The deal does not contravene local competition law, with the clearance preceding a required vote on the transaction by shareholders of both companies, the Financial Supervision Commission (FSC) said in a statement last week.
Sopharma applied for clearance of the merger in January.
Sliven-based Biopharm Engineering produces infusion and injection solutions, veterinary medicines and immunological preparations.
Shares in Sopharma closed flat at 5.34 levs ($2.97/2.73 euro) in the company's most recent trading session on Friday.
(1 euro = 1.95583 levs)