You can proceed like this
TimeSpan.FromSeconds(
(CInt("0"+System.Text.RegularExpressions.Regex.Match(inputTime, "\d{1,2}(?=h)").ToString)*60*60)+
(CInt("0"+System.Text.RegularExpressions.Regex.Match(inputTime, "\d{1,2}(?=m)").ToString)*60)+
CInt(System.Text.RegularExpressions.Regex.Match(inputTime, "\d{1,2}(?=s)").ToString)
)