Pharmaceutics

Preservative interactions with formulation components and containers

The adequacy with which a formulated medicine is protected from spoilage by the use of a preservative cannot easily be predicted from a study of the activity of the preservative in simple aqueous solutions. A person with limited knowledge of pharmaceutical microbiology might, for example, expect that it would be possible to confirm that a …

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Selection and use of preservatives

The antimicrobial chemicals commonly used as preservatives in medicines are will be a stand alone article. The properties that are normally required in such a preservative include the following: a broad spectrum of antimicrobial activity covering Gram-positive and Gram-negative bacteria, yeasts and moulds, and no vulnerability to resistance development; low toxicity for humans, enabling it …

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Factors influencing the growth of spoilage organisms

In addition to water activity, which was considered earlier in this chapter, factors influencing the rate and extent of growth of a contaminant within a pharmaceutical raw material or manufactured medicine include: nutrient availability; temperature; pH; redox potential; and the presence and concentration of antimicrobial chemicals. Microorganisms differ enormously in their metabolic capabilities. Some, such …

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Sources and types of contaminating organisms in pharmaceuticals

Microbial contamination of medicines arises from three principal sources: the raw materials, including water, from which the product is manufactured; the manufacturing environment, including thenatmosphere, equipment and work surfaces; and manufacturing personnel. The relative contributions of these three sources vary depending on the type of product in question. It is a known fact that raw …

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Products and materials vulnerable to spoilage

Spoilage, in the sense of detectable physical or chemical change within a pharmaceutical product, nearly always follows growth and reproduction of the contaminating organisms. The pharmacopoeial and regulatory limits for the maximum permissible numbers of microorganisms in manufactured products or raw materials are typically not more than 100–1000 colony-forming units per millilitre or gram depending …

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The need to protect medicines against microbial spoilage

The need to protect foods against microbial spoilage is well appreciated because microbial growth results in obvious signs of deterioration. However, there is a much lower level of awareness among members of the general public of the need to similarly protect cosmetics, toiletries and medicines. Although most medicines present a less favourable environment for microbial …

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Pharmacokinetics of drugs and drug substances

Pharmacology can be divided into two disciplines. These are: Pharmacokinetics: the way the body affects the drug with time, i.e. the factors that determine its absorption, distribution, metabolism and excretion. Pharmacodynamics: the biological effect of the drug on the body. 1. Administration Topical Topical drugs are applied where they are needed, giving them the advantage that …

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Drug factors in dosage form design

Each type of dosage form requires careful study of the physical and chemical properties of drug substances to achieve a stable, efficacious product. These properties, such as dissolution, crystal size and polymorphic form, solid-state stability and drug– additive interaction, can have profound effects on the physiological availability and physical and chemicals tability of the drug. Through …

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