Pharmacology: Lipid Nature of Drugs and Skin Permeation

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Questions and Answers

What is the main reason why drug transport through skin is possible?

Lipoid nature of the intercellular medium

Which transport route involves the movement of drugs between corneocytes?

Intercellular route

What is the primary lipid component of the intercellular medium?

Phospholipids

Which route of transport is suitable for small molecules only?

Intercellular route Signup and view all the answers

What is the primary function of sebaceous glands in skin transport?

To provide a shunt route for drugs Signup and view all the answers

What is the term for transport through hair follicles and sebaceous glands?

Trans-appendageal transport Signup and view all the answers

Which route of transport involves the movement of drugs through corneocytes?

Transcellular route Signup and view all the answers

What is the most abundant route of drug transport through the skin?

Stratum corneum permeation Signup and view all the answers

What is the primary obstacle in drug permeation through the skin?

Passing through the stratum corneum Signup and view all the answers

What is transappendageal transport?

Drug transport through the skin appendages Signup and view all the answers

Which type of transport is also known as shunt route transport?

Transappendageal transport Signup and view all the answers

What are the skin appendages responsible for transappendageal transport?

Sweat glands, hair follicles, and sebaceous glands Signup and view all the answers

What is the term for the movement of a drug within a membrane composed of more than one layer?

Penetration Signup and view all the answers

What is the advantage of transappendageal transport?

It is a fast pathway with no barrier effect of stratum corneum Signup and view all the answers

What is the unit of drug permeation through a membrane?

cm/min Signup and view all the answers

Which of the following is an example of transcellular transport?

Intracellular and intercellular transport Signup and view all the answers

Why is the sweet gland route not influential to drug transport?

It is a rare route Signup and view all the answers

What is the disadvantage of transappendageal transport?

It is a rare route Signup and view all the answers

What is the term for the routes of drug permeation through the skin?

Skin permeation pathways Signup and view all the answers

What happens to the drug molecules after they enter the sweat glands?

They are transported through the sweat ducts Signup and view all the answers

Which type of transport is considered EASY and FAST but LESS COMMON?

Transappendageal transport Signup and view all the answers

What is the role of the blood capillaries surrounding the sweat glands and sebaceous glands?

They absorb the drug molecules Signup and view all the answers

What is the name of the outermost layer of the skin that is a significant barrier to drug permeation?

Stratum corneum Signup and view all the answers

What happens to the drug molecules after they enter the hair follicles and sebaceous glands?

They are transported through the sebaceous sacs Signup and view all the answers

Study Notes

Skin Permeation Pathways

Lipoid nature of drugs allows them to pass easily through sweet glands, hair follicles, and sebaceous glands
Targeted effect is needed for shunt transport through hair follicle and sebaceous glands routes
Skin permeation pathways refer to the routes of drug permeation through the skin

Transport Through Stratum Corneum

Most abundant route of drug transport through the skin
Two main routes:
- Intercellular route: drug moves between corneocytes till it reaches viable epidermis
- Transcellular route: drug moves through corneocytes till it reaches viable epidermis

Intercellular Route

Intercellular medium is lipid in nature, composed of phospholipids, ceramide, and cholesterol
Suitable for small molecules with a molecular weight of less than 400 dalton
Permeation coefficient (P) expresses the rate of drug permeation through the membrane

Transappendageal Transport (Shunt Route)

Drug transport through skin appendages (sweet glands, hair follicles, and sebaceous glands)
Easy and fast pathway, but less common
Advantage: no barrier effect of stratum corneum, but disadvantage: rare route with insignificant contribution to drug transport

Transport Through Sweet Glands and Hair Follicles

Transport through sweet glands:
- Drug molecules enter sweet openings
- Travel through sweet ducts
- Reach sweet glands
- Absorbed by blood capillaries surrounding sweet glands
Transport through hair follicles and sebaceous glands:
- Drug molecules enter hair openings
- Travel through sebaceous sacs
- Reach sebaceous glands
- Absorbed by blood capillaries surrounding sebaceous glands