactions. The reported adverse reaction rate varies between 2% and 25% of all infusions, depending on the disease being treated and the patient population. There is a higher incidence rate after a first exposure. Most of the adverse reactions are classified as being of mild-to-moderate intensity [1 , 54, 57", 58"]. In one prospective study in almost 400 patients with immunodeficiency (over 13 000 infusions), the adverse reaction rate was 0.8% none of these events was classified as severe [54 ]. In 38 children there was an adverse reaction rate of 9% of all infusions none was life-threatening [59"]. In 70 patients who received 1085 infusions there was an adverse events rate of 4.3% of all infusions (33% of all patients) none was serious [58"]. In one study of 341 infusions, severe adverse reactions led to discontinuation of therapy in 4% of all treatment courses [53 ]. 

Biopharmaceutic considerations in the design and manufacture of a drug product to deliver the active drug with the desired bioavailability characteristics include 1) the type of drug product (e.g., solution, suspension suppository) 2) the nature of the excipients in the drug product 3) the physicochemical properties of the drug molecule and 4) the route of drug administration. 

By hybridizing mucin and MCC, a novel polymer with a combination of the physicochemical and functional properties characteristic of the two-component polymers was obtained. The new polymer was directly compressible and it possessed mucus membrane protectant. Thus, to produce a novel excipient with membrane-protective, mucoadhesive, and direct compression properties for... 

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