Lec 2 Part 1 Factors Affecting Absorption

Question 1

What are the physicochemical factors that affecting percutaneous absorption?

Answer 1

1_partition coefficient
2_molecular size
3_drug concentration
4_ temperature
5_PH

Question 2

What is the partition coefficient?

Answer 2

Is the distribution of chemical compound between two phases.

Question 3

If the drug partitioning coefficient is > 1 it is more hydrophilic (T or F) ?

Answer 3

F more lipophilic

Question 4

If drug partioning coefficient is <1 then the drug is more hydrophilic (T or F)

Answer 4

T

Question 5

In which case of partioning coefficient the drug wont be able to penterate the aqueous barrier of the skin?

Answer 5

If the partioning coefficient is very high

Question 6

In which case of partioning coefficient the druge wont be able to penetrate the lipid barrier?

Answer 6

If the partitioning coefficient is very low.

Question 7

The amount of drug absorbed will increase as the concentration of drug decrease.(T or F)

Answer 7

F

As the concentration of drug increase

Question 8

Higher the concentration of drug in vehicle faster the absorption (T or F)

Answer 8

T

Question 9

The diffusion coefficient decrease as the temperature falls. (T or F)

Answer 9

T

Question 10

Drugs are preferred to be :
1-strong ionized acid /base
2_strong unionized acid/base
3_weak ionized acid/base
4_weak unionized acid /base

Answer 10

4_weak unionized acid/base

Question 11

Only ionized molecules pass readily across lipid membrane (T or F)

Answer 11

F unionized

Question 12

What are the biological factors affecting the absorption?

Answer 12

1_ skin metabolisim
2_skin hydration
3_ skin age
4_skin condition 
5_ regional skin site
6_blood flow

Question 13

As the blood flow increased the amount of time a pentrate remains in the dermis decreased (T or F)

Answer 13

T

Question 14

The high blood flow raises the concentration gradient across the skin (T or F)

Answer 14

T

Question 15

How the regional skin sites affecting the absorption ?

Answer 15

Variation in cutaneous permeability around the body depend on the thickness and nature of the stratum corneum and the density of the skin appendages

Question 16

How we can make the drug effective in the skin only and don’t enter the circulation system ? (Localy drugs)

Answer 16

By using the SOFT DRUGS which are active in the viable epidermis and dermis, skin enzymes bio transform them into inactive metabolites. The active drug therefore dose not enter the circulating system and the pharmacological effect is limitef to the application area.

Question 17

What is the importance of water in absorption of drugs?

Answer 17

Water is natural plasticizer to the skin making its lipid content less rigid(صلابة) by fluidization its crystalline structure. And also hydrates the skin keratin fibers making them softer and more permeable ..where hydrated skin much more permeable than dry skin.

Question 18

Give reason Urea is included in some topical preparations for transdermal drug delivery.

Answer 18

Because the urea act as natural moisturizing factor(NMF)and as a keratolytic agent

Question 19

What is the natural moistureizing factor(NMF)?

Answer 19

It is substance which increase water content of the skin by being able to bind with water to the skin cells.

Question 20

What is the occlusion?

Answer 20

Forming a layer over the skin to prevent evaporation of sweet which accumulates under such layer causing very efficient skin hydration.

Question 21

How can we increase the water content of the skin?

Answer 21

1_By using occlusive vehciles

2_ by using natural moisturizing factors