Optimising poly(lactic-co-glycolic acid) microparticle fabrication using a Taguchi orthogonal array design-of-experiment approach

© 2019 Mensah et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.The objective of this study was to identify, understand and generate a Taguchi orthogonal array model for the formation of 10–50 μm microparticles with applications in topical/ocular controlled drug delivery. Poly(lactic-co-glycolic acid) (PLGA) microparticles were fabricated by the single emulsion oil-in-water method and the particle size was characterized using laser diffraction and scanning electronic microscopy (SEM). Sequential Taguchi L 12 and L 18 orthogonal array (OA) designs were employed to study the influence of ten and eight parameters, respectively, on microparticle size (response). The first optimization step using the L 12 design showed that all parameters significantly influenced the particle size of the prepared PLGA microparticles with exception of the concentration of poly(vinyl alcohol) (PVA) in the hardening bath. The smallest mean particle size obtained from the L 12 design was 54.39 μm. A subsequent L 18 design showed that the molecular weight of PLGA does not significantly affect the particle size. An experimental run comprising of defined parameters including molecular weight of PLGA (89 kDa), concentration of PLGA (20% w/v), concentration of PVA in the emulsion (0.8% w/v), solvent type (ethyl acetate), organic/aqeuous phase ratio (1:1 v/v), vortexing speed (9), vortexing duration (60 seconds), concentration of PVA in hardening bath (0.8% w/v), stirring speed of hardening bath (1200 rpm) and solvent evaporation duration (24 hours) resulted in the lowest mean particle size of 23.51 μm which was predicted and confirmed by the L 18 array. A comparable size was demonstrated during the fabrication of BSA-incorporated microparticles. Taguchi OA design proved to be a valuable tool in determining the combination of process parameters that can provide the optimal condition for microparticle formulation. Taguchi OA design can be used to correctly predict the size of microparticles fabricated by the single emulsion process and can therefore, ultimately, save time and costs during the manufacturing process of drug delivery formulations by minimising experimental runs.Peer reviewedFinal Published versio

Occupational and environmental health hazards associated with food processing and the use of personal protective equipment: A case study of Gari processing in southern Ghana

The processing of cassava into different staple foods, including gari, comes with occupational and environmental hazards. This research aimed at assessing the awareness of occupational health hazards associated with the processing of cassava (Manihot esculenta) into Gari, environmental impact and factors that influence the wearing of personal protective equipment. Ninety (90) Gari producers were randomly selected from Awutu Senya, Central Tongu and Ayensuano Districts of Ghana and interviewed using structured and semi-structured questionnaire. Results revealed that Gari producing industry was dominated by women (78.9%). The majority of cassava processors in the study area were aware of health hazards associated with the production of gari. However, most did not take measures to reduce or mitigate exposure to health risk. The Gari industry was less attractive to people above 60 years (8.9%). Training on occupational safety and health risk was low among processors. The usage of personal protective equipment (PPE) by processors was low. Only 3.3%, 16 and 17.8% used footwear, working gear and coat, respectively, during processing. Factors that influenced processors' decision to use PPE included years of experience in processing, knowledge of health risk associated with the processing of cassava into Gari, awareness of protective equipment and a visit to health facility relating to condition sustained at work. Producers were aware of the environmental effects of Cassava-mill effluent but did not treat effluents before discharge into the environment. Some environmental effects of mill cassava effluent identified by the gari producers were; reduction in soil productivity, destruction of vegetation cover, the killing of trees and bad odour. The low level of education and training accounted for the low usage of PPEs

Biosand Filtration as a Green Approach to Septic Tank Effluent Management in a Tertiary Institution in Ghana

Sewage and household effluents at some institutions in Ghana have been discharged into the ocean for years. Thisdegrades environmental media and is detrimental to ecological systems. The Three Local Plastic Barrel-Biosand Filter (TLPB-BSF) is an innovation on the slow sand filter that has been used to prevent discharge of raw sewage into the environment. The study aimed to test the performance of a modified BSF on sewage tank effluent and assess suitability of the filtrate for non-drinking purposes at a tertiary institution renamed KOTU to maintain confidentiality. Method: A filtration system made of three modified interconnected BSF was constructed on-site, with last filter connected to a storage tank. The modification was the provision of an additional media (charcoal) in the second barrel. Two sample collections were made from the system one week apart. The pre-filtrate samples were raw septic tank effluent (STE) and the samples obtained after running system was Biosand filter effluent (BSFE). Samples were analysed for physical and microbiological parameters at designated laboratories. Measured values of the parameters in pre-filtrate and filtrate samples were compared with EPA (Ghana) reference values. The removal efficiency of a parameter was computed as the difference between pre-filtrate and filtrate values expressed as a percentage of the pre-filtrate value. Results: Most of the effluent parameters from the BSF were within the EPA standards, while others were unacceptable. Removal efficiencies obtained for the parameters were: Ni trogen (83.3%), Phosphorus (89.5%), Total Suspended Solids (71.3%), Total Dissolved Solids (66.2%), Total coliform (99.9%), Faecal coliform (99.7%) and E. coli (97.6%). Conclusion: BSF is effective for upgrading physical and microbial quality of sewage at household and institutional level, prior to discharge in the environment. It produced a filtrate that met most of EPA standards for irrigation of non-edible crops

