Insulin complexation with hydroxypropyl-beta-cyclodextrin: Spectroscopic evaluation of molecular inclusion and use of the complex in gel for healing of pressure ulcers

Abstract

The pressure ulcer healing is a complex process and difficult to be achieved. Insulin is known to promote wound healing, and when complexed with cyclodextrin presents improved solubility, stability and biological activity. Complexation of insulin with hydroxypropyl-beta-cyclodextrin (HPβCD) was performed in this work through the coprecipitation method, providing the inclusion complex (HPβCD-I). The spectroscopic techniques used to analyze the complex were H(1) NMR, FT-Raman and FT-IR/ATR. A gel containing the HPβCD-I complex was prepared and a clinical study was conducted in patients with pressure ulcers. The spectroscopic techniques allowed to confirm the complex formation through the inclusion of aromatic amino acids, such as phenylalanine present in the HPβCD cavity. Data obtained from the FT-Raman and FT-IR/ATR techniques, combined with the H(1) NMR results, showed the effectiveness of these techniques in evaluating the inclusion complex of HPβCD with insulin. Clinical studies demonstrated tissue revitalization and a trend (p=0.06) for a significant difference between the healing effect of the control gel and that with HPβCD-I complex. The creation of the gel prepared with insulin and HPβCD-I complex and its use in patients with pressure ulcers appears to be promising in wound healing and its possible use in hospital care.

Keywords: Carbopol 940(®) (PubChem CID: 6581); FT-IR/ATR; FT-Raman; Gel; Glycerin (PubChem CID: 753); Human insulin; Human insulin (PubChem CID: 16131429174); Hydroxypropyl-beta-cyclodextrin; Hydroxypropyl-beta-cyclodextrin (PubChem CID: 44134771); Methylparaben (PubChem CID: 7456); Propylparaben (PubChem CID: 7175); Triethanolamine (PubChem CID: 7618).