Synthesis and characterization of furosemide‐loaded sericin/alginate beads subjected to thermal or chemical cross‐linking for delayed and sustained release

Modified‐release systems have been evaluated as an option to formulations that employ the conventional delivery system and, therefore, may present side effects and reduced therapeutic efficacy. In general, it is more convenient to modify the release of existing drugs to overcome their drawbacks, since developing a new drug can be a quite expensive and time‐consuming process. Furosemide, a drug for hypertension treatment, when administered in the conventional form, can cause inconvenience to patients due to short and intense periods of diuresis and the need for multiple daily administrations due to its short half‐life. In order to modify its release, in the present work, furosemide was successfully incorporated into sericin/alginate matrix prepared by ionic gelation and modified by thermal or covalent cross‐linking, through the addition of proanthocyanidin, achieving high incorporations rates. This polymeric matrix provided a delayed and sustained release form for furosemide, which could improve patients' compliance to treatment and decrease its side effect. Furosemide release study demonstrated that the cross‐linking method affects the amount of dosage release and does not affect the release time, but the presence of sericin does. scanning electron microscopy, X‐ray diffraction, and FT‐IR analyses confirmed furosemide incorporation. The drug thermal stability was not affected by its incorporation and the particle size was considered suitable for multiparticulate system.