Quantitative characterization of chitosan in the skin by Fourier‐transform infrared spectroscopic imaging and ninhydrin assay: application in transdermal sciences

Abstract

The chitosan has been used as the primary excipient in transdermal particulate dosage form design. Its distribution pattern across the epidermis and dermis is not easily accessible through chemical assay and limited to radiolabelled molecules via quantitative autoradiography. This study explored Fourier-transform infrared spectroscopy imaging technique with built-in microscope as the means to examine chitosan molecular distribution over epidermis and dermis with the aid of histology operation. Fourier-transform infrared spectroscopy skin imaging was conducted using chitosan of varying molecular weights, deacetylation degrees, particle sizes and zeta potentials, obtained via microwave ligation of polymer chains at solution state. Both skin permeation and retention characteristics of chitosan increased with the use of smaller chitosan molecules with reduced acetyl content and size, and increased positive charge density. The ratio of epidermal to dermal chitosan content decreased with the use of these chitosan molecules as their accumulation in dermis (3.90% to 18.22%) was raised to a greater extent than epidermis (0.62% to 1.92%). A larger dermal chitosan accumulation nonetheless did not promote the transdermal polymer passage more than the epidermal chitosan. A small increase in epidermal chitosan content apparently could fluidize the stratum corneum and was more essential to dictate molecular permeation into dermis and systemic circulation. The histology technique aided Fourier-transform infrared spectroscopy imaging approach introduces a new dimension to the mechanistic aspect of chitosan in transdermal delivery.

Formulation Development, Characterization and Antifungal Evaluation of Chitosan NPs for Topical Delivery of Voriconazole In Vitro and Ex Vivo

“…Then, 2 mL of the sample was taken from the receptor compartment and 2 mL of fresh phosphate buffer (USP) solution of pH 5.5 was added to the recipient compartment. Samples were taken at intervals of 0 min, 30 min, 1 h, 2 h, 4 h, 8 h, 12 h, 16 h, 20 h, 24 h, and 28 h, and were analyzed on UV visible spectrophotometer (Shimadzu 1800, Nakagyo-Ku, Kyoto 604-8511, Japan) at 256 nm [ 30 , 31 ]. The temperature of the Franz diffusion cell was kept at 32 ± 1 °C.…”

Chitosan-Carboxymethyl-5-Fluorouracil-Folate Conjugate Particles: Microwave Modulated Uptake by Skin and Melanoma Cells

“…Low molecular weight chitosan was prepared by subjecting 2% weight/weight solution of chitosan dissolved in 2% volume/volume acetic acid (Merck, Germany) solution to microwave irradiation at 800 W for 9 minutes in the presence of 0.04% weight/weight of sodium chloride and characterized as reported by Nawaz and Wong (2016) (see Supplementary Materials).…”

“…Skin C-5-FU-F-NP and 5-FU permeation and retention were examined in vitro using skin harvested from healthy male Sprague Dawley rats Nawaz & Wong, 2017). Skin C-5-FU-F-NP content and distribution were characterized with a PerkinElmer Spotlight 400 imaging system (Nawaz & Wong, 2016). At least three replicates were conducted for each sample, and the results were averaged (see Supplementary Materials).…”

Optimization of Chitosan-Decorated Solid Lipid Nanoparticles for Improved Flurbiprofen Transdermal Delivery

“…The peaks at wavenumbers 3363 and 2988 cm –1 were also observed in optimized formulations (Figure ). The additional peaks that appeared at the wavenumber 1635 cm –1 in optimized formulations were ascribed to the presence of chitosan . Incorporation of the drug into the SLNs had negated effects on their functional groups.…”

“…The additional peaks that appeared at the wavenumber 1635 cm –1 in optimized formulations were ascribed to the presence of chitosan. 53 Incorporation of the drug into the SLNs had negated effects on their functional groups. This indicates that there is no interaction between the drug and polymer (chitosan) used in the present study.…”