Related Experiment Video
Updated: Aug 3, 2026

Preparation of Keratin Hydrolysate from Chicken Feathers and Its Application in Cosmetics
Published on: November 27, 2017
Do urea/ammonium lactate combinations achieve better skin protection and hydration than either component alone?
1Department of Dermatology, Klinikum der Stadt Karlsruhe, Germany. max@prof-gloor.de
Abstract:
Twenty subjects with healthy skin were treated with the following formulations for two weeks: drug-free W/O vehicle, 5% ammonium lactate (CAS 52003-58-4) in W/O vehicle, 5% urea (CAS 57-13-6) in W/O vehicle, 3% ammonium lactate + 3% urea in W/O vehicle, 5% ammonium lactate + 5% urea in W/O vehicle. These formulations were applied in randomized order to 6 test areas on the forearms; one area was left untreated. Repetitive washings were additionally performed in the second treatment week. TEWL, stratum corneum water content (corneometry-determined electrical capacitance), and cutaneous blood flow (laser Doppler) were measured at baseline, day 7, and day 14. 5% urea and both ammonium lactate/urea combinations produced significant stratum corneum hydration and improved stratum corneum barrier function; there were no significant differences between these three treatments.
More Related Videos
Related Concept Videos
Urea Cycle
Amides to Carboxylic Acids: Hydrolysis
Acid-catalyzed hydrolysis:
Hydrolysis of amides under acidic conditions yields carboxylic acids. Since the reaction occurs slowly, hydrolysis requires the conditions of heat.
The mechanism begins with the protonation of the carbonyl oxygen by the acid catalyst. The protonation makes the amide carbonyl carbon more...
Basicity of Aliphatic Amines
To measure the basicity of amines, two conventions are generally used. The first defines Kb as the basicity constant for the deprotonation reaction of water by the amine, as presented in Figure 1. Conventionally, lower Kb indicates higher...
Local Anesthetics: Common Agents and Their Applications
Cocaine is an ester of benzoic acid and methylecgogine. It is used to anesthetize and vasoconstrict locally. Currently, it is used primarily for topical applications. It is beneficial for surgeries on the upper respiratory tract, providing anesthesia and shrinking the mucosa. Cocaine in the form of cocaine hydrochloride is...
Titration of a Weak Base with a Strong Acid
Using the ICE table and substituting the Kb value, we calculate the initial pH of 50 mL of 0.1 M ammonia to be 11.11. Addition of 25 mL of 0.1 M hydrochloric acid to this solution of ammonia results in a buffer with an equal concentration of ammonia and ammonium ions. The pH of this buffer can be calculated by substituting these...
Surface Membrane Barriers
The outer layer of the skin, the epidermis, is a robust barrier comprising layers of closely packed keratinized cells. This dense arrangement prevents microbes from penetrating the body. The periodic shedding of epidermal cells...

