The London market dipped just before midday, with shares in Convatec slumping after the medical technology company cut its revenue growth forecast.
Convatec shares dived more than 20% after it cut its target for full-year organic revenue growth to 1%-2% from its previous estimate of 4%.
The company said it had been "severely" affected by supply issues.
The benchmark FTSE 100 index was down 3.47 points at 7,531.97.
Shares in GKN slid a further 2.2% after Societe Generale cut its rating on the engineering company to "hold".
On Friday, GKN shares fell by nearly 10% after it issued a profit warning.
However, mining shares bolstered the FTSE 100 after data from China indicated an improvement in manufacturing profits in the country.
Among the UK-listed mining stocks, Rio Tinto, BHP Billiton and Glencore were all up by about 2%.
On the currency markets, the pound rose 0.1% against the dollar to $1.3302 and was 0.3% higher against the euro at €1.1271.