Stabilisation of hydrotropic temazepam parenteral formulations by lyophilisation

Abstract The solubilisation of temazepam by hydrotropic complexation has been investigated. Sodium salicyate and nicotinamide were used as hydrotropes. The former allowed appreciable solubilisation of temazepam but the effect was less marked in the case of diazepam. Increased solubilisation with temazepam was attributed to an increase in hydrogen bonding between drug and hydrotrope. Solutions of temazepam solubilised with sodium salicylate developed an unacceptable yellow colour on storage. This problem was overcome by lyophilisation. Lyophilised injections were readily reconstituted and initial assessment in rabbits indicated a satisfactory pharmacological response. Lyophilisation resulted in a preparation with excellent storage characteristics.