Inclusion complex of colchicine in hydroxypropyl-β-cyclodextrin tenders better solubility and improved pharmacokinetics

Abstract

Context: Colchicine (CLC) causes cell death by destabilizing the tubulin unit. However, it ionizes at physiological pH resultant low bioavailability and therapeutic efficacy.

Objectives: We have attempted to augment the bioavailability of CLC by fabricating the inclusion complex with hydroxypropyl-β-cyclodextrin (HP-β-CD).

Materials and methods: CLC-HP-β-CD inclusion complex was prepared and evaluated with Fourier-transform infrared spectroscopy, differential scanning calorimetry, powder X-ray diffractometry, scanning electron microscopy, ¹H nuclear magnetic resonance (¹H NMR) spectroscopy and rotating frame overhauser enhancement spectroscopy (ROESY). Oral bioavailability of CLC-HP-β-CD inclusion complex was analyzed using high performance liquid chromatography method.

Results and discussion: Our phase-solubility data indicated the formation of a stable complex with K_c ~0.31 mM⁻¹ at pH 7.4. ¹H NMR ascertains that NHCOCH₃ moiety of CLC enters in the HP-β-CD cavity and deshielded the H-3 and H-5 protons. ROESY also correlates the H_f and H_g of CLC with H-3 and H-5 protons of HP-β-CD and indicates that H_f and H_g protons of CLC are present either as cis and/or trans form in CLC-HP-β-CD inclusion complex. Pharmacokinetic studies showed a 1.82-fold increase in absolute bioavailability of CLC upon complexation.

Conclusion: CLC-HP-β-CD inclusion complex may potentially be used as a viable formulation of CLC.

Keywords::

• Colchicine
• HP-β-CD
• inclusion complex
• pharmacokinetics
• bioavailability

Acknowledgements

We thank Gangwal Chemical Private Limited, Mumbai, India for the gift sample of HP-β-CD and Dr. Devender Kumar, Department of Chemistry, Guru Jambheshwar University of Science and Technology, Hisar, India for their kind help in analyzing the NMR spectra.

Declaration of interest

There are no conflicts of interest.