Recent in In vitro (page 10 of 11)

Ceramides in Skin Stress: Ultraviolet, Tape Stripping, and Crowding

Stress induces changes in the ceramide content of the skin, and may lead to compromised barrier function or skin diseases. Skin has ways of responding to these stresses, as we review here in the case of skin stressed by tape stripping, organic solvents, overcrowding, and ultraviolet (UV) irradiation.

Torsional Behavior of Human Hair by Single Fiber Torsion Pendulum Method

Torsional properties are described by the author as a method to distinguish between the surface and the bulk effects of actives in hair formulations.

A Laboratory Method for Measuring the Water Resistance of Sunscreens

A new laboratory in vitro method for the measurement of sunscreen water resistance uses spectrophotometric analysis of a model skin substitute before and after 80-minute immersion. It gives good correlation with the FDA’s 80-minute immersion SPF results (very water resistant). The method is especially good for screening new formulations or water-resistant technologies.

Testing for Dioxin and Furan Contamination in Triclosan

Each batch of triclosan should be analyzed for trace amounts of 2 3 7 8-tetrachlorodibenzo-p-dioxin and 2 3 7 8-tetrachlorodibenzofuran, which can form as unwanted manufacturing by-products, as shown in triclosan from six commercial Asian sources.

Testing A New Platform for Skin Care Emulsions

The authors describe how to test an ingredient for its potential as a skin care emulsion platform using, as an example, a new starch-based ingredient called hydroxypropyl starch phosphate.

The Safety Factor in Preservative Efficacy Testing

The authors explain how preservative efficacy testing is done to determine whether a formula is adequately preserved. Product contamination problems are frequently caused by inadequate preservation.

CTFA Preservative Challenge and Stability Testing Survey

CTFA conducted a survey in 1999 to determine the consistency of the industry's procedures for preservative and stability testing used by the cosmetic industry.

ATP Bioluminescence: Detecting Microbial Contamination in Dentifrices

In tests on eight dentifrice formulations, a bioluminescence system based on adenosine triphosphate (ATP) detected tested microorganisms qualitatively within 24-27 hours, compared to 5-7 days required for quantitative detection by standard methods.


The advent of the complete transcribing of the human genome will forever alter our perceptions of skin care, medicine and nutrition. This column is edited by Lawrence A. Rheins, PhD.

Open Assay Models (Washing) for Evaluating Subclinical Irritant Dermatitis

To avoid the acute irritation and dryness that a sincle occlusive surfactant application (24-h) patch tes4t may cause, and to more realistically approximate actual consumer use, an open assay model was chosen.

Evaluating Shine on Hair

Marketing research studies have shown that shine is one of they key benefits that women expect from hair care products, particularly from shampoos and conditioners. This article defines shine in the context of hair care and discusses ways to measure it.

Flexabrasion: A Method for Evaluating Hair Strength

Both bending and abrasion should be tested—along with extension—when evaluating hair strength, as the authors show in tests of a new active for increasing the strength of bleached hair.

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