Continuous-Flow Multistep Synthesis of Cinnarizine, Cyclizine, and a Buclizine Derivative from Bulk Alcohols.

Cinnarizine, cyclizine, buclizine, and meclizine belong to a family of antihistamines that resemble each other in terms of a 1-diphenylmethylpiperazine moiety. We present the development of a four-step continuous process to generate the final antihistamines from bulk alcohols as the starting compounds. HCl is used to synthesize the intermediate chlorides in a short reaction time and excellent yields. This methodology offers an excellent way to synthesize intermediates to be used in drug synthesis. Inline separation allows the collection of pure products and their immediate consumption in the following steps. Overall isolated yields for cinnarizine, cyclizine, and a buclizine derivative are 82, 94, and 87 %, respectively. The total residence time for the four steps is 90 min with a productivity of 2 mmol h(-1) .

Application of adsorptive voltammetry for the detection of sub-nano molar cyclizine in biological fluids and tablets using fast Fourier transform continuous cyclic voltammetry in a flowing system.

An easy and fast Fourier transform continuous cyclic voltammetric technique (FFTCV) for monitoring of ultra trace amounts of cyclizine in a flow-injection system has been introduced in this work. The potential waveform, which was applied continuously on an Au disk microelectrode (12.5 microm in radius) consisted of the potential steps for cleaning, accumulation and potential ramp. The proposed detection method has some advantages, the greatest of which are as follows: first, it is no longer necessary to remove oxygen from the analyte solution and second, this is a very fast and appropriate technique for determination of the drug compound in a wide variety of chromatographic analysis methods. The detection limit for cyclizine was 1.8 ng ml(-1). The relative standard deviation (RSD) of the proposed technique at 5.0 x 10(-7) was 2.0 for 10 runs. The influences of pH of eluent, accumulation potential, sweep rate, and accumulation time on the determination of the cyclizine were considered. The proposed method was applied to the determination of cyclizine in a pharmaceutical preparation.

A preliminary ecotoxicity study of pharmaceuticals in the marine environment.

Environmental fates and effects of pharmaceuticals in the aquatic environment have been the focus of recent research in environmental ecotoxicology. Worldwide studies of common over-the-counter pharmaceuticals have reported detectable levels in the aquatic environment, but there are few studies examining impacts on marine habitats. These drugs can affect the functions of various vertebrates and invertebrates. The stability of two pharmaceuticals, cyclizine (CYC) and prochlorperazine (PCZ), in seawater was examined under light and dark conditions, as well as the toxicity of these compounds to larvae of the barnacle Balanus amphitrite, which is a cosmopolitan marine organism found in most of the world's oceans. CYC was very stable under all the tested conditions. On the other hand, PCZ degraded in light but not in the dark, and was more stable in seawater than fresh water. For the barnacle larvae, the LC50 of prochlorperazine was 0.93 microg/ml and the LC50 for CYC was approximately 0.04 microg/ml.

Drug combinations in syringe drivers: the compatibility and stability of diamorphine with cyclizine and haloperidol.

The compatibility and stability of 2B combinations of diamorphine hydrochloride (5-100 mg/ml) with cyclizine lactate (5-50 mg/ml), eight combinations of diamorphine (10-100 mg/ml) with haloperidol (2-4 mg/ml) and eight combinations of all three drugs was assessed after storage in 1 ml polypropylene syringes. Samples were stored for periods up to seven days in the light and at room temperature (22 degrees C). Five combinations of diamorphine with cyclizine precipitated immediately upon preparation. After analysis and determination of t90% values (the time taken for 10% degradation). 16 of the remaining 23 combinations were judged to be compatible (no signs of crystallization or precipitation) and stable (less than 10% loss of potency of either drug) after storage for 24 h. After seven days storage only four remained compatible and stable. The results indicate that ratios of diamorphine to cyclizine of 1:1 are stable at concentrations up to 20 mg/ml. An increase in diamorphine concentration necessitates a reduction in cyclizine to 10 mg/ml, and an increase in cyclizine concentration necessitates a reduction in concentration of diamorphine to 15 mg/ml to maintain stability over 24 h. All the combinations of diamorphine with haloperidol remained compatible and stable for seven days. The addition of haloperidol (2 mg/ml) to the diamorphine and cyclizine combinations had no detrimental effect on their compatibility and stability. A stability curve is included as an easy way for palliative care personnel to avoid potential problems with incompatibilities and reduced stability when using these combinations. Furthermore, to reduce the possibility of precipitation with mixtures containing cyclizine, the use of 0.9% sodium chloride should be avoided.