[1] Department of Pharmacology and Clinical Pharmacy, School of Pharmacy, College of Health Sciences, Addis Ababa University, P. O. Box 1176, Addis Ababa
[2] Department of Surgery: Neurosurgery Unit, School of Medicine, College of Health Sciences, Addis Ababa University, P. O. Box 1176, Addis Ababa
[3] School of Pharmacy, College of Public Health and Medical Sciences, Jimma University, P. O. Box: 378, Jimma