Oral Formulation of 5-Aminosalicylic Acid-Hemoglobin Bio-Adhesive Nanoparticles Enhance Therapeutic Efficiency in Ulcerative Colitis Mice: A Preclinical Evaluation

Abstract The oral formulation design for colon-specific drug delivery brings some therapeutic benefits in the ulcerative colitis treatment. We recently reported the specific delivery of hemoglobin nanoparticles-conjugating 5-aminosalicylic acid (5-ASA- HbNPs) to the inflamed site. In the current study, the in vivo evaluation of 5-ASA from its bio-adhesive nanoparticles shows the greatly long residence time of 5-ASA and complete support of the colon as compared with free 5-ASA due to the suitable mucoadhesive property to traverse the mucus layer and accumulate within the mucosa is a vital process. Furthermore, the UC model mice exhibited notably reduced indexes of disease activity; along with decreased ratios of colon weight/length in the group treated with 5-ASA-HbNPs. This group received a one-thousandth of the standard dosage of 5-ASA amount (50 μg/kg). While, a similar result was observed for a considerable quantity of free 5-ASA (50 mg/kg), confirming the therapeutic efficacy of this formulation in vivo. Furthermore, microscopic images of histological sections of the extracted colons demonstrated that the 5-ASA-HbNPs and 5-ASA groups displayed instances of inflammatory damage within the colon. However, in comparison to the control group, the extent of this damage was relatively moderate, suggesting 5-ASA-HbNPs improved therapeutic efficacy with the lower dosage form.