Dynamics of Maize Price in Ghana: Linear versus Nonlinear Cobweb Models

This paper intends to study the price dynamics of maize in Ghana using cobweb models derived from linear demand and nonlinear supply function and then compare with that from linear demand and supply functions which are constructed from real economic price and production data of maize. Comparative analysis of stability conditions of the equilibrium was discussed

Comparative study of proximate, minerals and fatty acid (as oleic) content of cooked and uncooked cow tripe consumed in Ghana.

Background: Meat and meat products such as the cow tripe are commonly eaten in Ghana, but their nutrient composition is not known and this affects evidenced based nutrition counseling and interventions. Objectives:The study was to compared the minerals, proximate and free fatty acid (FFA) (as oleic) composition of uncooked and cooked samples of cow tripe. Methods: Samples of cow tripewere obtained from the markets by purposive sampling which was later processed and analysed. The samples were chemically analysed to determine the nutrient content by using standard methods. Results were presented as means and standard deviations. The data from the uncooked and cooked tripe were compared using the Independent sample t-test. Results: The moisture content was significantly higher (p < 0.05) in the raw cow tripe than the cooked cow tripe. Energy, ash, fat and protein content were all significantly higher (p < 0.05) in cooked cow tripe than raw cow tripe. The carbohydrate content of raw cow tripe is not significantly higher (p > 0.05) than cooked cow tripe with a 100% change after cooking. No significant difference (p > 0.05) was found in the FFA (as oleic) content of the raw and cooked sample. Zinc content of cow tripe reduced after cooking by 99%. Phosphorus content was significantly higher when cooked(p < 0.05). After cooking also, there was a significant increase of copper in tripe (p < 0.05). Raw tripe recorded a very high iron content (app. 13.0 mg/100g), and did not decrease significantly after cooking. Conclusion: The study gave ample information on the proximate, oleic and mineralscomposition of raw and cooked cow tripe consumed in Ghana.The findings revealed that, cow tripe have considerable nutritional value,which can make significant impact in the nutrients intakes of individuals

Does automation improve stock market efficiency in Ghana?

The automation of the Ghana Stock Exchange (GSE) in 2008, among other reforms, was expected to improve the efficiency of the market. The extent of this truism has, however, not been empirically established for the GSE. In this study, we attempt to assess the impact of the automation on the efficiency of the GSE within the framework of the weak-form Efficient Market Hypothesis (EMH) based on the before and after approach. The study was done both at the aggregate and micro-level. The aggregate result showed that automation of the exchange did not improve the overall efficiency of the exchange. However, there is evidence that the number of market participants involved in the exchange has increased in the post-automation era. The results of the impact of the automation on the effi ciency of the microstructure are, however, mixed. Generally, the rejection of the null hypothesis under homoscedasticity was found to be robust to heteroscedasticity for some firms, but the reverse was the case for other fi rms. This implies that the rejection of the null hypothesis under homoscedasticity is due to both heteroscedasticity and serial correlation. Based on the findings, a mix of strategies aimed at improving the efficiency of the exchange are recommended.Keywords: automation; stock market efficiency; Ghana Stock Exchang

SOLAR DRYER WITH BIOMASS BACKUP HEATER FOR DRYING FRUITS: DEVELOPMENT AND PERFORMANCE ANALYSIS

Most solar dryers rely on only solar energy as the heat source. This condition limits its use in off -sunny periods such as cloudy, rainy seasons and after sunset. The objectives of this study were to: develop a solar dryer with biomass backup heater for drying fruits; analyze its performance; and carry out comparative analysis of the dryer with and without biomass backup heater. An indirect solar dryer was designed, constructed and analysed using 4mm slices of pineapples and mangoes. Temperature, humidity and ambient air temperature were measured using Tinytag data loggers, EasyLog – USB 2 and HI 91610C Thermo-hygrometer. A 300g weight of charcoal, costing GHC 0.5 (US$0.16)was fed into the backup heater every 1-2 hours with a running cost of US$ 1-2.88/day. The results showed that the moisture content (MC) of the pineapples reduced from 87% to 16%(wb) and that of mangoes reduced from 85% to 15.5% (wb). On average, solardrying with backup took 14-18 sunshine hours to attain the desired MC, while that without backup took 20-27 sunshine hours. With biomass backup heater the drying rates were: pineapples (32.5g/h) and mangoes (19.3g/h), while without backup the drying rates were: pineapples (23.7g/h) and mangoes (15.5g/h). Better performance was obtained when the dryer was with a biomass backup heater.Keywords: Moisture; dryer; temperature; solar; biomas

