PubMed · 13378968
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P SORGDRAGER. 1956-11-03. [Physical methods for testing fatty substances].. https://pubmed.ncbi.nlm.nih.gov/13378968/
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Acylglycerides present in oil seeds and meat can be transformed into volatile fatty esters using chlorotrimethylsilane (CTMS) and 1-pentanol as reagents. The volatile esters can then be analysed by GC. The method is quantitative and involves only minor sample manipulation. It often permits major recoveries of the total saponifiable lipids present in solid samples. A 40 min reaction time is enough to ensure the total conversion of saponifiable lipids to the corresponding FAPEs.
Conventional Soxhlet extraction assisted in the cartridge by ultrasound has been developed and used to extract the total fat content from oleaginous seeds such as sunflower, rape and soybean seeds. The application of ultrasound to the sample cartridge enormously decreases the number of Soxhlet extraction cycles needed for quantitative extraction of the fat, thus reducing the extraction time at least to half the time needed by the conventional procedures. The results agree well with those obtained by conventional Soxhlet extraction and the ISO reference method, both in terms of efficiency and precision. The repeatability of the proposed approach, expressed as relative standard deviation, was 0.9%; the within-laboratory reproducibility was 1.3%. Qualitative analysis of the extracted fat showed that the application of ultrasound does not change the composition of the oil.
The effect of incorporating caffeine and paracetamol on the structure and behaviour of Gelucire 50/13 has been studied with a view to establishing whether the choice of drug influences the solid structure and release mechanism. Dispersions containing up to 30% w/w drug were prepared and studied using differential scanning calorimetry (DSC), hot stage differential interference contrast microscopy (HSM), dissolution studies and erosion, water uptake (WU) and diameter change measurements. Gelucire 50/13 alone showed a broad melting endotherm using DSC, with two dominant peaks at 36 and 44 degrees C. While incorporation of caffeine did not result in marked changes to the profile, the presence of paracetamol increased the proportion of material in the lower melting peak. HSM studies indicated that the Gelucire crystallised into two main spherulitic conformations; paracetamol appeared to act as a nucleation site for the lower melting fractions while caffeine particles changed into a needle-shaped morphology on cooling the system from the liquid state. Dissolution studies at 37 degrees C showed the caffeine to be released at a relatively faster rate than the paracetamol. Kinetic modeling and direct measurement of the erosion profile indicated that the caffeine systems showed a greater preponderance for erosion than did the corresponding paracetamol systems. It is suggested that the paracetamol promotes the generation of the lower melting form of Gelucire 50/13 which in turn influences the release rate and mechanism. The study therefore indicates that the influence of the drug should be carefully considered when studying Gelucire matrix systems.