Preparation and characterization of cosmetic emulsion with addition of active compounds

V teoretické části se závěrečná práce zabývá přehledem základních charakteristik a vlastností emulze. Velká pozornost je věnována výběru typu emulgátoru a výpočtu hydrofilně-lipofilní rovnováhy. Dále jsou rozebrány mechanismy a příčiny vzniku nestabilit emulzí a jejich možné prevence a metody stabilizaci. Součásti teoretické části práce je také současný stav řešené problematiky zaměřený na analýzu existujících metod pro stanovení stability emulze a jejich použití v praxi. Experimentální část práci je především zaměřena na přípravu kosmetických emulzí typu O/V s příměsí aktivních látek jako jsou UV absorbéry. Pro charakterizaci připravených vzorků byly změřeny hodnoty pH a stanoveny viskozity. Stanovení stability emulze bylo prováděno s využitím analytické odstředivky, a tyto výsledky byly dále korelovány s klasickými gravitačními testy stability (změna teplot uchovávání přípravku) podle metodických pokynů SÚKL (REG-49, REG 51), které jsou českou verzí direktivy 75/318/EEC: Stability tests on active ingredients and finished products Jsou popsány metody přípravy a složení jednotlivých vzorků, což je dále korelováno s uvedenými charakteristikami připravených krémů.In the theoretical part, this bachelor’s thesis focuses on the overview of the basic characteristics and properties of the emulsion. Great attention is paid to choosing the type of emulsifier and the calculation hydrophilic-lipophilic balance. The mechanisms andcauses of instability of emulsions and their possible prevention and methods of stabilization are analyzed. The present state of the problem aimed to the analysis of existing methods for determination of emulsion stability and their use in practice is also part of this thesis. The experimental part of the work is primarily focused on the preparation of O/W cosmetic emulsions with additive of active substances such as UV absorbers. To characterize the prepared samples, pH values were measured and viscosities determined. The stability of the emulsion was carried out using an analytical centrifuge, and these results were further correlated with the standard gravitational stability tests (change of storage temperature of the formulation) according to the SÚKL methodical guidelines (REG-49, REG 51), which are the Czech version of the 75/318 /: Stability tests on active ingredients and finished products. Methods of preparation and composition of individual samples are described, which is further correlated with the stated characteristics of prepared creams.

Gradient hydrogels – overview of techniques demonstrating the existence of a gradient

Gradient hydrogels are promising future materials which could be usable in tissue engineering (scaffolds), pharmaceutical (drug delivery systems with controlled release) and many others re-lated disciplines. These hydrogels exhibit a more complex inner (gradient) structure (e.g. con-centration gradient) than simple isotropic hydrogel. Gradient structured hydrogels could be beneficial in, for example, understanding intercellular interactions. The fabrication of gradient hydrogels is relatively deeply explored, but a comprehensive description of the physi-co-chemical techniques demonstrating the existence of a gradient structure is still missing. Here, we summarize the state-of-the-art of available experimental techniques which could be applica-ble in proving and/or describing in physico-chemical terms the inner gradient structure of hy-drogels. The aim of this paper is to give the reader an overview of the existing database of suit-able techniques for characterizing gradient hydrogels

Gradient Hydrogels—Overview of Techniques Demonstrating the Existence of a Gradient

Gradient hydrogels are promising future materials which could be usable in tissue engineering (scaffolds), pharmaceutical (drug delivery systems with controlled release) and many others related disciplines. These hydrogels exhibit a more complex inner (gradient) structure (e.g., concentration gradient) than simple isotropic hydrogel. Gradient-structured hydrogels could be beneficial in, for example, understanding intercellular interactions. The fabrication of gradient hydrogels has been relatively deeply explored, but a comprehensive description of the physico-chemical techniques demonstrating the existence of a gradient structure is still missing. Here, we summarize the state-of-the-art available experimental techniques applicable in proving and/or describing in physico-chemical terms the inner gradient structure of hydrogels. The aim of this paper is to give the reader an overview of the existing database of suitable techniques for characterizing gradient hydrogels

Gradient Hydrogels—The State of the Art in Preparation Methods

Gradient hydrogels refer to hydrogel materials with a gradual or abrupt change in one or some of their properties. They represent examples of more sophisticated gel materials in comparison to simple, native gel networks. Here, we review techniques used to prepare gradient hydrogels which have been reported in literature over the last few years. A variety of simple preparation methods are available, most of which can be relatively easily utilized in standard laboratorie

