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In a randomized cross-over trial in 82 outpatients aged 15-45 yr undergoing conservative dentistry, a solution of flunitrazepam 0.25 mg ml-1 i.v. (average dose 0.014 mg kg-1) was compared with a solution of diazepam 5 mg ml-1 i.v. (0.29 mg kg-1). Cardiovascular changes, operating conditions and side-effects were similar. Forty minutes after the start of injection, about 85% of all patients could not remember the local anaesthetic injection. Thirty minutes after the end of treatment, only 25% of all patients had recovered. One week later, most patients receiving each drug had only vague memories of their treatment; they had felt more relaxed immediately after the i.v. injection than before. Drowsiness was equally common after flunitrazepam and diazepam. Ataxia was more prolonged with flunitrazepam but arm pain and venous thrombophlebitis were less frequent.

Functional crosslinked hydrogels were prepared from 2-hydroxyethyl methacrylate (HEMA) and acrylic acid (AA). The acid monomer was incorporated both via copolymerization and chain extension of a branching, reversible addition–fragmentation chain-transfer agent incorporated into the crosslinked polymer gel. The hydrogels were intolerant to high levels of acidic copolymerization as the acrylic acid weakened the ethylene glycol dimethacrylate (EGDMA) crosslinked network. Hydrogels made from HEMA, EGDMA and a branching RAFT agent provide the network with loose-chain end functionality that can be retained for subsequent chain extension. Traditional methods of surface functionalization have the downside of potentially creating a high volume of homopolymerization in the solution. Branching RAFT comonomers act as versatile anchor sites by which additional polymerization chain extension reactions can be carried out. Acrylic acid grafted onto HEMA–EGDMA hydrogels showed higher mechanical strength than the equivalent statistical copolymer networks and was shown to have functionality as an electrostatic binder of cationic flocculants.

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