Aspen Pharmacare Holdings shares plunged the most on record as an already protracted deal to sell its infant-formula business dragged out even further, choking off cash flows and weighing on financing costs.

Africa’s biggest drugmaker announced the €740-million deal with French cheese maker Lactalis International in September, but completion of the sale has become mired in regulatory scrutiny. The Durban, South Africa-based company now sees the deal closing by the end of May as it awaits approval from New Zealand’s Overseas Investment Office, it said in a statement late Thursday.

Meanwhile, net debt rose to R53.5-billion at the end of December. The immediate priority is to bring that down, CEO Stephen Saad said in an interview.

“We had massive payments around anesthetics and we’ve paid most of that off, so we will de-gear automatically, but if we can de-gear quicker, we would like to,” the CEO said by phone. The company would consider other sales to reduce debt at a faster rate, he added.

Investors had already been disappointed with the price agreed for the infant-formula business, known as nutritionals, and Aspen shares have plunged more than 70% since the sale was disclosed. They traded 49% down at 71.44 rand as of 11:23 a.m. in Johannesburg, the lowest since December 2011.

The disposal will enable Aspen to focus on its main pharmaceutical operations. The company sells products such as hormones, anesthetics and antiretroviral medicines in more than 150 countries. The deal also reduces the drugmaker’s exposure to China, which has long been a target market.

Aspen said Thursday its “most promising pipeline opportunities” in the next couple of years lie in selling women’s health products in the US. The company has reached a memorandum of understanding with a partner it didn’t name that will distribute Aspen products in that country, the firm said.

Earnings before interest, taxes, depreciation and amortization fell 3% to R5.5-billion in the six months through December, the Durban, South Africa-based company said in the statement. Earnings per share, excluding some items, slumped 9%.

“Gearing is much higher than expected as the deal is not completed and there’s weak cash flow conversion,” said Andre Bekker, a Johannesburg-based analyst at Arqaam Capital, which has its price estimate and rating on Aspen under review following the earnings.