Covert contraceptive use among women attending a reproductive health clinic in a municipality in Ghana.

BACKGROUND: Covert contraceptive use (CCU) in sub-Saharan Africa is an indication of women's inability to exercise autonomy in their reproductive choices. The aim of this study was to assess the prevalence and determinants of CCU among a sample of FP clients in a municipality of Ghana. METHODS: We conducted a mixed method study among women attending a public reproductive health clinic in Sunyani, a city of over 250,000 inhabitants in Ghana. An initial survey inquired into sociodemographic characteristics, use of family planning (FP) methods and partner awareness of contraceptive use. The predictors of CCU were explored using logistic regressions. We used the findings to develop a guide which we applied in-depth interviews and focus group discussions with attendants at the same facility. Qualitative data analysis was conducted using a framework approach. RESULTS: We interviewed 300 women, 48 % of whom were aged between 26-33 years. The injectable was the most widely used method (56 %). The prevalence of CCU was 34 %. In multivariate analysis, single women were more likely to practice CCU than married or co-habiting women (Adjusted OR = 12.12, 95 % C.I. 4.73-31.1). Muslim and traditionalist women were similarly more likely to practice CCU than non-Muslim, non-traditionalist (Adjusted OR = 4.56, 2.29-9.06). Women who preferred to have their first or next child in 4 or more years from the time of the interview were more likely to be in CCU than women who intended to have children within 4 years of the interview (2.57; 1.37-4.83). Single women saw in covert use a statement of their social autonomy. To succeed in CCU, women wished that clinic attendance cards would not be given to them to keep at home. Though many participants saw in CCU a source of anxiety, they expected health workers to consider it and uphold confidentiality in the provision of services. CONCLUSIONS: Covert contraceptive use was high in this municipality and being single was the strongest predictor of the practice. Providers of FP services should reflect on how to adequately address the challenges faced by women who practice CCU

Manure Management, Quality and Mineralization for Sustaining Smallholder Livelihoods in The Upper East Region of Ghana

A survey was conducted in the Upper East region of Ghana to seek information on the fertility status of the soils, manure production, its management options and nutrient concentration that could be associated with quality. Analysis of soils from farmers’ fields showed that the soils are coarse textured, with low exchange capacity and organic matter contents. Available P in particular was very low with most of the soils having values less than 6.00 ppm. Four main types of cattle rearing systems were encountered; the field, kraal, compound and intensive. Fresh manure samples from each of these systems were collected air dried and analysed in the laboratory using standard protocols. The N and P contents of the manure ranged from 0.52 % to 1.14 %, and 0.28 % to 0.76 % respectively, which were below the critical levels for net mineralization. Polyphenol contents on the other hand were lower than the critical value of 4 %. Decomposition and nutrient release of the manure showed immobilization of total N during the first four weeks, suggesting the need to improve the quality by composting or applying it in combination with mineral fertilizers.Keywords: Crop production, fertilizer value, nutrient release, soil fertility

Midgut malrotation with volvulus discovered at an emergency caesarean section for placental abruption

Adult midgut malrotation with volvulus (AMMV) is an uncommon presentation which may be found incidentally during abdominal radiologic investigations or at laparotomy. We report a case of AMMV and small bowel gangrene in a 35-year-old Gravida four, Para three at 39 weeks, 4 days gestation who presented with a short history of worsening abdominal pain, repeated vomiting and abdominal wall guarding. Emergency caesarean section performed on account of a suspected placental abruption incidentally revealed a long segment of non-viable small intestine. Subsequent midline laparotomy disclosed a midgut malrotation with volvulus and bowel gangrene. This resulted in a 4.6m resection of non-viable small bowel with Ladd’s procedure. The patient developed moderate symptoms of short bowel syndrome in the post-operative period which was successfully managed non-operatively. This case report represents a rare diagnosis, in the West-African sub-region, of an adult midgut malrotation with volvulus mimicking a third trimester obstetric emergency