Creams and Lotions

Question 1

What are creams?

Answer 1

Creams are viscous semi-solid oil in water or water in oil emulsions consisting of waxes, emollients and lubricants dispersed in an oil phase or a water phase, usually containing an emulsifying agent, stabilising agents, preservatives and in some cases, colourants

Question 2

Classify creams based on emulsion type

Answer 2

1. Aqeuous creams: : Aqueous creams are oil in water emulsions which are more comfortable and acceptable because they are less greasy and easily washed off with water. They usually have emollient properties
2. Oily creams: Oily creams are water in oil emulsions which are more difficult to handle. They have a more moisturizing effect because they provide an oily barrier which reduces water loss from the outermost layer of the skin. They also provide better release of lipophilic active ingredients.

Question 3

Provide an example of a typical aqueous cream formulation.

Answer 3

White petrolatum 25%
Stearyl alcohol 25%
Propylene glycol 12%
Sodium laury sulphate 1%
Water 37%

Question 4

Provide an example of a typical oily cream formulation.

Answer 4

White wax 12%
Cetyl esters wax 12.5%
Mineral oil 56%
Sodium boroate 0.5%
Water 19%

Question 5

Classify creams based on function.

Answer 5

Pharmaceutical or Medicated creams: These creams have various functions depending on the pharmacological activity of the active pharmaceutical ingredients e.g hydrocortisone cream, antibiotic creams, antifungal creams.

Cosmetic creams: Cleansing and cold creams, foundation and vanishing creams, night and massage creams, hand and body creams, all-purpose creams/sports cream etc.

All-purpose creams: These creams are used by sport persons or bypeople who do outdoor activities. They are oily in nature; they provide protective film to the skin; they make the rough surfaces of the skin smooth.
When applied in more quantity, it act as Nourishing, protective cream in order to protect the skin from sunburn,Night cream, Cleansing cream. When it is applied in less quantity, it act as hand and foundation creams

Question 6

Provide an example of a typical all-purpose cream formulation.

Answer 6

Stearic acid 15%
Lanolin 2%
Beeswax 2%
Mineral oil 24%
PEG-40 stearate 5%
Sorbitol 10%
Water, perfume, preservative q.s

Question 7

What are lotions?

Answer 7

Lotions are low-viscosity topical preparations intended for application to unbroken skin.

The inclusion of alcohol in lotions hasten their drying and accentuates their cooling effect while the addition of glycerol would keep the skin moisturized for a considerable time.

Lotions are applied without friction to external skin.
Lotions are suitable for hairy areas, skin prone to folliculitis, acne and intertriginous areas (areas prone to chaffing or dermatitis e.g neck creases, elbow pit, armpit, back of knee etc).

Question 8

Highlight the typical manufacturing process of creams and lotions.

Answer 8

1. Preparation of oily phase: the flake or powder ingredients are dispersed into an oily diluent (may be waxes or fatty solids that need to be melted firts or mineral oil). The temperature required is 70 -75 degree-celsius. At this point the emulsifying agent if oil soluble may be incorporated
2. Hydration of aqueous phase ingredients: emulsifiers, thickeners and stabilizers (if water soluble or miscible) are dispersed into water in a separate vessel. Heating will also be required to accelerate hydration at the same temperature as above.
3. Forming the Emulsion: The two phases are blended under vigorous agitation to form the emulsion. This step of the operation is the critical point in the formulation as the two phases must be at similar or same temperature. Also, addition should be steady without splashing or vortexing in order to prevent the entrapment of air. Subsequent cooling should be slow with adequate stirring to ensure homogeneity yet minimizing aeration.

Sudden cooling or excessive aeration can lead to granular product. The dispersed phase is added to the continuous phase. Agitator mixers can be used. Any API that may be present may then be dispersed efficiently.

After cooling to 30 – 40 degree-celsius, the cream can then be homogenized.

Question 9

What are the expectations of a good cream or lotion?

Answer 9

A good skin cream or lotion should aid the skin in carrying out its normal functions

Question 10

Mention 10 ingredients used in the formulation of creams and lotions and their percentages

Answer 10

1. Preservative (essential)
2. Emusifier (essential) 25% creams, 15% lotions
3. Thickener/stabiliser (essential) e.g., cetyl alcohol (1-4%), Xanthan gum (0.2-0.3%)
4. Oils e.g.,
   oily skin: jojoba, squalene
   normal skin: fractionated coconut oil, rice bran, apricot kernel
   dry skin: rice bran, apricot kernel, olive oil
5. Humectants e.g glycerin (1-7%), sodium lactate (1-2%)
6. Butters (optional) e.g., shea, cocoa
7. Water
8. Vitamin E: up to 0.1%
9. Fragrance: up to 1%
10. Silicones: 1-4% e.g., dimethicone, cyclomethicone

Question 11

Mention 3 examples of permeation enhnacers.

Answer 11

i. Ethanol
ii. Oleic acid
iii. Polyethylene glycol

Question 12

Mention 5 quality requirements of a good cream/lotion.

Answer 12

• It should liquefy at body temperature.
• The viscosity should be appropriately low enough to permit easy spreading.
• It should spread well enough.
• It should penetrate the epidermis via natural openings and contain enough light oils to permit penetration through the pores.
• It should be acidic as the pH of the skin is acidic, around 4.7 -5.8.