1. Salicylic Acid Semisolid Preparations
Faith White
Advisors: Dr. Antoine Al-Achi
&
Mrs. Janice Jackson-Freeman

2. Objective
The purpose of this experiment was to determine the distribution of salicylic acid in creams, ointments, and pastes.

3. Key Terms
Salicylic Acid
Cream
Ointment
Paste

4. Salicylic Acid (C7H6O3) COOH OH
Salicylic acid is a fine, white powder. It is used externally on the skin. It helps in the treatment of athlete’s foot, ringworm of the scalp, and the removal of warts, corns, and calluses. Salicylic acid is also incorporated into preparations for the treatment of acne, dandruff, seborrhea, and insect bites.

5. Cream
Viscous liquid or semisolid emulsions of either the oil/water(o/w) or water/oil (w/o) type.
Examples:
O/W type:shaving, hand, and foundation creams
W/O type: cold and emollient creams

6. Methods 1. Preparation of Cream
Ingredient
Ingredient weight(g) or amount(mL) with Salicylic Acid
Ingredient weight (g) or amount (mL) without Salicylic Acid
Water*
19mL
White Wax (beeswax)+
12g
Spermaceti Wax+
12.5g
Mineral Oil+
54g
56g
Sodium Borate*
.5g
Salicylic Acid 2g 0g
*Dissolve together using a steam bath till at the temperature of 70oC remove from heat, then immediately add salicylic acid.
+Dissolve together using a steam bath till at the temperature of 70oC.
-After both mixtures are at appropriate temperatures add together stirring rapidly and continuously until it has congealed.

7. Ointment
Semisolid preparations intended for the external application to the skin or mucous membranes; usually contain medicinal substances; properties vary.

8. Methods 2.Preparation of Ointment
Ingredient
Ingredient weight (g) or amount (mL) with Salicylic Acid
Ingredient weight (g) or amount (mL) without Salicylic Acid
^Sodium Lauryl Sulfate 1g
^Propylene Glycol
12g
#Stearyl alcohol
25g
#White Petrolatum
^Methylparaben
0.025g
^Propylparaben
0.015g
^water
33mL
35mL
Salicylic Acid 2g 0g
^Dissolve together using a steam bath till at the temperature of 75oC remove from heat, then immediately add salicylic acid
#Dissolve together using a steam bath till at the temperature of 75oC.
-after both mixtures are at the appropriate temperatures add together stirring rapidly and continuously until it has congealed.

9. Paste
Concentrates of absorptive powders dispersed (usually) in petrolatum or hydrophilic petrolatum. Often used in the treatment of oozing lesions. Are also used to restrict the area of treatment by acting as an absorbent.

10. Methods 3.Preparation of Paste
Ingredient
Ingredient weight (g) with Salicylic acid
Ingredient weight (g) without salicylic acid
#Zinc Oxide
25g
#Starch
White Petrolatum
48g
50g
Salicylic Acid 2g 0g
#Mix the ingredients together in a mortar and pestle, then add salicylic acid to mixture and then mix in the white petrolatum.

11. Preparation of Paste

12. Preparation of Diluted Alcohol
515 mL of 95% ethyl alcohol USP was measured using volumetric flask and graduated cylinder.
500 mL of deionized water was measured using volumetric flask.
Ethyl alcohol and deionized water was combined for a 49% alcohol solution.

13. Preparation of 0.1 N Sodium Hydroxide
8 grams of sodium hydroxide pellets was weighed and dissolved in deionized water and filled to 2 L mark on volumetric flask.

14. Methods
a. To 25 mL of diluted alcohol (49%), one drop of phenolphthalein TS and sufficient 0.1 N sodium hydroxide from a buret was used to produce a faint pink color.

15. Methods
b. Five grams from one preparation was added and mixed for five minutes at 300 rpms on a stir plate.

16. Methods
c. After the five minutes was up, the liquid in the flask was clear or white.

17. Methods
d. Drops of 0.1 N sodium hydroxide from a buret was added to the flask slowly till a faint pink color developed.

18. Methods
e. The amount of 0.1 N sodium hydroxide used was recorded to determine the precision.

19. Amount of Salicylic Acid in Dosage Forms
Each mL of 0.1 N sodium hydroxide is equivalent to mg of salicylic acid.

20. Results 5. The precision of our preparations.
Cream
45.3%
Ointment
38.4%
Paste
32.6 %

21. Conclusion
Due to inconsistencies in the data it was concluded that maybe there was not sufficient mixing time for the release of salicylic acid from the base...

22. or maybe it was because I couldn’t stop eating the paste!!

23. Acknowledgements
I would like to thank Dr. Al-Achi for all of his help in completing this experiment and Mrs. Freeman for all of her guidance, time, and patience.