Questions and Answers
What is a significant advantage of transdermal drug delivery systems (TDDSs)?
Which of the following factors does NOT affect drug absorption through the skin?
Which drug is NOT commonly administered via transdermal patches?
What distinguishes membrane-controlled systems from monolithic TDDSs?
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In the context of TDDSs, what is the role of percutaneous absorption enhancers?
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Which factor limits the suitability of drugs for transdermal delivery?
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What is the primary purpose of the Franz diffusion cell in TDDS research?
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Which statement about the first TDDS approved by the FDA is true?
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Study Notes
Overview of Transdermal Drug Delivery Systems (TDDSs)
- TDDSs, or transdermal patches, deliver medication through the skin into the bloodstream for systemic effects.
- First TDDS approved by the FDA was Transderm Scop (Baxter) in 1979 for motion sickness.
Mechanism and Advantages
- Bypasses first-pass metabolism in the liver, potentially reducing side effects and enhancing drug efficacy.
- Drug absorption is influenced by drug properties such as molecular weight, lipid and aqueous solubility, and skin hydration.
Types of TDDSs
- Monolithic systems: Feature a drug matrix layer controlling drug release between the backing and frontal layers.
- Membrane-controlled systems: Contain a drug reservoir, rate-controlling membrane, and backing, adhesive, and protective layers.
Drug Delivery and Absorption Enhancers
- Percutaneous absorption enhancers (chemical and physical) can improve drug delivery through the skin.
- The Franz diffusion cell is employed to study release rates from TDDSs and various formulations.
Benefits of TDDSs
- Non-invasive administration of medications.
- Provide extended therapy with a single application, which is beneficial for chronic conditions.
- Easily identifiable in emergencies due to their visible nature.
Limitations
- Suitable only for potent drugs, as skin permeability limits many medications.
- Only small doses can be efficiently delivered through TDDSs.
Common Drugs Administered via TDDSs
- Scopolamine: Used for motion sickness.
- Nitroglycerin: Used for angina; TDDSs (Minitran, Nitro-Dur) provide controlled delivery for 24 hours. Recommended dosing involves 12-14 hours "patch on" and 10-12 hours "patch off" due to tolerance issues.
- Clonidine: Treats hypertension; available in a four-layer patch (Catapres-TTS) effective for up to 7 days.
- Estradiol: Administered for hormonal therapy.
- Testosterone: Delivered for male hormone replacement.
- Methylphenidate: Used for treating attention deficit hyperactivity disorder (ADHD).
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Description
This quiz provides an in-depth overview of Transdermal Drug Delivery Systems (TDDSs), including their purpose, key features, and historical context. Learn about the benefits of using transdermal patches, such as bypassing first-pass metabolism and enhancing drug efficacy. Test your knowledge on FDA-approved TDDSs and their applications.