Lecithin is primarily used in pharmaceutical compounding as an emulsifying agent, surfactant, or wetting agent. Its main function is to stabilize mixtures of oil and water (emulsions). While some components of lecithin may exhibit minor antioxidant properties, it is not classified or utilized as an antimicrobial preservative. The other options are all well-established preservatives used to prevent the growth of bacteria, yeast, and mold in pharmaceutical preparations, thereby ensuring their stability and safety.

A. Benzalkonium chloride is a quaternary ammonium compound widely used as an antimicrobial preservative, particularly in ophthalmic, otic, and nasal preparations.

C. Sodium benzoate is a common preservative used to inhibit the growth of mold and yeast in acidic oral liquid preparations, foods, and cosmetics.

D. Benzyl alcohol is an aromatic alcohol frequently used as a bacteriostatic preservative in multi-dose parenteral (injectable) formulations and topical products.

1. Rowe

R. C.

Sheskey

P. J.

& Quinn

M. E. (Eds.). (2012). Handbook of Pharmaceutical Excipients (7th ed.). Pharmaceutical Press.

Lecithin: "Functional category: Emulsifying agent; emollient; solubilizing agent." (p. 417).

Benzalkonium Chloride: "Functional category: Antimicrobial preservative; antiseptic; disinfectant; solubilizing agent; wetting agent." (p. 56).

Sodium Benzoate: "Functional category: Antimicrobial preservative." (p. 627).

Benzyl Alcohol: "Functional category: Antimicrobial preservative; disinfectant; solvent." (p. 64).

2. Allen

L. V. (2018). Ansel's Pharmaceutical Dosage Forms and Drug Delivery Systems (11th ed.). Wolters Kluwer.

Chapter 18: Pharmaceutical Excipients: This chapter lists benzalkonium chloride

benzyl alcohol

and benzoic acid/its salts (like sodium benzoate) in the table of "Antimicrobial Preservatives." Lecithin is discussed and categorized under "Emulsifying and Suspending Agents." (Section: "Excipients Used in Liquid Dosage Forms").

3. United States Pharmacopeia and National Formulary (USP-NF). USP Pharmaceutical Dosage Forms.

This general chapter describes the typical components of various dosage forms. Preservatives are defined as substances added to inhibit microbial growth. Emulsifying agents

like lecithin

are defined as substances that promote and maintain the dispersion of one immiscible phase in another.