Samples creams

System (6) was recommended for the analysis of hydrocortisone, cortisone, and their acetates in pharmaceutical preparations, as well as their separation from a number of impurities and decomposition products [154]. The sample (creams, ointments, lotions, or suppositories) was extracted with hot ethanol prior to introduction into the HPLC system. 

Considering CREAM, a sudden decrease in G modulus was observed 15 min and 32min after the gel point time, respectively. The rapid increase in the G modulus followed by a sudden decrease was always observed for this sample. This experiment has been carried out three times giving reproducible results. As this phenomenon could result from a sliding of the cone caused by syneresis, experiments were performed using a ridge cone and reduced stress conditions. The shape of the G curve obtained in these conditions was similar to the results reported in Fig. 10. It was concluded that this... 

Human skin is the largest organ in the human body. It is fundamentally important to health as the semi-permeable barrier - the first line of defence - between the body and the external world. However, it remains relatively inaccessible to conventional magnetic resonance imaging, firstly because it is thin and therefore requires high spatial resolution, and secondly because it is characterized by relatively short T2 relaxation times, particularly in the outermost stratum comeum. Conventional studies have not usually achieved a resolution better than 70-150 pm, with an echo time of the order of a millisecond or so. As a planar sample, skin has proved amenable to GARField study where it has been possible to use both a shorter echo time and achieve a better spatial resolution, albeit in one direction only. Such studies have attracted the interest of the pharmaceutical and cosmetic industries that are interested in skin hydration and the transport of creams and lotions across the skin. 

In early 2004, Hurlimann studied several cheese samples using D-T2 correlation experiments. The D-T2 spectrum shows predominantly two signals, one with a diffusion coefficient close to that of bulk water, and the other with a D about a factor of 100 lower. The fast diffusing component is identified as water and the other as fat globules. Two components of cheese in the D-T2 map has also been observed by Callaghan and Godefroy [65]. Recently, Hurlimann et al. have performed a systematic 2D NMR study of milk, cream, cheeses and yogurts [66], Some of the preliminary results are discussed here. 

The water Ti and T2 decrease from the regular milk, to cream and cheese, probably due to the higher casein (protein) concentration. However, the Ti/T2 ratio of the water component is found to be kept the same, 5, for all three samples. The reason for this unique value is not clear at present, possible due to the particular water-protein dynamics. 

The diffusion constant of water is consistent with the bulk water value for milk, however, it is slightly reduced in the cream sample and significantly reduced in the... 

Fig. 2.7.7 h —T2 and D-T2 spectra for milk, cream and cheese. Data for each sample are shown in one column and the various experimental results are in the different rows. First row T —T2 spectra. 7he two lines in each spectrum indicate the constant 7 -72 ratios of 1 and 2. 7he peak to the left of the lines correspond to the water signal with a h T2... 

The estimation of flow functions from an actual experiment is reported next. A multi-rate primary drainage experiment was conducted on a Texas Cream limestone sample. Hexadecane was used as the oleic phase and deuterium oxide (D20) was used as the aqueous phase. Protons are imaged, so only the oil phase is observed. The pressure drop data, production data and saturation data are shown in Figures 4.1.11-... 

Fig. 4.1.11 Calculated and measured pressure-drop data in a multi-rate primary drainage experiment on the Texas Cream limestone sample (Reprinted with permission for [34]).

The designation (aq) indicates a water solution. (Three other chemical states and their formula notations include liquid [1], solid [s], and gas [g].) The substance is in a solution, which is defined as a homogenous mixture of two or more substances. Homogenous means that the solution has a uniform chemical makeup. In other words, if you took samples of a solution from two different areas of its container, the two samples would look the same and have the same chemical composition, as would, say, two spoon-0 fills of vanilla ice cream scooped from different parts of the same... 

Massaccesi reported the development of a two-phase titration method for the analysis of miconazole and other imidazole derivatives in pure form and in pharmaceutical formulation [14], To the sample (10 mg) are added 10 mL of water, 10 mL of 1 M-sulfuric acid, 25 mL of dichloromethane and 1 mL of 0.05% indophenol blue (C.I. No. 49700) in dichloromethane solution and the solution is titrated with 10 mM sodium dodecyl sulfate until the color of the organic phase changes from blue to pale yellow. Results obtained for the drug in pure form, tablets, suppositories, cream and lotion agreed with the expected values and the coefficient of variation (n = 6) were 0.3-0.35%. Imidazole and the other constituents of the pharmaceutical preparations did not interfere. 

Some samples may change on standing. For example, the cream separates out from milk samples and the buttery lumps have to be broken up before the analysis. The composition of other samples may change due to, for example, fermentation. 

More elaborate sample preparation is often needed for complex sample matrices, e.g., lotions and creams. Many newer SP technologies such as solid-phase extraction (SPE), supercritical fluid extraction (SFE), pressurized fluid extraction, accelerated solvent extraction (ASE), and robotics are frequently utilized (see Ref. [2]). Dosage forms such as suppositories, lotions, or creams containing a preponderance of hydrophobic matrices might require more elaborate SP and sample cleanup, such as SPE or liquid-liquid extraction. 

Formulate hypothesis Due to the creamy nature of the sample contained in a tin container, you hypothesize that this is a container of a medicinal or cosmetic cream. 

Interpretation/results A GC-isotope ratio MS technique is used on known animal fats and the ancient samples. (In this technique, each peak eluting from the GC is combusted to C02 and its 12C-13C ratio is measured by a mass spectrometer [7].) The 13C ratio of the C-16 0 and C-18 0 fatty acids are plotted. The knowns are concentrated in specific areas on the plot, shown as ellipses in Fig. 21.16. The position of the cream sample points on this pattern recognition plot indicates that the fatty portion of the cream is from ruminant adipose tissue. 

Implementation The GC-MS of the sample headspace finds no perfume compounds. The cream is found to be greater than 80-wt% organic matter. Pyrolysis-GC-MS identified significant levels of glucose polymers, which were confirmed by FTIR to be either cellulose or starch. The iodine test revealed that the glucose polymer was starch. Further GC-MS analysis did not find cholesterol, but did find trace levels of a cholesterol degradation product. 

Formulate hypothesis The Roman cream sample is a cosmetic. 

Technique selection Recreation of the sample following the formula you uncovered can provide some insight and bolster the hypothesis that this was a beauty cream. 

Interpretation/results Your white cream had a texture similar to the Roman sample. The fat acts as an emollient and the starch reduces the greasiness of the cream. The Sn02 provides a white appearance when... 

Numerous CE separations have been published for synthetic colours, sweeteners and preservatives (Frazier et al., 2000a Sadecka and Polonsky, 2000 Frazier et al., 2000b). A rapid CZE separation with diode array detection for six common synthetic food dyes in beverages, jellies and symps was described by Perez-Urquiza and Beltran (2000). Kuo et al. (1998) separated eight colours within 10 minutes using a pH 9.5 borax-NaOH buffer containing 5 mM /3-cyclodextrin. This latter method was suitable for separation of synthetic food colours in ice-cream bars and fmit soda drinks with very limited sample preparation. However the procedure was not validated for quantitative analysis. A review of natural colours and pigments analysis was made by Watanabe and Terabe (2000). Da Costa et al. (2000) reviewed the analysis of anthocyanin colours by CE and HPLC but concluded that the latter technique is more robust and applicable to complex sample types. Caramel type IV in soft drinks was identified and quantified by CE (Royle et al., 1998). 

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