1. Structure solution and reﬁnement of tetracaine hydrochloride from X-ray powder diﬀraction data
Harriott Nowell, J. Paul Attﬁeld,* New J. Chem., 2002, 26, 469–472
The crystal structure of tetracaine hydrochloride has been solved directly frompowder diﬀraction data using a global optimisation approach. The relatively large number of variables that were optimised in order to solve the crystal structure made this a challenging problem. Nevertheless, the structure was solved to a high degree of accuracy, in spite of the presence of a signiﬁcant degree of preferred orientation in the sample, which introduces systematic errors into the solution process. The subsequent restrained Rietveld reﬁnement made only small changes to the initial solution.
2. Solid-state assembly of carboxylic acid substituted pillararene and its host–guest complex with tetracaine
Oksana Danylyuk* and Volodymyr Sashuk*. CrystEngComm,2015, 17,719–722
We have chosen tetracaine as a model drug to explore the ability of carboxylic PA5 to include large pharmaceutical molecules inside its macrocyclic cavity. Tetracaine is a potent anesthetic drug widely used in topical and spinal anesthesia, as well as in ophthalmology. However, as a local anesthetic, tetracaine shows a short duration of action and adverse side effects, such as cardiac and neurological toxicity, accompanied sometimes by skin or tissue irritation. In order to improve the applications of tetracaine, its inclusion into the macrocyclic cavities of cyclodextrins, p-sulfonatocalixarenes and cucurbiturils has been studied both in solution and in the solid state.
3. Solid-state interactions of calixarenes with biorelevant molecules
Oksana Danylyuk and Kinga Suwinska*. Chem. Commun., 2009, 5799–5813
In each case bilayer arrangements of host and guest molecules are observed. For tetracaine and tamoxifen all the guest molecules are located in the guest layer. However the interactions between the uncomplexed guest molecules and the host molecules are diﬀerent in both structures. For tetracaine N–H…O hydrogen bonds occur between ‘free’ drug molecules and SO3- anionic groups of the para-sulfonatocalixarene. Between guest molecules N–H…O hydrogen bonds as well as C–H…π and C–H…O interactions are present. In the crystal structure with tamoxifen no interactions between host and ‘free’ guest molecules exist; only C–H…π interactions occur between guest molecules.