Topical cream-based dosage forms of the macrocyclic drug delivery vehicle cucurbit[6]uril

Co-grinding Effect on Crystalline Zaltoprofen with β-cyclodextrin/Cucurbit[7]uril in Tablet Formulation

This work aimed to investigate the co-grinding effects of β-cyclodextrin (β-CD) and cucurbit[7]uril (CB[7]) on crystalline zaltoprofen (ZPF) in tablet formulation. Crystalline ZPF was prepared through anti-solvent recrystallization and fully analyzed through single-crystal X-ray diffraction. Co-ground dispersions and mono-ground ZPF were prepared using a ball grinding process. Results revealed that mono-ground ZPF slightly affected the solid state, solubility, and dissolution of crystalline ZPF. Co-ground dispersions exhibited completely amorphous states and elicited a significant reinforcing effect on drug solubility. UV-vis spectroscopy, XRPD, FT-IR, DSC, ssNMR, and molecular docking demonstrated the interactions in the amorphous product. Hardness tests on blank tablets with different β-CD and CB[7] contents suggested the addition of β-CD or CB[7] could enhance the compressibility of the powder mixture. Disintegration tests showed that CB[7] could efficiently shorten the disintegrating time. Dissolution tests indicated that β-CD and CB[7] could accelerate the drug dissolution rate via different mechanisms. Specifically, CB[7] could accelerate the dissolution rate by improving disintegration and β-CD showed a distinct advantage in solubility enhancement. Based on the comparative study on β-CD and CB[7] for tablet formulation combined with co-grinding, we found that CB[7] could be considered a promising drug delivery, which acted as a disintegrant.

Synthesis of a Disulfonated Derivative of Cucurbit[7]uril and Investigations of its Ability to Solubilize Insoluble Drugs

Cucurbit[7]uril (CB[7]) is currently being investigated as a solubilizing agent for insoluble drugs. We recently found that acyclic CB[n]-type receptors that bear sulfonate solubilizing groups are well suited for this application. Herein, we report cucurbit[7]uril derivative (1) that bears two sulfonate groups on its convex face that we hypothesized would be a superior solubilizing excipient for insoluble drugs. Before using 1 for drug solubilization experiments we showed that 1 does not self-associate and that it retained its ability to bind to diammonium compounds as common guests for CB[7] sized cavities. X-ray crystallography shows that 1 maintains the key structural features of CB[7] with only minor ellipsoidal deformations at the equator and carbonyl portals of 1. Unfortunately, the aqueous solubility of 1 (20 mM) is slightly lower than CB[7] (20-30 mM) which limits its potential as a solubilizing excipient for insoluble drugs. We created phase solubility diagrams for the solubilization of three drugs (camptothecin, albendazole, cinnarizine) with two different containers (1 and CB[7]). CB[7] and 1 exhibit comparable solubilization abilities (e.g. K_a and maximum solubility) toward camptothecin and albendazole but 1 is an inferior solubilizing agent for cinnarizine because of the low solubility exhibited by the 1•cinnarizine complex.