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Questions and Answers
What is a significant disadvantage of electroporation in drug delivery?
What is a significant disadvantage of electroporation in drug delivery?
Which type of microneedle involves the drug dissolving within the body after administration?
Which type of microneedle involves the drug dissolving within the body after administration?
What is a primary requirement for effective thermal ablation of the stratum corneum?
What is a primary requirement for effective thermal ablation of the stratum corneum?
How do microneedles facilitate drug delivery compared to traditional methods?
How do microneedles facilitate drug delivery compared to traditional methods?
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What is the significance of micron-scale defects created by thermal ablation?
What is the significance of micron-scale defects created by thermal ablation?
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Which of the following statements about transdermal drug delivery systems is true?
Which of the following statements about transdermal drug delivery systems is true?
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What is a primary advantage of transdermal drug delivery systems compared to traditional delivery methods?
What is a primary advantage of transdermal drug delivery systems compared to traditional delivery methods?
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Which layer of skin poses the greatest barrier to transdermal drug delivery?
Which layer of skin poses the greatest barrier to transdermal drug delivery?
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Transdermal drug delivery systems are particularly suitable for which type of treatment?
Transdermal drug delivery systems are particularly suitable for which type of treatment?
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Which of the following substances is likely to face the most difficulty when attempting transdermal delivery?
Which of the following substances is likely to face the most difficulty when attempting transdermal delivery?
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What role does the dermis play in the context of transdermal drug delivery systems?
What role does the dermis play in the context of transdermal drug delivery systems?
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What is a significant limitation faced by transdermal drug delivery systems?
What is a significant limitation faced by transdermal drug delivery systems?
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How does transdermal drug delivery bypass the complications associated with gastrointestinal administration?
How does transdermal drug delivery bypass the complications associated with gastrointestinal administration?
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What is the primary mechanism through which laser thermal ablation enhances drug permeation in the skin?
What is the primary mechanism through which laser thermal ablation enhances drug permeation in the skin?
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Which factor is NOT relevant in determining the penetrative ability of drugs through the skin?
Which factor is NOT relevant in determining the penetrative ability of drugs through the skin?
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Which characteristic must drugs possess to enhance transdermal delivery using chemical enhancers?
Which characteristic must drugs possess to enhance transdermal delivery using chemical enhancers?
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What distinguishes vesicles such as liposomes from other colloidal systems?
What distinguishes vesicles such as liposomes from other colloidal systems?
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Which of the following statements about liposomes is incorrect?
Which of the following statements about liposomes is incorrect?
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When are multilayer vesicles formed?
When are multilayer vesicles formed?
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What is the main role of chemical enhancers in transdermal drug delivery systems?
What is the main role of chemical enhancers in transdermal drug delivery systems?
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Which type of drug delivery system would most likely utilize ethosomes?
Which type of drug delivery system would most likely utilize ethosomes?
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What is the primary component used in the formation of liposomes?
What is the primary component used in the formation of liposomes?
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Which property is characteristic of transfersomes compared to traditional liposomes?
Which property is characteristic of transfersomes compared to traditional liposomes?
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What is the primary issue addressed by Transdermal Drug Delivery Systems (TDDS)?
What is the primary issue addressed by Transdermal Drug Delivery Systems (TDDS)?
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In TDDS, which pathway is primarily used for substances with small molecular weights?
In TDDS, which pathway is primarily used for substances with small molecular weights?
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Which of the following methods is classified as active transdermal delivery?
Which of the following methods is classified as active transdermal delivery?
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What is the function of iontophoresis in transdermal drug delivery?
What is the function of iontophoresis in transdermal drug delivery?
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Which of the following best describes the barrier effect in TDDS?
Which of the following best describes the barrier effect in TDDS?
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What type of electrical current is applied during iontophoresis?
What type of electrical current is applied during iontophoresis?
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Which of the following is NOT a factor affecting drug delivery in TDDS?
Which of the following is NOT a factor affecting drug delivery in TDDS?
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What characteristic of the skin structure primarily complicates drug delivery?
What characteristic of the skin structure primarily complicates drug delivery?
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What advantage does active transdermal delivery offer over conventional methods?
What advantage does active transdermal delivery offer over conventional methods?
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What type of substances can iontophoresis facilitate through the skin?
What type of substances can iontophoresis facilitate through the skin?
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What is the primary feature that distinguishes transfersomes from regular liposomes?
What is the primary feature that distinguishes transfersomes from regular liposomes?
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Which statement about ethosomes is accurate?
Which statement about ethosomes is accurate?
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How do polymeric nanoparticles improve drug delivery?
How do polymeric nanoparticles improve drug delivery?
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What characteristic of ethosomes contributes to their increased drug penetration capability?
