UPDATE 1-Prospect Capital Q4 profit lower than expected

* Q4 net investment income $0.32/shr vs est $0.36/shr

* Sees Q1 net investment income between $0.25-$0.30/shr

* Says Patriot deal to add at least $0.09-$0.10/shr per qtr

Sept 14 (Reuters) - Prospect Capital Corp (PSEC.O), a closed-end investment company, reported a lower-than-expected net investment income for the fourth quarter, hit by a 27 percent drop in interest income.

Net investment income for the quarter ended June 30, was $12 million, or 32 cents a share, compared with $13.7 million, or 50 cents a share, last year.

Analysts were expecting earnings of 36 cents a share, according to Reuters Estimates.

Total interest income was $12.1 million during the quarter, down from $16.5 million a year ago.

Prospect Capital expects first-quarter net investment income between 25 cents and 30 cents a share.

The company, which said in August it would buy Patriot Capital Funding Inc (PCAP.O) for $197 million, expects the deal to add to quarterly net investment income by at least 9 to 10 cents per share.

Shares of the company were down 3 percent to $10.11 in pre-market trade Monday. (Reporting by Brenton Cordeiro in Bangalore; Editing by Ratul Ray Chaudhuri)