Biomedical and Pharmacological Uses of Fluorescein Isothiocyanate Chitosan-Based Nanocarriers

Chitosan-based nanocarriers (ChNCs) are considered suitable drug carriers due to their ability to encapsulate a variety of drugs and cross biological barriers to deliver the cargo to their target site. Fluorescein isothiocyanate-labeled chitosan-based NCs (FITC@ChNCs) are used extensively in biomedical and pharmacological applications. The main advantage of using FITC@ChNCs consists of the ability to track their fate both intra and extracellularly. This journey is strictly dependent on the physico-chemical properties of the carrier and the cell types under investigation. Other applications make use of fluorescent ChNCs in cell labeling for the detection of disorders in vivo and controlling of living cells in situ. This review describes the use of FITC@ChNCs in the various applications with a focus on understanding their usefulness in labeled drug-delivery systems.

Preparation of Chondroitin Sulfate-Glycyl-Prednisolone Conjugate Nanogel and Its Efficacy in Rats with Ulcerative Colitis

A conjugate between chondroitin sulfate (CS) and glycyl-prednisolone (GP), named CS-GP, was produced by carbodiimide coupling at a high GP/CS ratio. CS-GP was not water-soluble and gave a nanogel (NG) in aqueous solution. Two types of nanogels, NG(I) and NG(II), with prednisolone (PD) contents of 5.5 and 21.1% (w/w), respectively, were obtained. They had particle sizes of approximately 280 and 570 nm, respectively, and showed negative ζ-potentials of approximately -40 mV. The PD release rate was slower in the nanogels than in a solution of CS-GP with a PD content of 1.4% (w/w). The PD release rate was slower in NG(II) than in NG(I), and was elevated at pH 7.4 than at pH 6.8. NG(II) was applied in vivo to rats with trinitrobenzene sulfonic acid (TNBS)-induced colitis, and its therapeutic efficacy and pharmacokinetic features were investigated. The therapeutic efficacy of NG(II) was slightly better than that of PD alone. Drug delivery to the lower intestines was enhanced with NG(II). The CS-GP nanogel has potential as a potent DDS for the treatment of ulcerative colitis.

Nanogels of Succinylated Glycol Chitosan-Succinyl Prednisolone Conjugate: Preparation, In Vitro Characteristics and Therapeutic Potential

A novel anionic nanogel system was prepared using succinylated glycol chitosan-succinyl prednisolone conjugate (S-GCh-SP). The nanogel, named NG(S), was evaluated in vitro and in vivo. S-GCh-SP formed a nanogel via the aggregation of hydrophobic prednisolone (PD) moieties and the introduced succinyl groups contributed to the negative surface charge of the nanogel. The resultant NG(S) had a PD content of 13.7% (w/w), was ca. 400 nm in size and had a ζ-potential of −28 mV. NG(S) released PD very slowly at gastric pH and faster but gradually at small intestinal pH. Although NG(S) was easily taken up by the macrophage-like cell line Raw 264.7, it did not decrease cell viability, suggesting that the toxicity of the nanogel was very low. The in vivo evaluation was performed using rats with trinitrobenzene sulfonic acid (TNBS)-induced colitis. NG(S) and PD alone were not very effective at 5 mg PD eq./kg. However, NG(S) at 10 mg PD eq./kg markedly suppressed colonic damage, whereas PD alone did not. Furthermore, thymus atrophy was less with NG(S) than with PD alone. These results demonstrated that NG(S) is very safe, promotes drug effectiveness and has low toxicity. NG(S) has potential as a drug delivery system for the treatment of ulcerative colitis.