Toical Drug Delivery W5 Flashcards
What is the largest organ in the body?
The skin
What is the weight of the skin?
2.5 kg
What are the protective functions of the skin?
Protects internal body structures, limits entry of noxious chemicals, stabilizes body temperature and blood pressure
What is the role of melanocytes in the skin?
Produce skin pigment protein (melanin)
What is the stratum corneum?
The outermost layer of the epidermis, consisting of keratin-rich dead cells
True or False: The stratum corneum is metabolically active.
False
What is the thickness range of the stratum corneum on palmar and plantar surfaces?
200-800 microns
What are the main components of the dermis?
- Collagen (70%)
- Elastin
- Fibrillin
What are eccrine sweat glands responsible for?
Body temperature homeostasis and emotional response
What is the function of sebaceous glands?
Produce a lipid-rich secretion called sebum
What is the hypodermis?
Subcutaneous fat layer that acts as a mechanical protector, thermal insulator, and energy store
Fill in the blank: Topical drug delivery involves the delivery of a medicament to the _______ or mucous membrane.
[skin]
What is the primary barrier to drug absorption in topical delivery?
Stratum corneum
What factors determine the rate of drug absorption across the skin?
- Concentration of drug applied
- Diffusion coefficient of drug
- Solute partition coefficient
What equation predicts the rate of drug transport across the skin?
J = D * P * (ΔC / d)
How can the rate of drug absorption across the skin be increased?
- Increase concentration of drug at skin surface
- Use supersaturated drug formulations
- Increase drug diffusion coefficient
What is the purpose of a Franz diffusion cell?
To measure the rate of drug transport across the skin
What does the Potts and Guy equation predict?
Drug transport rate based on molecular size and hydrophobicity
What is the transdermal drug delivery market worth as of the year 2000?
$2 billion per year
What are the two main categories of transdermal skin patches?
- Monolith (matrix) system
- Rate-limiting membrane system
What is the significance of microneedle devices in drug delivery?
They allow large drug molecules like peptides/proteins to penetrate the skin without reaching nerve fibers
What are the key advantages of transdermal patches?
- Avoids first-pass metabolism
- Consistent site of absorption
- Can stop dosing by removing the patch
Fill in the blank: Hydrated skin is generally more _______ to drug.
[permeable]
What formulation techniques can enhance transdermal drug delivery?
- Use of penetration enhancers
- Ointments that restrict water loss
- Supersaturated drug concentrations
What is the role of skin hydration in transdermal drug transport?
Looser packing of SC lipids allows for less restrictive paths for drug diffusion
True or False: All drugs can be effectively delivered across the skin.
False
What is the function of hair follicles in drug delivery?
May increase permeability for certain drugs, especially hydrophilic ones
What is the primary function of the stratum corneum?
Defense against external factors
The stratum corneum has much less enzymatic activity.
What technology utilizes tiny, invisible needles that penetrate the epidermis?
Microneedle Devices
These devices do not reach the nerve fibers.
What is the purpose of iontophoresis?
Driving of charged molecules through the skin using low electrical currents
Typically uses a current of 0.5mA/cm².
Which drug is used for hyperhidrosis?
Glycopyrronium bromide
It is delivered using iontophoresis.
What are the two types of drugs mentioned in relation to iontophoresis?
Cationic drug and Anionic drug
These terms refer to the charge of the drugs used in the process.
What factors determine drug penetration of the stratum corneum?
Many drug and formulation factors
These factors include physicochemical parameters.
What is an important consideration for many topical formulations?
Patient acceptability
This affects the choice of formulation.
Fill in the blank: Topical delivery can be used for _______ or systemic delivery.
[local]
Local delivery is a significant aspect of topical formulations.
What are the types of formulations mentioned for local delivery?
Many formulation types exist
This is especially true for local delivery.
Which chapters of essential readings focus on transdermal drug delivery?
Chapter 38 of Aulton’s Pharmaceutics (3rd Edition) and Chapter 9.5 of Physicochemical Principles of Pharmacy (4th Edition)
These chapters provide detailed information on transdermal delivery.
