Accessing Document Properties needs long

Hello.

I wrote a Excel Macro which writes Names of Files from a SharePoint Library in an Excel Sheet.
Also some of the Document Properties are written in the sheet, but reading them needs quite a long time, so the macro is working for 15 minutes or so if the library consists of 200 files.
The code where i read the properties is as follows:

Dim filename, strFilename As String
Dim objFile As Object
Dim dp As Object


filename = Dir("\\server\*.doc*")

    Do While filename <> ""
        strFilename = "\\server\" & filename & ""      
        Set objFile = GetObject(strFilename)
        Set dp = objFile.ContentTypeProperties
        ThisWorkbook.Worksheets("Documentlibrary").Range("b" & lastrow_excel_DB + 1).Offset(i, 0) = dp("User / Support")
         i = i + 1
        filename =  Dir$()
   Loop

I figured out that the line "Set objFile = GetObject(strFilename)" is the one who needs this long time to execute.
Is there a possibility to get this running faster?
Thanks for any suggestions.