Described are sustained-release solid dosage forms of epigallocatechin gallate (EGCG) or aminosterol compositions. In one aspect of the invention the sustained-release solid dosage forms of EGCG or an aminosterol are capsules comprising a plurality of coated solid particulates. Another aspect of the invention relates to methods of inhibiting, ameliorating, reducing the likelihood of, delaying the onset of, treating or preventing an amyloid disorder, comprising the step of administering to a subject in need a therapeutically effective amount of the solid dosage form. In certain aspects, the amyloid disorder is Parkinson's Disease.