| Simethicone is a mixture of polydimethylsiloxane (PDMS) and silicon dioxide, with lower surface tension, better biological and chemical stability. This product was developed in the 70s of the last century by the German Berlin-Chemie AG. It has been used for more than 30 years in Europe, the United States, and other regions. Simethicone emulsion has been used extensively in clinical at home since Chinese Ministry of Health allowed to import simethicone emulsion which is produced by German Berlin-Chemie AG. Simethicone is mainly used for treating gastrointestinal complaints caused by gas accumulation in the abdomen in clinical, such as belching, flatulence, and postoperative abdominal distention, etc. It also can be used for treating functional dyspepsia, irritable bowel syndrome, postoperative ileus, and adjuvant of abdominal imaging examinations. It is also reported that simethicone is used as an adjunct to contrast media suspensions.The USP-34 and BP 2011 edition both contained simethicone and its preparations. But the USP and BP just determined the total content of the volatile matter of simethicone, the structure and content of every component was not determined. And they only determined the defoaming properties of simethicone and its preparations qualitatively, did not have a quantitative method. The Ch.P has never contained simethicone, but dimethicone and its tablet and aerosol, it also did not contain structure analysis of volatile matter and the check item of defoaming properties. Consequently, it has very important theoretical and practical significance to study the structure and content of volatile matter, establish a quantitative method for checking defoaming properties, determine the content of simethicone in new preparations by IR, for the quality control of simethicone and its preparations, monitoring of drug side effects in clinical, rational drug selection of doctors and the patients.Components analysis of volatile matter in simethicone by Gas Chromatography- Mass Spectrometry. We established a method to analysis components of volatile matter in simethicone API qualitatively and quantitatively. The qualitative analysis of components of volatile matter in simethicone with the viscosity of 500cst was studied using GC-MS, through the interpretation of the mass spectrogram and investigation of the law of peaks; Area normalization method was used for preliminary quantitative analysis according to GC spectrogram. In conclusion,42 components were identified, which accounted for over 99.21%of the total volatile matter, included two sets of homologous compound:20 species of linear Methylpolysiloxane (MDmM, MM to MD21M) and 22 species of cyclic Methylpolysiloxane (Dn, D3to D24). The results are guiding significance on improving the product process of polydimethylsiloxane and investigating the quality control of simethicone theoretically.Comparative study on the defoaming properties of simethicone and dimeticone. The defoaming properties of simethicone and dimeticone was measured and compared, to provide a basis for rational drug selection in clinical. The defoaming properties of simethicone and dimeticone before and after adding the dispersant were measured by the self-builted cylinder method. The relevant different contents of silica were determined. The defoaming properties of simethicone and dimeticone were compared through the cylinder method, shake-flask method, bubbling method and roche bubble method. The defoaming properties of simethicone and dimeticone added the dispersant that was tertiary butyl alcohol or methyl ethyl ketone were better than the pure simethicone and dimeticone (P<0.05). The defoaming properties of dimeticone whose kinematic viscosity was 500mm2·s-1 were better than other dimeticone (P<0.05). Single silica had weak defoaming properties. The defoaming properties of simeticone with 5% silica were best (P<0.05). The defoaming activity and foaming suppression of simethicone were 9.2 times,1.6 times than that of dimeticone through the cylinder method. The defoaming activity and foaming suppression of simethicone were 12.2 times,1.3 times than that of dimeticone through the Shake-flask method. The defoaming properties of simethicone were better than that of dimeticone through bubbling method and roche bubble method. In conclusion, the defoaming properties of simethicone are better than that of dimeticone, the defoaming activity of simethicone is about 10 times than that of dimeticone.Determination of simethicone in Compound Alverine Citrate Soft Capsules by IR. An infrared spectroscopy method was establised to determine simethicone in Compound Alverine Citrate Soft Capsules. Simethicone in the drug was extracted by N-hexane to assay quantitatively, on the basis of the characteristic absorption peak of polydimethylsiloxane in 1260cm-1 wave number of Si-CH3 group’s symmetric deformation vibration. The determined IR wave number range was 1330cm-1 to 1180cm-1; The resolution was 2.0 cm-1; The choosed slit was wide, and the response speed was fast. The setting temperature was 25℃, RH was 50%. On the selective analytic condition, the linear range was 1.0 mg-mL-1-24.0 mg-mL-1 (r=0.9965) and the average recovery (n=9) was 100.79% with RSD 1.68%. The system suitability, precision and stability were fine. The content test results of three batchs sample products were 98.70%,97.93% and 98.58% of the labelled. The method is simple, tachy, accurate and specific. It can be used to assay simethicone in Compound Alverine Citrate Soft Capsules. |
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