Shares in Aortech, the up-for-sale heart valve developer, bounced 31% yesterday as the formerly Scottish medical technology group reported strong interest in the sale process.

Aortech, where one-time chief executive Eddie McDaid returned last year as finance director and former Edinburgh-based F&C fund manager Bill Brown is chairman, said 11 parties were running the rule over the company and the board was encouraged by the number who were progressing to due diligence or management presentations.

The group's shares dropped 17% to 264p on July 3 when Aortech said it was running out of cash with barely £1 million left in the bank, and Mr Brown replaced Jon Pither as the company put itself up for sale.

But the shares, which by Friday had dipped further to 159p, jumped to 191p yesterday valuing Aortech at about £9m.

The potential buyers include "medical technology companies, biomaterials and coatings companies, contract manufacturing organisations and other strategic consolidators, as well as private equity investors," according to a statement issued by Mr Brown and Mr McDaid.

The aim was to recommend an offer by the end of October, but there was "no guarantee any such offer will be forthcoming or even proposed in the timeframe required, or as to the level of any proposal that may be made".

Aortech, which once employed 200 at Bellshill in Lanarkshire but closed the plant in 2004, admitted last month that "the business model of manufacturing polymers for other companies' products" was not sustainable, and it would have to find a buyer for its technologies or the entire business.

Mr McDaid stood down as chief executive in 2002, returned as a non-executive in 2005, and was appointed finance director last December, when the company moved from Australia to the US to get closer to its most promising market.