Evaluation of polybrominated diphenyl ethers in sediment of Lagos Lagoon, Nigeria

Certain pollutants, particularly synthetic organic compounds have given rise to important environmental concerns. New organic pollutants especially polybrominated diphenyl ether (PBDEs) employed in electronic equipment and in some household items as flame retardants are now finding their way into the aquatic environment as components of waste discharge into the water body. These highly hazardous organic pollutants of concern are persistent, can bioaccumulate and biomagnify in aquatic organism especially fish, and there appears to be no clear strategy for managing them. In this study, levels of polybrominated diphenyl ethers were determined in sediments collected from Lagos lagoon with the aim of generating a database which can be employed for management options. Sediment samples were collected using Van Veen grab for a period of one year from randomly selected sites in Lagos lagoon. The samples were soxhlet extracted with dichloromethane to obtain PBDEs extracts which were later cleaned up in a column of silica gel using hexane as eluant. The cleaned extracts were analyzed using gas chromatography coupled with electron capture detector. The total concentrations of PBDEs in sediments ranged from 0.11 to 23.33 mg/kg. In all the studied locations, BDE-28, BDE-153, BDE-154 and BDE 205 were detected in all sediment samples at concentration range of 0.22 to 23.33 mg/kg. Among the PBDEs congeners, sum of tri to hepta BDEs contributed 61.32%, while BDE-205 contributed 38.68% to the total PBDE in the sediment samples. Brominated congeners BDE-47, BDE-153 and BDE-154 (tetra and hepta BDEs) were abundant which contributed 18.31, 12.06 and 34.75%, respectively to the sum of tri to hepta BDE in the sediment. The composition patterns of PBDEs in Lagos Lagoon sediment samples revealed that technical deca-BDE mixture was the major pollutant sources with a minor contribution of penta-BDE mixture.Key words: Gas chromatograph, polybrominated diphenyl ether (PBDEs), sediment, Lagos Lagoon

Development and validation of a thin layer chromatographic method for the determination of artesunate and amodiaquine in tablet formulations

Artemisinin-based combination therapies (ACTs) are recommended for the treatment of uncomplicated falciparum malaria. Artemisinin derivatives are potent, rapidly acting antimalarias that reduce gametocyte carriage and patient infectivity; the sustained use of artesunate – amodiaquine reduced falciparum malaria transmission and progression of drug resistance. High efficacy of artemisinin-based combinations (artesunate plus amodiaquine) was observed in areas where malaria is endemic. This paper describes a routine, simple, precise, economical and reproducible thin layer chromatographic technique for the detection of artesunate and amodiaquine in tablet dosage form. Chromatographic separation was performed on glass silica gel plates (20 × 20 cm), paraffin – n-hexane (2:3 v/v) and ethylacetate – toluene (2.5:47.5 V/V) as mobile phases. Artesunate exhibited a detection limit of 0.001 mg/ml, while that of amodiaquine was 0.05 mg/ml. The two drugs were satisfactorily resolved with mean Rf values of 0.04 ± 0.03 and 0.06 ± 0.07 for artesunate and amodiaquine, respectively. The accuracy and reliability of the method was assessed by evaluation of linearity (0.001 – 6.0 and 0.05 – 6.0 mg/ml for artesunate and amodiaquine), precision (intraday RSD 10.68 – 25.78% and interday RSD 10.68 – 20.17 for artesunate, and intraday RSD 8.25 – 37.26% and inter day RSD 8.25 – 19.74% for amodiaquine) and specificity, in accordance with International Conference for Harmonization (ICH) guidelines. The method developed can be used for the analysis of ten or more formulation on a single plate and is a rapid and cost-effective quality-control tool for routine analysis of artesunate and amodiaquine as the parent drug and in tablet formulations.Key words: Artemisin based combination therapy (ACT), malaria, falciparum, artesunate, amodiaquine

High performance liquid chromatographic determination of proguanil after derivatisation with sodium benzoxazole-2-sulphonate

A simple, fast and reproducible method for the determination of proguanil using high performance liquid chromatographic with UV/Fluorescence detection is described. Proguanil was derivatised to its corresponding derivative [(N1-(4-chlorophenyl)-N5-(1 -methyl ethyl) imidocarbonimideamide-Nbenzoxazole]. The derivatisation reaction was conducted in methanol at 60°C using sodium benzoxazole-2-sulphonate under alkaline conditions. The resulting derivative was extracted with chloroform after which the extract was observed under UV lamp at 254 nm before TLC and HPLC analysis. Similarly, the derivatisation process was adapted for derivatisation of proguanil in urine sample. The reaction proceeded smoothly and rapidly. The extraction process was not cumbersome and eliminated the need for costly extraction and evaporation equipments. The resulting derivative fluorensced intensely under UV lamp. Direct HPLC analysis of the reaction mixture was found possible without interferences from excess reagent and endogeneous compounds like ammonium salts. The derivative eluted in less than seven minutes thus making the method suitable for routine use. The calibration plot was linear over the concentration range. A correlation regression of the order of 0.94 was obtained from the calibration curve which indicated a strong relationship between the instrument response and the concentration of proguanil. The discussion also summarizes the derivatisation chemistry that have not being fully explored to date but may find utility in future development of highly sensitive analytical methods for biquanide drugs

Using rating to evaluate quality of peanut products

Peanuts seeds roasted at 140°C for 40 min for either 25 or 35 min were rated to be of comparable quality with locally available commercial samples. Peanut butter prepared from seeds roasted at160°C for 30 min was also rated to be comparable with commercial samples, while Kwulinkwulis from seeds dryroasted at 150°C for 25 or 30 min prior to oil roasting of mashed seeds at 170°C for 2 min were accepted by the panel