'This code demonstrates splitting a PDF into multiple PDFs 
On Error GoTo error
Dim pdfXpress1 As  New PdfXpress
pdfXpress1.Initialize
pdfxpress1.RaiseExceptions = True
Dim document As New PdfDocument
document. SetParentControl pdfXpress1   
document.OpenDocument "C:\multipage.pdf",""
Dim insertOpts As New InsertPagesOptions
insertOpts.SourceDocument = document
Dim docpageList As New PageList
Dim docpageRange As New PageRange
docpageList.Add docpageRange
insertOpts.PageList = docpageList
Dim so As New SaveOptions
Dim pageCount As Integer
pageCount = document.DocumentPageCount
Dim a As Integer
For a = 0 To pageCount - 1
          insertOpts.InsertAtPageNumber = 0
          docpageRange.StartPageNumber = a
          docpageRange.pageCount = 1
          Dim doc_new As New PdfDocument
          doc_new.SetParentControl pdfxpress1
          doc_new.NewDocument
          doc_new.InsertPages insertOpts
          so.FileName = "C:\split" + CStr(a) + ".pdf"
          doc_new.SaveDocument so
Next a
.
.
.
GoTo finish
error:
MsgBox Err.Description
finish:

Set document = Nothing
pdfxpress1.Terminate
Set pdfxpress1= Nothing