L7 - Topical products

Question 1

The 4 types of topical formulations are there?

Answer 1

Cream, lotion, ointment and gels

Question 2

Selection of topical excipients - what factors?

Answer 2

FDA safe, improve solubility, release, permeation and aesthetics

Question 3

Common topical excipients

Answer 3

solvents, cosolvents, emollients, permeation enhancers, antioxidants, buffers, emulsifiers and antimicrobials

Question 4

What are ointments?

Answer 4

Semisolid, greasy, less preferred by patients, occlusive, prevent water loss, act as emollient

Question 5

What are the 5 ointment bases? Explain a few facts of each

Answer 5

1. Hydrocarbon bases: mix of hard/soft paraffin, water difficult to incorporate
2. Fats and oils: non volitile, needs antioxidants
3. Absorption bases: has emulsifying agent, soaks up water
4. Emulsifying bases: water removable base, non ionic surfactant
5. Water soluble bases: Has polyethylene glycol PEGs = inc. water solubility, easy washable

Question 6

Selection of an appropriate base? Consider:

Answer 6

Desired release, topical vs transdermal, stability in base and occlusive/washable nature.

Question 7

Two methods of preparing ointment?

Answer 7

Fusion and incorporation

Question 8

Fusion method?

Answer 8

Ingredients combined and melted, heat labile substances added last when temp is low.

Question 9

Fusion method challnges

Answer 9

Don’t overheat = discolor and degrade, phase separation

Question 10

Creams - viscous semisolid emulsions for external application

o/w aq = rubbed onto skin, evaporates = ______

w/o oily = preferred over greasy ointments, ease of _____ and _____, occlusive layer and ______ effect

Answer 10

o/w aq = rubbed onto skin, evaporates = cooling effect

w/o oily = preferred over greasy ointments, ease of spreading and removing, occlusive layer and emollient effect

Question 11

Gels are?

Answer 11

A solid or semisolid system with at least two constituents - a crosslinked polymeric structure interpenetrated by a liquid

Question 12

GELS:

Has low conc of gelator molecules <15%, when touch solvent = _______ via physical or chemical interactions into extensive ________
Gels liquify upon contact with the skin and then dry as a non occlusive film

Answer 12

self assemble

mesh structure

Question 13

Classification of gels:

Organogels ?
Hydrogels ?

Answer 13

Organogels: prepd using organic or water insoluble materials

Hydrogels: use water or water soluble materials

Question 14

Hydrogels - cross linked network of polymers - have the ability to ___

Answer 14

Absorb a large amount of water while maintaing 3d structure + self healing = stick together to form network

Question 15

Pastes - 50% powder dispersed in fatty base

Answer 15

1. Good absorbing properties
2. Absorption of noxious chemicals
3. lease greasy that ointment

Question 16

Dry vs weeping skin

Ointment vs cream?

Answer 16

Dry = ointment, promote healing

Weeping = cream , for hairy too

Question 17

Barrier cream

Answer 17

Glove against water soluble irritants

Silicone = water repellent properties

Question 18

Emollients?

Answer 18

1. Soften and smooth skin
2. occlusive properties: prevent moisture loss
3. Used to correct dryness and sacaling

Question 19

Keratolytics ?

Answer 19

Helps remove outer layer of skin e.g salicylic acid, benzoyl peroxide

Question 20

UVA

UVB

Answer 20

UVA = deep into skin

UVB = reaches skin surface

Question 21

Chemical sunscreen

Answer 21

organic parts absorb UV
susitipble to photodegredation
SPF flexible to formulate

Question 22

Physical sunscreen

Answer 22

Inorganic components reflect UV
Cover broader range of UV
Beneficial for those with skin sensitivity

Question 23

SPF define

Include MED

Answer 23

Measure of sunscreen effectiveness
Non linear scale..

SPF= MED (protected skin)/MED(unprotected skin)

MED: the minimum amount of UV that produces redness 24 hours after exposure

minimal erhtyrmal dose