Dim oAccess As Microsoft.Office.Interop.Access.Application = New Microsoft.Office.Interop.Access.Application

                Dim sDBPath As String = ‘database path’

                oAccess.OpenCurrentDatabase(sDBPath, True, “password”)

                Dim accessDB As Database = oAccess.CurrentDb()

                accessDB.Close()

                accessDB = Nothing

                oAccess.CloseCurrentDatabase()

connection string 
 Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\mydatabase.mdb;Jet OLEDB:Database Password=MyDbPassword;