摘要:

SynopsisLimits imposed on the usage of thioglycolic acid, its salts and esters in cosmetic formulations require selective and sensitive analytical methods for their determination. In this study a convenient and reliable method based on high‐performance liquid chromatography (HPLC) has been developed. The method involves a precolumn reaction of the thiol compounds with ethacrynic acid to give thiol adducts which can be separated by reversed‐phase liquid chromatography and detected at λ= 273 nm.The derivatization reaction proved to be quantitative under mild conditions (20 min at pH 7.4 and room temperature) and the chromatographic conditions allowed thioglycolic acid, glyceryl monothioglycolate, thiolactic acid, and thioglycolic acid ethyl ester to be discriminated.The proposed method was successfully applied to the analysis of commercial cosmetic formulations containing thioglycolic acid and glyceryl monothioglycolate, fulfilling the requirements of a general and selective method for the analysis of aliphatic thiols in cosme

ISSN:0142-5463    

DOI:10.1111/j.1467-2494.1990.tb00530.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

SummaryQuantitative assessment of skin ageing is necessary for the evaluation of age modifying treatments. The particular method used must depend on the target of the intended treatment. It should also clearly distinguish between the degree of chronic environmentally‐induced trauma to the skin (predominantly photoageing) and the intrinsic ageing process. However, it is clear that no one measure will be adequate to define the extent of cutaneous ageing. Broadly speaking, the techniques available are either invasive or non‐invasive. Both have their uses. For example, topically applied retinoic acid 0.05% has been shown to increase epidermal thickness and decrease stratum corneum replacement time, using an invasive technique to determine the value for the first and a non‐invasive method to evaluate the second. Virtually all aspects of skin structure and function change with age. However, because of the importance with regard to appearance, some measure of solar elastotic degenerative change should be made. Profilometry techniques and ultrasound determination of skin thickness, as well as measurement of skin colour, may all have their use for this pu

ISSN:0142-5463    

DOI:10.1111/j.1467-2494.1990.tb00531.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

SynopsisWhat should one do, and why? Anyone asking such questions ‐ and everyone does so hundreds of times each day ‐ is concerned with ethics.Product development and testing raise many ethical questions. Particularly since the rise of ‘green consumerism’, these are of increasing concern to people outside the cosmetics industry, and so should be of interest to those inside it.The major problem seems to be that of reaching agreement on moral and ethical issues. Overcoming this problem involves investigating what is meant by ‘ethics’, and how decisions depend not on facts but on ‘facts‐as‐perceived’. These in turn depend on many factors, with one's philosophy being the most fundamental. The range of philosophical options is reviewed and it is proposed that wider discussion is the only just way to achieve agreement. Yet some things are not negotiable. There are certain key moral concepts in terms of which discussion must take place for it to be relevant. In ethics of human testing, ‘respect for others’, that is, avoiding exploitation, is the principal one. Some synthesis of the key moral concepts like that of Immanuel Kant is therefore recommended as the soundest and most widely acceptable basis for the necessary discussion.Defining the responsible use of human subjects covers a range of issues, moral, historical, legal and professional. For example, there may be ethical difficulties in deliberate damage induction as in SPF and irritancy testing. But above all, to avoid exploitation, there is a moral and also a legal requirement that subjects are truly volunteers. This is the basis of the concept of ‘informed consent’, required but not generally explained in current professional codes of practice. It is unjustified to exploit those who may be under duress, such as ‘in‐house volunteers' and those with low incomes. Hence in conclusion, criteria for obtaining valid informed consent are briefly reviewed.By considering issues such as these, we can help ensure that cosmetic scientists are true professionals, that is, those who recognise and are concerned with

ISSN:0142-5463    

DOI:10.1111/j.1467-2494.1990.tb00532.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

SynopsisA method was developed for evaluating in‐product preservative efficacy of solid cosmetics. Microbes (105–106colony‐forming units) resting on membrane filters were placed in direct contact with the surface of pressed eye shadows at room temperature in a moist chamber. At daily intervals, or as appropriate, the filters were removed and viable counts were determined by pour plates of modified letheen agar. Linear regression analysis was used to evaluate preservative efficacy. Decimal reduction times (D values) of 1.2–1.7 days were obtained forPseudomonas aeruginosaATCC 9027,Staphylococcus aureusATCC 6538 andEscherichia coliATCC 8739 on in‐house pressed eye shadows preserved with parabens and Germall 115. An average D value of 1.7 was also obtained forP. aeruginosaandS. aureuson a commercially pressed eye shadow containing the same preservatives as the in‐house formulation. However, this commercial product was either totally ineffective or about 3–6 times less effective againstE. coli. The predicted complete inactivation time corresponding to the above D value was about 9 days and was within the limits of current cosmetic guidelines for bacteria of ‘less than 0.1% survival b

ISSN:0142-5463    

DOI:10.1111/j.1467-2494.1990.tb00533.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY