Influence of β-cyclodextrin on the Properties of Norfloxacin Form A

Abstract

Abstract. Cyclodextrins are able to form host-guest complexes with hydrophobic molecules to result in the formation of inclusion complexes. The complex formation between norfloxacin form A and β-cyclodextrin was studied by exploring its structure affinity relationship in an aqueous solution and in the solid state. Kneading, freeze-drying, and physical mixture methods were employed to prepare solid complexes of norfloxacin and β-cyclodextrin. The solubility of norfloxacin significantly increased upon complexation with β-cyclodextrin as demonstrated by a solubility isotherm of the A L type along with the results of an intrinsic dissolution study. The complexes were also characterized in the solid stated by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Fourier-transform infrared (FT-IR) spectroscopy, X-ray diffractometry, scanning electron microscopy (SEM), and solid-state nuclear magnetic resonance (ssNMR) spectrometry. The thermal analysis showed that the thermal stability of the drug is enhanced in the presence of β-cyclodextrin. Finally, the microbiological studies showed that the complexes have better potency when compared with pure drug.

Study of inclusion complex of β-cyclodextrin and levofloxacin and its effect on the solution equilibria between gadolinium(III) ion and levofloxacin

“…S1). Upon complexation, the quinolone carbonyl stretching at 1724 cm -1 disappeared suggesting a deep inclusion into the hydrophobic environment of the b-CD cavity in the solid state [20,21]. NMR spectroscopy is a useful tool to provide the evidence for the inclusion of levofloxacin into b-cyclodextrin cavity.…”

Cyclodextrin Inclusion Complexes with Antibiotics and Antibacterial Agents as Drug-Delivery Systems—A Pharmaceutical Perspective

“…Several articles describe the complexes of individual polymorphs of norfloxacin with β-CD, obtained by the kneading and freeze-drying methods [ 171 , 172 , 173 , 174 ]. Norfloxacin exists in several solid forms: three anhydrous polymorphs (Forms A, B, and C), an amorphous form, a methanol solvate, and several hydrate forms, as well as salts and co-crystals [ 171 ].…”

Solid-State NMR Spectroscopy: A Key Tool to Unravel the Supramolecular Structure of Drug Delivery Systems

“…13 C nucleus is the second most obvious nucleus to study by NMR, as most drugs but also numerous DDSs contain carbon atoms, either in the grafted molecules or in the host structure itself (e.g., organic DDSs, MOFs, or functionalized porous silica). Solid dispersions can be analyzed by 13 C ssNMR to probe the association between amorphous drug and polymers through differences in NMR spectra that are not visible in the PXRD pattern [ 22 , 23 ] or to provide a direct way to probe drug–carrier interactions [ 24 , 25 , 26 ] and analyze the polymorphic forms of drugs [ 27 ], or to distinguish between the free and bound steroid drug in a DDS [ 28 ]. For example, in solid dispersions formed by α-, β-, and γ-CD in polyethylene glycol (PEG) 6000 g/mol with or without the addition of 5% w / w indomethacin (IM), the 13 C cross-polarization under MAS (CPMAS) NMR spectra of the α- and β-CD solid dispersions gave spectra that were essentially superpositions of the spectra of the pure components of the system.…”