Aim: To prepare, evaluate and submit lathering shaving cream.
Requirements: Beaker, Water bath mortar, Suitable container.
Chemicals: Stearic acid, Coconut oil, Palm oil, KOH, NaOH, Glycerin, Methylparaben, Propylparaben, and Water.
Formulation Consideration: Lathering shaving cream is an o/w type of emulsion that dissolves readily in a water-producing lather with the help of a shaving brush. Properties desired for a good lather shaving cream are:
- It should be easy to disperse and apply to the skin.
- It should be able to maintain the skin moist and should confer lubricity to the skin.
- It should have the right consistency so that it does not fall off the face during shaving.
- It should be easily rinsed off from the face while shaving and from the brush and washbasin after shaving.
- It should be non-irritant and should not corrode the razor.
- Ease of transfer from tube to brush, ease with which foam is produced, and ease of spreading the foam on the face are desired.
- A close shave should have good wetting properties and stability and texture or foam especially foam of very tiny bubbles which are also desirable.
- It should not require excessive face for extrusion nor should it flow from the container unless applied.
- It must have the right consistency to prevent loss of foam or extrusion or else it will not stay on bristles and will flow into them.
Formulation: Coconut oil and stearic acid are the only fatty materials required. Coconut oil soap produces quick and profuse lather with poor lasting properties and breaks off easily. Thus it is supported by stearic acid. The presence of olive or palm oil may give some special effects and make the soap milder. Palm oil and olive oil soap is a softener and hence several times these two oils are added to a small quantity of coconut oil. They also help to reduce the slight irritancy of coconut oil soap. Stearic acid soap is used to give a desired mass to the shaving cream. Lanolin and castor oil may be added to increase the softness of the cream. Coconut oil soap is primarily used to give lather or very fine bubbles to give a close shave. Triethanolamine cannot be used to neutralize coconut oil fatty acid as it contains a considerable amount of fixed fatty acids in the form of esters and these do not react on storage though it gives a soft soap.
Hence stronger alkali sodium hydroxide and potassium hydroxide are used in combination as only potassium soap is soft. The ratio of potassium hydroxide to sodium hydroxide ranges from 4: 1 to 8: 1. Alkaline pH also helps in causing maximum swelling of hair keratin. However, coconut oil fatty acid does not react completely with alkali. The cream consistency spoils, so only part of stearic acid is incorporated first. Other ingredients include humectants like glycerin, sorbitol, and propylene Glycol up to 10%. Boric acid up to 1% is added to a completed cream to neutralize excess alkali if any. It helps to maintain the consistency of cream at high temperatures. Cetyl/glyceryl Monostearate is added up to 1% to give smaller bubbles size of lather so that the cream can accommodate a high quantity of water during use.
Perfumes: Commonly preferred perfumes are spicy like cloves or cinnamon quantity of perfume is very low as the product is not used for intact skin and must be sufficient to mask the odor. The addition of cetyl alcohol increases the lubricity of cream or even dimethicone may be added. Lanolin is used to get a soft cream with a less alkaline pH. As lather shaving creams are commonly placed in metal tubes, sodium silicate is added to prevent corrosion.
|Quantity Given (% w/w)
|q.s. to 100 gm
- Melt stearic acid, coconut oil, and Propylparaben in a beaker in a water bath at 60°-70°C.
- Heat KOH, NaOH, Propylene glycol, and Methylparaben in another beaker at the same temperature. Mix both the phases in a warm mortar with continuous triturating. Add perfume while warm and pack in a tube or a container.
Label: For external use only.
Storage: Store in a cool dry place, replace cap tightly after use.
Packaging: Packed in a suitable container with a cap.
Use: The purpose of shaving cream is to soften the hair by providing lubrication.
Directions: Place a small amount of shaving cream on the tip or center of the brush. Rub on the beard then shave with the razor.
Lathering Capacity Test: Add 1 gm of the cream to 10 ml of water in a 50 ml graduated cylinder. Note the initial volume (V1). Shake 30 times in 15 seconds. Note the volume of foam water (V2). Allow it to stand for 1 hour. The volume of foam above the liquid must extend to the top of the cylinder and must not reduce more than 10% of its original volume in 1 hour.
|Type of emulsion
|Lathering power (V2 − V1 ml)
|Foam Stability (time)
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