utl_compress.lz_compress removes file extension after compression
I am using database 19c (19.10.0.0.0) I have a requirement to compress file in a directory. File exists in directory with name ST300421.txt I want to compress it with name ST300421.zip
Compress is done successfully but file extension is removed for example inside ST300421.zip file ST300421 exists (without extension .txt) which use less for program to read and proceed further. Refer attached code which I am using.