Browsing by Author "Ayalew, Tewodros"

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    The Effects of Government Transport Infrastructure Expenditure on Economic Growth in Ethiopia
    (Addis Ababa University, 2016-11) Ayalew, Tewodros
    The study investigates the effects of government transport infrastructure expenditure on economic growth in Ethiopia between 1975 and 2015 using annual time series data on Gross Domestic Product (GDP), transport infrastructure, human capital, defense, agriculture and culture and sport. The time series property of the data is checked for the presence of unit root using Augmented Dickey Fuller (ADF) unit root test technique .All variables are integrated, which implies that the variables has long run relationship .For the analysis co integration and Error Correction Model together with descriptive statistics (table, graph and chart) are used .The result reveals that government expenditure on transport infrastructure has positive and significant effects on economic growth .Additionally, from the expenditures incorporated for the analysis, expenditures on human capital, agriculture and defense have also positive and significant long run effect. However, expenditure on culture and sport has negative and significant impacts on the economic growth. On the other hand, results from the Vector Error Correction Model (VECM) shows that agriculture and transport infrastructure are significant in affecting economic growth in the short run but expenditure on human capital, defense and culture and sport are all insignificant. Based on the finding, the writer would like to recommend that government should allocate more budgets for the transport infrastructure investment together with agriculture, defense and human capital and reduce its expenditure on culture and sport.
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    Evaluation of the Fruit Mucilage of Cordia Africana as Table Binderin Paracetamol Table Formulation Optimization Using Response Surface Methodolgy
    (2022-06) Ayalew, Tewodros; Mary, Nisha
    Cordia africana Lam. (Amharic-wanza) (family: Boraginaceae) is a medium-sized evergreen tree that grows up to 4- 15 m with edible sticky fruits. It is native to Africa and is abundant in East Africa. The fruit mucilage of different species of cordia is found to be an excellent binder in tablet manufacturing. However, the binding ability of the cordiana african is not yet established. Therefore, this study aimed to evaluate the binding ability of Cordia africana fruit mucilage in tablet formulations using paracetamol as a model drug. The fruit mucilage of Cordia africana was extracted with maceration technique and characterized for different properties such as its compatibility with the model drug using the differential scanning calorimeter (DSC), the Fourier transform infrared spectroscopy (FTIR), surface morphology using scanning electron microscopy (SEM), and its crystallinity nature with X-ray Diffractometer (XRD). Furthermore, it was evaluated for loss on drying and moisture sorption studies. The mucilage was used to prepare granules using wet granulation method and finally compressed into tablet. The prepared tablets were evaluated for their hardness, disintegration time, friability, and drug release profile. Based on the preliminary study, concentration of disintegrant (starch -1500 (5-15%), mucilage concentration (3-10%), and compression force (50-100 N) were found to affect the response variables (Friability and Drug release) significantly (p value < 0.05). Therefore, the effect of these independent variables were further studied and optimized using the central composite design (CCD). The yield of extracted Cordia mucilage powder was found to be 29 %±0.9. The FTIR and DSC studies revealed that the mucilage is compatible with the model drug. The mucilage has shown no sharp peaks with noisy signal which was due to its amorphous nature. The loss on drying and moisture sorption studies were found to be 6%±0.02 and 1.3%-6.7%, respectively. The granules exhibited a good flowability and compressibility properties. All the prepared tablets have shown hardness value of less than 100 N and disintegration time in range from 0.55 to 10.27 minutes. The optimization study indicated that the quadratic model was the best fit model for both responses as per the model fitness summary. Furthermore, the ANOVA analysis for model adequacy testing confirmed the adequacy of the model for optimization.Accordingly, the model provided an optimum formulation at 5.32% of mucilage concentration, 5 % of disintegrant, and 76.71 N of compression force. Under this condition, the software predicted 83.3 % drug release at 30 minutes and 0.63% of friability. The validity of this optimum formulation was confirmed experimentally. The flowability of the granule of optimized tablet was found excellent as the angle of repose was found to be <30o while the Carr’s and Hausner ratios were determined as < 10 and < 1.11, respectively. Therefore, the results of this study suggest that the Cordia mucilage can be used as a tablet binder in tablet manufacturing.