Titus A.M. Msagati

Critical parameters in a supported liquid membrane extraction technique for ionizable organic compounds with a stagnant acceptor phase

The reviews cover important critical parameters that are often optimized in a supported liquid membrane extraction technique in both flat sheet and hollow fibre designs for ionizable organic molecules. Understanding of these parameters can enable one to predict the behavior of the compound before hand and thus reduce the number of optimization experiments. Moreover, less number of experiments can be also generated using statistical techniques which are now becoming more commonly used. Supported liquid membrane extraction optimal parameters such as the conditions of the pH of the acceptor and donor phases should easily be fixed from the pKa values of the compounds. Other parameters, including the polarity of the compound can help to predict the partitioning into the membrane and the behavior of the compound. The influence of parameters such as temperature on the mass transfer in supported liquid membrane depends on the design of the module, experimental design and type of mass transfer controlling the extraction process.

Analysis and quantification of parabens in cosmetic products by utilizing hollow fibre-supported liquid membrane and high performance liquid chromatography with ultraviolet detection

A simple and direct method based on hollow fibre‐supported liquid membrane (HFSLM) extraction and liquid chromatography equipped with a UV detector was developed for analysis and quantification of parabens in cosmetic products. The parabens analysed included methyl, ethyl, propyl, isobutyl and butyl paraben. The HFSLM extraction was carried out by employing di‐n‐hexyl ether as organic liquid that was immobilized in the hollow fibre membrane. The HFSLM extraction is simple, cheap, minimizes the use of solvents and uses disposable material. In an investigation of 11 paraben‐containing cosmetic products, the levels of parabens (sum of all parabens in a product) ranged from 0.43% to 0.79% (w/w) for skin care products, 0.07–0.44% for hair fixing gels and 0.30–0.52% for soap solutions. The levels of individual parabens in individual cosmetic products ranged between 0.03% and 0.42% w/w for skin care products, 0.07% and 0.26% w/w for hair fixing gels and between 0.11% and 0.34% w/w for soap solutions. Parabens were found in the highest concentrations in skin care products followed by soap solutions and the least amounts were found in hair fixing gels. Of the paraben‐containing products tested, all of them contained methyl paraben and about 90% contained propyl paraben in addition to methyl paraben. One product contained all the parabens analysed.

Supported liquid membrane extraction of 17β- estradiol and its metabolites in a variety of biological matrices

A sample purification and enrichment technique involving the use of supported liquid membrane (SLM) has been developed for the selective extraction of 17β- estradiol and its metabolites, namely 17β-estriol and estrone in various biological matrices and water. The biological matrices in which extraction was done included bovine kidney and liver tissues, milk and urine. The liquid membrane used to trap these compounds was made of 5% tri-n-octylphosphine oxide (TOPO) dissolved in a mixture of di-nhexylether and n-undecane (1:1, v/v). Separation and detection of the analytes obtained after SLM enrichment was done by liquid chromatography-electrospray mass spectrometry (LC-ESI-MS). The extraction efficiencies (E) for 1 ng/L estradiols mixture spiked in various biological matrices were in the order of 61‐80%, 52‐74%, 67‐89% and 61‐82% for kidney tissue, milk, urine and liver tissue, respectively. For spiked water sample, the extraction efficiencies were of the order 82‐96% from a 1 ng/L sample mixtures. LC-ESI-MS gave the detection limits of 0.3 ng/L, 1.8 ng/L and 2.4 μ μ μ μg/L for 17β

Synthesis of liposomes using α-phosphotidycholine and metabolites obtained from Elephantorrhiza elephantina and Pentanisia prunelloides

Plant saponins exhibit numerous pharmacological characteristics desirable for long term hyperlipidemic therapy through their cholesterol binding capacity due to the formation of liposomes/phytosomes which ultimately decreases the gastrointestinal absorption of cholesterol. This may result in the reduction of the blood plasma cholesterol levels; hence, mitigating cardiovascular and atherosclerotic problems that are associated with elevated plasma cholesterol concentrations. In this study, we reported for the first time a potential method of synthesizing phytosomes/liposomes from two medicinal plants Pentanisia prunelloides (Rubiaceae) and Elephantorrhiza elephantina (Fabaceae) saponin extracts and fractions using α-phosphotidycholine and cholesterol. This was done to explore the possibility of cholesterol binding capacity of fractions and extracts of the two medicinal plants as a justification of their application by traditional healers in managing body weight as well as averting hyperlipidemia and atherosclerosis. Spherical nanoparticles/phytosomes/liposomes were clearly identified in the TEM images with particle sizes ranging between tens and hundreds of nanometers. The zeta potential of the nanoparticles fell between -5 and +5 mV indicating that they have a high potential for aggregation; hence, making it relatively very difficult for the complexed cholesterol molecules to permeate the microscopic pores in the alimentary tract. Keywords: Frontier transmission infra-red (FTIR), liposomes, adjuvants, zeta-potential, α-phosphotidycholine African Journal of Biotechnology , Vol 13(12), 1402-1412