Methylisothiazolinone in cosmetic products in Tunisia

Contact allergy in atopic dermatitis: A prospective study on prevalence, incriminated allergens and clinical insights

BACKGROUND

The relationship between atopic dermatitis (AD) and allergic contact dermatitis (ACD) is a matter of debate.

OBJECTIVES

The purpose of our study is to assess the frequency of ACD in patients with AD, the incriminated allergens and the potential risk factors.

METHODS

This is a prospective study, including cases of AD diagnosed based on Hanifin and Rajka's criteria. All patients were patch tested to the European baseline series and corticosteroid series.

RESULTS

Ninety-three patients were included. Fifty-six patients (60.2%) had positive patch test results of which 71.4% were relevant. The most frequent allergens were: textile dye mix (24.7%), nickel (20.4%), cobalt (12.9%), isothiazolinone (8.6%), quanterium 15 (4.3%) and balsam of Peru (4.3%). Chromium, fragrance mix I, fragrance mix II and PTBP were positive in three cases (3.2%). Two cases of allergy to corticoids were identified. Facial involvement and duration of AD were significantly associated with contact sensitization (p = 0.04 and p = 0.005, respectively). Avoidance of relevant allergens resulted in a statistically significant decrease in SCORAD (p < 0.001).

CONCLUSIONS

ACD remains an important co-morbidity of AD. We observed a high frequency of ACD to textile dyes, isothiazolinones and fragrances. Avoidance of relevant allergens has resulted in an improvement of patients' skin symptoms.

Efficacy Comparison of an Automated Growth-Based System and Plate-Count Method on the Detection of Yeasts and Molds in Personal Care Products

OBJECTIVE

The present investigation studies the efficacy of an automated growth-based system for a quantitative determination of Candida albicans and Aspergillus brasiliensis in several personal care products. The main purpose of this validation study was to prove that the alternative method's entire performance is not inferior to the conventional pour-plate method for a quantitative determination of yeasts and molds. Thus, a performance equivalence was established in accordance with the United Stated Pharmacopeia (USP-NF) Validation of Alternative Microbiological Methods ˂1223˃.

METHODS

C. albicans and A. brasiliensis were pooled to use as inoculum (equivalent to 1.0 × 108 CFU/mL) in the suitability of the method test. PCP's preservatives were chemically neutralized leading to the yeast and mold recovery by means of the alternative microbiological method (AMM) and the pour-plate method. A correlation curve was generated for each PCP by plotting DTs relative to the corresponding log CFU values.

RESULTS

Thirty PCPs have been tested for quantification of yeasts and molds using an AMM. An equivalence of results was made through the construction of correlation curves that allowed the establishment of numerically equivalent results between the enumeration data from the reference method (CFU) and the alternative method (Detection times, DTs). Thus, following the guidelines of USP Ch.1223, essential validation parameters were tested, such as equivalence of results (Correlation coeficient, CC >0.95), linearity (R2 >0.9025), accuracy (% recovery >70%), operating range, precision (CV <35%), ruggedness (one-way ANOVA, P > 0.05), specificity, LOD, and LOQ.

CONCLUSION

It was shown that all the test results obtained from the alternative method were in statistical agreement with the standard plate-count method (PCM). Thus, this new technology was found to meet all the validation criteria needed to be considered for an alternative method for yeast and mold quantification in the PCPs tested.

HIGHLIGHTS

In accordance with the United Stated Pharmacopeia (USP-NF) Validation of Alternative Microbiological Methods ˂1223˃, the implementation of alternative methods can offer benefits in execution and automation while improving accuracy, sensitivity, and precision and reduce the microbiological process time compared to the traditional ones.