google charts not displaying on updating in updatepanel c#

var Drugresult = objdb.FetchCommonDrugGraphOnSearch(fromdate, todate);
            if (Drugresult.Count > 0)
            {
                StrDrug.Append(@"<script type=text/javascript> google.load( *visualization*, *1*, {packages:[*corechart*]});
                          google.setOnLoadCallback(drawChart);
                          function drawChart() {
                          var data = new google.visualization.DataTable();
                          data.addColumn('string', 'DrugName');
                          data.addColumn('number', 'Drug');
                          data.addRows(" + Drugresult.Count + ");");
                Int32 i;
                for (i = 0; i <= Drugresult.Count - 1; i++)
                {
                    StrDrug.Append("data.setValue( " + i + "," + 0 + "," + "'" + Drugresult[i].DrugName + "');");
                    StrDrug.Append("data.setValue(" + i + "," + 1 + "," + Drugresult[i].TotalCount.ToString() + ") ;");
                }
                StrDrug.Append("var chart = new google.visualization.BarChart(document.getElementById('DivDrug'));");
                StrDrug.Append("chart.draw(data, {width: 400, height: 300, title: 'No of Drug',");
                StrDrug.Append("vAxis: {title: 'Drug', titleTextStyle: {color: 'green'}},");
                StrDrug.Append("hAxis: {title: 'Drug Name', titleTextStyle: {color: 'green'}}");
                StrDrug.Append("});");
                //StrDrug.Append(" google.visualization.events.addListener(chart, 'select', function() {var selection = chart.getSelection();var row = selection[0].row; var col = selection[0].column;var year = data.getValue(row, 0);location.href ='../Report.ascx?date=' + year +'&type=1';});");
                StrDrug.Append("}");
                StrDrug.Append("</script>");
                LiteralDrug.Text = StrDrug.ToString().TrimEnd(',').Replace('*', '"');
            }