arr(i, 1) = RGB(255, 200, 200)

Range(Cells(1, 1), Cells(10, 1)).Interior.Color = arr(i, 1)

Sub test()
    ActiveCell.Interior.Color = myRGB("RGB(255, 200, 200)")
End Sub

Function myRGB(RGBtext As String) As Long
    Dim arr As Variant
    arr = myRGBarray(RGBtext)
    If Not IsEmpty(arr) Then
        myRGB = RGB(arr(0), arr(1), arr(2))
    End If
End Function

Function myRGBarray(ByVal RGBtext As String) As Variant
    If RGBtext Like "RGB(*, *, *)" Then
        RGBtext = Mid(RGBtext, Len("RGB(1"))
        RGBtext = Left(RGBtext, Len(RGBtext) - 1)
        myRGBarray = Split(RGBtext, ", ")
    End If
End Function