What characteristic of ethosomes contributes to their increased drug penetration capability?
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What is one limitation of liposomes regarding drug absorption?
What is one limitation of liposomes regarding drug absorption?
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What molecular weight (MW) of drugs can transfersomes effectively deliver through the skin?
What molecular weight (MW) of drugs can transfersomes effectively deliver through the skin?
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What is a key disadvantage of the liposome structure?
What is a key disadvantage of the liposome structure?
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Which characteristic of nanoparticle (NP) drug administration leads to fewer side effects?
Which characteristic of nanoparticle (NP) drug administration leads to fewer side effects?
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What effect do single-chain surfactants have on transfersomes?
What effect do single-chain surfactants have on transfersomes?
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What type of molecular structures comprise ethosomes?
What type of molecular structures comprise ethosomes?
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Flashcards
Transdermal drug delivery
Transdermal drug delivery
A drug delivery method that uses the skin's intact surface to deliver medicine directly into the bloodstream.
First-pass metabolism avoidance
First-pass metabolism avoidance
Medicines delivered through the skin bypass the digestive system, reducing breakdown and improving absorption.
Stratum corneum barrier
Stratum corneum barrier
The skin's outermost layer, the stratum corneum, acts as a barrier against external substances.
TDDDs for chronic conditions
TDDDs for chronic conditions
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Skin layers as barriers
Skin layers as barriers
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TDDDs convenience and safety
TDDDs convenience and safety
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Controlled drug release in TDDDs
Controlled drug release in TDDDs
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TDDDs potential and challenges
TDDDs potential and challenges
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Chemical enhancers in TDDDs
Chemical enhancers in TDDDs
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Low molecular weight (MW) in TDDDs
Low molecular weight (MW) in TDDDs
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Vesicles for Transdermal delivery
Vesicles for Transdermal delivery
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Liposomes
Liposomes
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Thermal ablation
Thermal ablation
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Laser thermal Ablation
Laser thermal Ablation
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Drug solubility in TDDDs
Drug solubility in TDDDs
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Drug lipophilicity and hydrophilicity in TDDDs
Drug lipophilicity and hydrophilicity in TDDDs
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Drug half-life in TDDDs
Drug half-life in TDDDs
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What is the barrier effect in transdermal drug delivery?
What is the barrier effect in transdermal drug delivery?
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What are Transdermal Drug Delivery Systems (TDDDs)?
What are Transdermal Drug Delivery Systems (TDDDs)?
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How do small molecules get through the skin?
How do small molecules get through the skin?
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How do larger molecules pass through the skin barrier?
How do larger molecules pass through the skin barrier?
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What is iontophoresis?
What is iontophoresis?
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How does iontophoresis enhance drug delivery?
How does iontophoresis enhance drug delivery?
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What types of medications can be delivered using iontophoresis?
What types of medications can be delivered using iontophoresis?
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What are the different layers of the skin?
What are the different layers of the skin?
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What are the other challenges for TDDDs beyond the stratum corneum?
What are the other challenges for TDDDs beyond the stratum corneum?
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What are active drug delivery systems?
What are active drug delivery systems?
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Microneedles
Microneedles
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Dissolving microneedles
Dissolving microneedles
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Electroporation
Electroporation
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Stratum corneum
Stratum corneum
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Liposomes: Hydrophilic and Hydrophobic
Liposomes: Hydrophilic and Hydrophobic
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Liposomes: Limited Penetration
Liposomes: Limited Penetration
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Transfersomes: Deformable Liposomes
Transfersomes: Deformable Liposomes
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Transfersomes: Surfactant Effect
Transfersomes: Surfactant Effect
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Ethosomes: Alcohol-rich Liposomes
Ethosomes: Alcohol-rich Liposomes
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Ethosomes: Enhanced Skin Penetration
Ethosomes: Enhanced Skin Penetration
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Nanoparticles: Tiny Carriers
Nanoparticles: Tiny Carriers
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Nanoparticles: Classification
Nanoparticles: Classification
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Nanoparticles: Targeted Drug Delivery
Nanoparticles: Targeted Drug Delivery
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Nanoparticles: Improved Drug Performance
Nanoparticles: Improved Drug Performance
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Study Notes
Transdermal Drug Delivery Systems (TDDDs)
- Transdermal delivery is the delivery of a drug through intact skin to reach systemic circulation in sufficient quantities for therapeutic benefit.
- TDDDs are ideally suited for chronic conditions requiring continuous treatment.
- Antidiabetic agents are a common target for transdermal research.
- Conventional drug delivery systems (DDS) have limitations in drug delivery.
- Novel DDS are newer delivery systems, which overcome some of the limitations of conventional systems.
