Abstract
Objective: The objective of this study was to optimize the formulations of antifibrotic tetrandrine beads using alginate and various concentrations ofhydroxypropyl methylcellulose (HPMC) and chitosan.Methods: Beads were formulated with six (F1–F6) concentrations of polymer and were then characterized using scanning electron microscopy,differential scanning calorimetry, and X-ray diffraction; these beads were used for measurements of moisture contents, swelling, and in vitro drugrelease.Results: Beads with the highest concentrations of HPMC and chitosan produced the highest entrapment efficiencies of 49.83% and 50.71%,respectively. Moreover, drug release under stomach conditions (HCl pH 1.2 medium) was restricted to 75.01%, 61.01%, 51.86%, 74.84%, 66.00%,and 41.63% with increasing HPMC and chitosan concentrations (F1–F6, respectively).Conclusion: Beads of all formulations showed inadequate retention of tetrandrine under pH conditions of the upper gastrointestinal tract and wouldlikely be unsuccessful as colon-targeted dosage forms.
Highlights
Colon-targeted drug delivery was previously used to advance therapy for localized disease and to minimize the side effects of drugs in the gastrointestinal tract [1]
Tetrandrine is an antifibrotic agent for the treatment of intestinal fibrosis, which is characterized by excessive deposition of the extracellular matrix under conditions of ulcerative colitis and Crohn’s disease [7]
Patients with fibrosis who were not effectively treated with systemic immunosuppressants benefited from drugs with localized effects [9], and in another study, antifibrotic site-directed effects of tetrandrine were achieved by targeting to the colon [10]
Summary
Colon-targeted drug delivery was previously used to advance therapy for localized disease and to minimize the side effects of drugs in the gastrointestinal tract [1]. These systems were designed to reach the colon with minimal release of enzyme- and pH-sensitive drugs in the upper gastrointestinal tract [2]. These drug delivery systems should achieve long retention times [3], robustness to unique pH conditions [4], decreased doses and side effects, and increase bioavailability, especially for drugs with low absorption [5]. Patients with fibrosis who were not effectively treated with systemic immunosuppressants benefited from drugs with localized effects [9], and in another study, antifibrotic site-directed effects of tetrandrine were achieved by targeting to the colon [10]
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