Drug Absorption Clinical Pharmacology
Homework is to be presented as a short (50–100-word) paragraph response for each question. The assignment is to be submitted as a Microsoft Word document to the instructor.
Which dosage forms are most appropriate for administering drugs to pediatric patients? Adults? What are the processes involved in disintegration and dissolution? Define pharmacokinetics. Examine the processes of absorption, distribution, metabolism, and excretion, and explain why they occur in this order. What determines the absorption ability of a drug? Define the term pharmacodynamics. Compare the different ways drugs can interact with the body, depending on their mechanism of action. What relationship is there between drug response relationships, serum concentration profiles, and drug manufacturing? How does an adverse effect of a drug occur? What are the causes of some drug-drug interactions?
Drug absorption is determined by the drug’s physicochemical properties, formulation, and route of administration. Dosage forms (eg, tablets, capsules, solutions), consisting of the drug plus other ingredients, are formulated to be given by various routes (eg, oral, buccal, sublingual, rectal, parenteral, topical, inhalational). Regardless of the route of administration, drugs must be in solution to be absorbed. Thus, solid forms (eg, tablets) must be able to disintegrate and disaggregate.
Unless given IV, a drug must cross several semipermeable cell membranes before it reaches systemic circulation. Cell membranes are biological barriers that selectively inhibit the passage of drug molecules. The membranes are composed primarily of a bimolecular lipid matrix, which determines membrane permeability characteristics. Drugs may cross cell membranes by
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Passive diffusion
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Facilitated passive diffusion
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Active transport
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Pinocytosis
Sometimes various globular proteins embedded in the matrix function as receptors and help transport molecules across the membrane.
