Circassia Pharmaceuticals has officially declared an unconditional offer for Aerocrine and extended its acceptance period until 26 June.During the acceptance period, roughly 6.5m shares have been tendered, representing 93% of shared and voting rights in Aerocrine.Circassia first made a public cash offer of 2.55 Swedish kroner per share for Aerocrine on 15 May, with the acceptance period ending 11 June.As of 16:00 BST, Circassia was trading 1.1% higher at 284p.