Trehalosomes: Colon targeting trehalose-based green nanocarriers for the maintenance of remission in inflammatory bowel diseases

Abstract

The use of non-steroidal anti-inflammatory drugs (NSAIDs) in inflammatory bowel diseases (IBDs) are contradictory between their beneficial effect in alleviating inflammation, and injurious outcomes in aggravating the symptoms of colitis. The study aimed to formulate trehalosomes (THs); innovative green trehalose-based nanocarriers, to alleviate the inflammation symptoms that might be provoked by NSAIDs in IBDs; as trehalose was proved to lighten the inflammation and the oxidative stress response, besides its resistance to the acidic conditions that rises its potentiality as a means for colon targeting. THs were fabricated using L-α-phosphatidylcholine (PL), trehalose, and transcutol, in a single step circumventing the incorporation of any organic solvent and loaded with Tenoxicam (TXM) as a model anti-inflammatory medication. A full 2³ factorial design, using Design-Expert® software, was established to optimize the formulation variables. The optimized formulation composed of trehalose: PL at a weight ratio of 1:1, 377.72 mg transcutol, and sonicated for 4 min, possessed a spherical shape with a size of 268.61 nm and EE% of 97.83% and released 70.22% of its drug content over 24 h. The supreme protective action of TXM loaded THs compared to TXM suspension and drug-free THs was revealed by the suppression of the inflammatory biomarkers and the improved histopathology of the colonic tissue in male New Zealand rabbits. IL-1ß, IL-6, and TNF-alpha levels were notably dampened with TXM loaded THs, and oxidative stress markers, measured as GSH and MDA, were significantly altered. The study indicates the successful role of green THs in colon targeting and its anti-inflammatory characteristics in protecting against possible NSAIDs-driven exacerbation of colitis.

Introduction

Inflammatory bowel diseases (IBDs), namely Crohn’s disease and ulcerative colitis, are chronic and relapsing gastrointestinal inflammatory disorders that affect millions of people worldwide [21], [34], [5]. IBDs are proven to be triggered by a deregulated response of the immune system to the normal non-pathogenic gut microbiome that leads to an intestinal damage [18]. Besides, genetic tendency and environmental risk factors might contribute to the progression of the disease [7]. Ulcerative colitis primarily comprises diffused mucosal inflammation with the involvement of the rectum; due to the release of the inflammatory mediators and the progress of ulceration in the superficial mucosa. Alternatively, in Crohn’s disease, macrophages are aggregated mostly in the terminal ileum to form non-caseating granulomas. Peyer’s patches are the first position to bear mucosal lesions in Crohn’s disease. Crohn’s disease could be differentiated from ulcerative colitis through being patchy and segmental, where the inflammation is typically transmural [43].

Non-steroidal anti-inflammatory drugs (NSAIDs) are used in the treatment of various inflammatory conditions, however, their administration to patients with IBDs should be monitored cautiously to circumvent the probability of exacerbation of the intestinal inflammation. That highlights the need for advanced delivery systems that might decrease the possible undesirable effect of NSAIDs in worsening the intestinal inflammation in patients with IBDs. Nano-drug delivery systems targeting the colon are administered orally in most cases, and they are considered vital tools to cure IBDs [19]. These systems are supposed to get localized in the targeted parts, and hence the efficacy of the therapeutics is enhanced, and the systemic toxicity is minimized [33]. To deliver drugs specifically to the colon, formulations are designed to target pH, transit time, pressure, and microflora [6], where pH-dependent drug delivery is a unique strategy that utilizes acid-resistant polymers, such as Eudragit®, as coatings that are triggered only by colonic pH. Recently, Nutriose®, an indigestible dextrin water-soluble fiber that is stable at low pH, was employed in the fabrication of Nutriosomes [8]. In a parallel line, trehalose is a chemically-unique disaccharide, owing to its resistance to the acidic conditions and the lack of direct intramolecular hydrogen bonding [39]. In addition, trehalose was proved to alleviate inflammation and oxidative stress response, signifying its role in the treatment of chronic diseases that relate to oxidative stress and dysfunction of autophagy [32].

The originality of the present study can be summarized in the ability to formulate trehalosomes (THs) in a single step, adopting a green technique; without the use of any organic solvent, and the incorporation of trehalose for alleviating the possible deterioration that would be exacerbated by NSAIDs. THs are self-assembled nanovesicles fabricated using L-α-phosphatidylcholine (PL), trehalose, and transcutol, and loaded with Tenoxicam (TXM) as a model anti-inflammatory medication. The aqueous phase was charged with a considerable amount of trehalose, as a potential anti-inflammatory adjuvant, and a pH-dependent colon targeting agent. Design-Expert® software was utilized to determine the impact of the selected formulation variables on THs properties, and elect the optimized formulation. In addition, the advanced anti-colitis effect of THs was hypothesized, and to validate the proposed hypothesis, the in vivo outcome of the optimized TXM loaded THs was appraised against TXM suspension and drug-free THs in male New Zealand rabbits with induced colitis; to establish its prophylactic ability. The inflammatory biomarkers; IL-1ß, IL-6, and TNF-alpha, and the oxidative stress markers, GSH and MDA levels were measured to assess the anti-inflammatory response, in addition, a histopathological analysis of the colonic tissue was conducted.