Drug Delivery Systems (DDS)
- DDS is a broad term referring to physicochemical technologies that control drug delivery and release into cells, tissues, and organs, thus improving drug efficacy.
Iontophoresis
- Iontophoresis is a physical method for drug delivery.
- Cationic or neutral therapeutic agents are placed under an anode, and anionic agents are placed under a cathode.
- Applying a low voltage and current density repels ions into and through the skin.
- Iontophoresis enhances skin penetration and increases drug release rates of poorly absorbed drugs.
Sonophoresis
- Ultrasound frequencies improve transdermal drug delivery by creating an aqueous path through the perturbed skin layers through cavitation.
- The drug is mixed with a specific coupler (e.g., gel or cream) to transmit ultrasonic waves to the skin.
- Ultrasound increases the local skin temperature, enhancing drug penetration.
- Limitations exist in the precise understanding of sonic penetration mechanisms, device availability, and potential side effects (e.g., burns).
Electroporation
- Electroporation involves applying high-voltage electric pulses to the skin to create temporary pores, enhancing permeability and drug diffusion.
- Applying pulses in a safe manner using electrodes ensures successful drug delivery.
- Low-molecular-weight drugs are suitable for this technique, along with high-molecular-weight drugs (e.g., peptides and oligonucleotides).
- Limitations include smaller delivery loads, issues like cell death, heating-induced damage, and denaturation of therapeutic biomolecules.
Microneedles
- Microneedles are micron-sized needles that pierce the skin's superficial layer.
- Drug diffusion occurs across the epidermal layer.
- Microneedles directly deliver drugs to the blood capillary region for absorption.
- Solid, drug-coated, dissolving, and hydrogel-forming microneedles are different types of microneedle tools.
- Microneedle patches combined with diverse patch types provide various drug delivery methods as a whole.
Thermal Ablation
- Thermal ablation, also known as thermophoresis, uses localized heat to selectively disrupt stratum corneum structure.
- Microchannels created in the skin enhance drug delivery.
- Ablation requires high temperatures (above 100°C) for keratin vaporization.
- Short thermal exposure durations minimize potential side effects like pain, bleeding, and infection.
- Thermal ablation is induced by lasers and radiofrequency methods.
Transdermal Drug Delivery Using Chemical Enhancers (Passive Delivery)
- This involves using chemicals to increase drug penetration through the skin.
- Drugs should have low molecular weights (<1 kDa), affinity to lipophilic and hydrophilic phases, short half-lives, and minimal skin irritation.
- Various factors impact drug penetration, including species differences, skin characteristics, application, and physical properties of the penetrant.
- Novel technologies, such as chemical enhancers, solubility increasing agents, and the design of specialized formulations, are used to improve delivery.
- Technologies using formulations like microemulsions, micro- and nano-droplet systems and vesicles are utilized to improve drug distribution.
Vesicles
- Vesicles are colloidal particles containing water and amphiphilic molecules arranged in bilayers (e.g., liposomes, transfersomes, ethosomes).
- Vesicles can carry water-soluble and fat-soluble drugs for transdermal absorption and sustained release.
Liposomes
- Liposomes are circular vesicles formed from one or more phospholipid bilayers separating an aqueous medium.
- Phospholipids form a bilayer because of their hydrophobic tails and hydrophilic heads (polar groups).
- They are both hydrophilic and hydrophobic allowing encapsulation of fat and water soluble substances.
- Limitations involve drug retention on the skin's surface, minimizing drug absorption, and maintaining stability of formulations.
Transfersomes
- Transfersomes are highly deformable, elastic, flexible liposomes.
- Surfactants' addition enhances deformability, enabling penetration of skin pores.
- Transfersomes have a higher penetration capability than liposomes.
Ethosomes
- Ethosomes are formed from phospholipids, alcohols, and water.
- Higher alcohol concentrations improve flexibility and fluidity, leading to improved drug penetration.
- Ethosomes enable deep penetration or direct skin delivery of drugs.
Polymeric Nanoparticles
- Nanoparticles (NPs) are nanocarriers with sizes between 1 and 1000 nm.
- Polymeric NPs provide targeted and controlled drug release, increasing bioavailability and reducing toxicity.
- NPs improve drug delivery by conferring protection, controlling degradation, and promoting consistent drug release.
Nanoemulsion
- Nanoemulsions are emulsions with droplet sizes between 20 and 500 nm.
- They offer exceptional properties, such as robust stability and tunable rheology.
- Nanoemulsions are used in topical and other delivery methods.
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Description
Explore the principles and methodologies of Transdermal Drug Delivery Systems (TDDDs). Understand their advantages for chronic conditions and their role in drug delivery, including the mechanisms like iontophoresis. Learn about novel drug delivery systems in comparison to conventional ones.