A modified release composition comprising tacrolimus releases less than
20% w/w of the active ingredient within 0.5 hours when subjected to an in
vitro dissolution test using USP Paddle method and using 0.1 N HCl as
dissolution medium and has increased bioavailability by effectively
reducing or even avoiding the effects of CYP3A4 metabolism. The modified
composition may be coated with an enteric coating; and/or may comprise a
solid dispersion or a solid solution of tacrolimus in a hydrophilic or
water-miscible vehicle and one or more modifying release agents; and/or
may comprise a solid dispersion or a solid solution of tacrolimus in an
amphiphilic or hydrophobic vehicle and optionally one or more modifying
release agents.