Colorless Clear Liquid Phenoxyethanol/Caprylyl Glycol Blend

Product Overview

DropPrev® CP35 is a colorless clear liquid cosmetic ingredient based on Phenoxyethanol and Caprylyl Glycol. Phenoxyethanol is among the most widely used permitted preservatives in cosmetics, with activity against bacteria, yeast, and mould; Caprylyl Glycol functions as a humectant, emollient, and preservative booster, enhancing phenoxyethanol’s antimicrobial performance through co-solvent action and membrane perturbation. The blend provides a broad-spectrum, low-odor, formulation-friendly liquid preservation system suitable for both leave-on and rinse-off products, including lotions, creams, cleansers, wipes, and hair care preparations.

Phenoxyethanol exerts its antimicrobial effect primarily by acting on the microbial cell membrane: it increases potassium ion permeability and reduces key enzyme activity, thereby inhibiting microbial growth. Its spectrum covers Gram-positive bacteria, Gram-negative bacteria, yeast, and mould, and it remains effective across pH 3–10. Phenoxyethanol has limited water solubility (approximately 2.6%), a physical boundary that necessitates appropriate co-solvent or blending strategies in high-water-content systems.

The value of Caprylyl Glycol in this blend is not to "replace" phenoxyethanol, but to amplify its efficacy through two complementary routes. First, as a co-solvent and wetting agent, it improves the aqueous solubility and partitioning of phenoxyethanol, helping the preservative more effectively contact and penetrate microbial cell walls. Second, Caprylyl Glycol itself possesses bacterial membrane-disrupting activity and can weaken microbial viability by inhibiting respiratory and energy metabolism. Together, these mechanisms deliver more reliable broad-spectrum protection at equal or lower total use levels.

Q: What pH range is suitable for this blend? Can it be used in acidic anti-acne formulas or mildly alkaline cleansers?

The antimicrobial backbone of DropPrev® CP35 is phenoxyethanol, which has a broad effective pH window; literature and comparable blend data support activity across pH 3–10, with pH 4–8 being the more commonly validated working range in practice. Accordingly:

• Acidic formulas (pH 4–6) , including systems built around salicylic acid, AHAs, or acidic anti-acne actives, can use the blend normally without requiring a higher use level solely due to acidity;

• Mildly alkaline formulas (pH 7–8) are also suitable, though the final use level should be confirmed by the specific system and preservative challenge testing;

• Strongly alkaline systems above pH 9–10 should be validated by actual challenge test results rather than applying the recommended range directly.

Importantly, pH compatibility addresses antimicrobial efficacy and chemical stability; it does not alter the 1.0% regulatory ceiling for phenoxyethanol. Formulators should optimize use level under both pH compatibility and regulatory constraints.