Development of cosmetic cream fulfilling standards of CPK certification

The aim of this diploma thesis is to propose a recipe of natural BB-creams with the desired properties (different color shades, that will be suitable for Central European skin type; flow properties, texture, spreadability, stability). The experimental part of the thesis is mainly focused on the development of BB-cream formulas. Several different formulations with diverse dispersion medium (water and aloe vera/water in a suitable ratio) have been proposed, and three different shades of BB-cream have been developed. The flow properties (viscosity) of the samples were measured, accelerated stability tests were realized by using the dispersion analyzer LUMISizer, the obtained results were correlated with the results of stress temperature tests. The results of the rheological analysis showed that the flow properties of the creams are comparable with commercially available preparations. Stress temperature tests have shown that prepared samples remain stable over 4 cycles (12 weeks) of changing storage temperature, accelerated destabilization tests performed by LUMISizer confirmed their stability. The colour coordinates of the developed shades were measured using a spectrophotometer and compared with commercial analogues. Also the questionnaire for sensory evaluation of preparations for more comprehensive analysis of prepared BB-creams was developed. The 25 female respondents of different ages participated in servey. The results of sensory evaluation showed that textural properties of developed creams are satisfactory for potential consumers

Development of cosmetic cream fulfilling standards of CPK certification

Cílem diplomové práce je návrh receptury přípravy přírodních BB-krémů požadovaných vlastností (barevné odstíny, které budou vhodné pro středoevropský typ pleti; tokové vlastnosti, konzistence, roztíratelnost, stabilita). Experimentální část práce je především zaměřena na vývoj receptury BB-krémů. Bylo navrhnuto několik různých receptur lišících se disperzním prostředím (voda a aloe vera/voda ve vhodném poměru) a také byly vyvinuty tři různé barevné odstíny BB-krému. Připravené vzorky BB-krémů byly charakterizovány z hlediska tokových vlastností (viskozita), následně byly provedeny zrychlené testy stability pomocí analytické odstředivky LUMISizer, které byly korelovány se stresovými teplotními testy. Výsledky reologické analýzy ukázaly, že tokové vlastnosti krému jsou srovnatelné s běžně dostupnými komerčními přípravky. Stresové teplotní testy ukázaly, že připravené vzorky zůstávají stabilní během 4 cyklů změny teplot uchovávání (12 týdnů), zrychlené destabilizační testy provedené pomocí zařízení LUMISizer potvrdily jejich stabilitu. Barevné koordináty vyvinutých odstínů byly změřeny pomocí spektrofotometru a porovnány s komerčními analogy. Za účelem komplexní analýzy připravených BB-krémů byl vypracován dotazník pro senzorické ohodnocení přípravků. Průzkumu se zúčastnilo 25 respondentek různé věkové kategorie. Výsledky zhodnocení senzorických vlastností potvrdily, že krémy jsou vyhovující pro potenciální spotřebitele z hlediska jejich texturních vlastností.The aim of this diploma thesis is to propose a recipe of natural BB-creams with the desired properties (different color shades, that will be suitable for Central European skin type; flow properties, texture, spreadability, stability). The experimental part of the thesis is mainly focused on the development of BB-cream formulas. Several different formulations with diverse dispersion medium (water and aloe vera/water in a suitable ratio) have been proposed, and three different shades of BB-cream have been developed. The flow properties (viscosity) of the samples were measured, accelerated stability tests were realized by using the dispersion analyzer LUMISizer, the obtained results were correlated with the results of stress temperature tests. The results of the rheological analysis showed that the flow properties of the creams are comparable with commercially available preparations. Stress temperature tests have shown that prepared samples remain stable over 4 cycles (12 weeks) of changing storage temperature, accelerated destabilization tests performed by LUMISizer confirmed their stability. The colour coordinates of the developed shades were measured using a spectrophotometer and compared with commercial analogues. Also the questionnaire for sensory evaluation of preparations for more comprehensive analysis of prepared BB-creams was developed. The 25 female respondents of different ages participated in servey. The results of sensory evaluation showed that textural properties of developed creams are satisfactory for potential consumers.

Novel Hydrogel Material with Tailored Internal Architecture Modified by “Bio” Amphiphilic Components—Design and Analysis by a Physico-Chemical Approach

Nowadays, hydrogels are found in many applications ranging from the industrial to the biological (e.g., tissue engineering, drug delivery systems, cosmetics, water treatment, and many more). According to the specific needs of individual applications, it is necessary to be able to modify the properties of hydrogel materials, particularly the transport and mechanical properties related to their structure, which are crucial for the potential use of the hydrogels in modern material engineering. Therefore, the possibility of preparing hydrogel materials with tunable properties is a very real topic and is still being researched. A simple way to modify these properties is to alter the internal structure by adding another component. The addition of natural substances is convenient due to their biocompatibility and the possibility of biodegradation. Therefore, this work focused on hydrogels modified by a substance that is naturally found in the tissues of our body, namely lecithin. Hydrogels were prepared by different types of crosslinking (physical, ionic, and chemical). Their mechanical properties were monitored and these investigations were supplemented by drying and rehydration measurements, and supported by the morphological characterization of xerogels. With the addition of natural lecithin, it is possible to modify crucial properties of hydrogels such as porosity and mechanical properties, which will play a role in the final applications