24 Questions
What is the primary purpose of adding excipients to pharmaceutical formulations?
To improve the stability of the active pharmaceutical ingredients in the dosage form
What can occur when excipients interact with active pharmaceutical ingredients?
Decomposition of the drug substance
Which type of interaction between API and excipients does not involve the formation or breakage of chemical bonds?
Physical interaction
What is a potential consequence of physical interactions between API and excipients?
Changes in the dissolution rate of the API
What is the term for the ability of excipients to modulate the bioavailability of active pharmaceutical ingredients?
Bioavailability modulation
Which of the following is NOT a function of excipients in pharmaceutical formulations?
Enhancing the efficacy of the API
What can excipients contain that may interact with active pharmaceutical ingredients?
All of the above
What is the term for the ability of excipients to improve the solubility of active pharmaceutical ingredients?
Solubility enhancement
What is the primary function of cyclodextrins in drug-excipient interactions?
To form inclusion complexes with the drug, improving its solubility
What is the purpose of adding lubricants like magnesium stearate during tablet formulation?
To reduce friction between particles, improving tablet flow properties
Which type of interaction between a drug and an excipient can help control the polymorphic form of the drug?
Solid-state interactions
What is the potential detrimental effect of certain excipients on drug absorption in the gastrointestinal tract?
Interference with drug absorption due to the formation of insoluble complexes
What is the role of surfactants like polysorbate 80 in drug-excipient interactions?
To form micelles in aqueous solutions, enhancing the dispersion and absorption of lipophilic drugs
What is the purpose of using cyclodextrins in drug formulation?
To enhance the solubility of the drug
What is the potential beneficial effect of the interaction between a drug and an excipient like polyethylene glycol?
Control of the polymorphic form of the drug
What is the primary purpose of tablet formulation in pharmaceutical compression?
To improve the flow properties of the tablet and prevent sticking to the tablet punches
What can excessive use of certain excipients or lubricants, such as magnesium stearate, lead to during tablet formulation?
Poor tablet disintegration and dissolution, impacting drug release
What type of interaction involves a chemical reaction between drugs and excipients or drugs and impurities/residues present in the excipients?
Chemical interaction
What is an example of a chemical interaction between a drug and an excipient?
Primary amine group of chlorpromazine reacting with glycosidic hydroxyl group of reducing sugar dextrose
What can residues in excipients, such as povidone and crospovidone, lead to?
Formation of the N-oxide degradation product
What is an example of an interaction between a drug and an excipient residue/impurity?
Raloxifene interacting with peroxide residues in povidone
What type of interaction occurs between two or more excipients in a drug molecule?
Excipient-Excipient interaction
What can poor tablet disintegration and dissolution lead to during tablet formulation?
Impacted drug release
What is a consequence of chemical interactions between drugs and excipients?
Formation of degradation products
Study Notes
Mechanism of Drug Excipient Interaction
- Excipients are inactive substances added to pharmaceutical formulations to serve various purposes, including improvement of API stability, modulation of bioavailability, and maintenance of pH and rheology.
Beneficial Effects of Drug Excipient Interaction
- Complexation with cyclodextrins (e.g., hydroxypropyl beta-cyclodextrin) can improve drug solubility by encapsulating the hydrophobic drug molecule within the hydrophobic cavity of the cyclodextrin.
- Solid-state interactions with stabilizing polymers or crystallization inhibitors (e.g., PEG) can help control the polymorphic form of the drug, ensuring physical stability and preventing unwanted crystal transformations.
- Micellar solubilization with surfactants (e.g., polysorbate 80) can enhance the dispersion and absorption of lipophilic drugs.
- Tableting interactions with lubricants (e.g., magnesium stearate) can reduce friction between particles, improving tablet flow properties and preventing sticking to the tablet punches.
Detrimental Effects of Drug Excipient Interaction
- Interference with drug absorption can occur when certain excipients in oral formulations form insoluble complexes with the drug, reducing drug dissolution and absorption.
Classification of Drug Excipient Interactions
- Physical interactions: do not involve formation or breakage of chemical bonds in the drug molecular structure, but can affect dissolution rate, dosage uniformity, organoleptic properties, polymorphic forms, crystallization behavior, or drug-release and stability.
- Chemical interactions: involve chemical reactions between drugs and excipients or impurities/residues present in the excipients, leading to the formation of degradation products and changes in the integrity of the substance.
Examples of Chemical Interactions
- Maillard reaction between primary amine groups of chlorpromazine and glycosidic hydroxyl groups of reducing sugar dextrose, leading to the formation of imine and finally Amidori compounds.
- Precipitation of drugs such as neomycin and polymixin due to interaction with suspending agents like sodium alginate.
- Enhanced formation of N-oxide degradation product of raloxifene due to peroxide residues in povidone and crospovidone.
Excipients-Excipients Interaction
- Interaction between two or more excipients in a drug molecule, which can affect the overall stability, efficacy, or safety of the pharmaceutical product.
Explore the mechanisms of drug-exipient interactions, including complexation for enhanced solubility and solid-state interactions for polymorphic control. Learn about the beneficial effects of these interactions.
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