The present invention relates to compounds of formula (I): wherein R.sup.v, R.sup.1, R.sup.2, R.sup.x, R.sup.y, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.z and v are as defined within; pharmaceutically acceptable salts, solvates, solvates or such salts and prodrugs thereof and their use as ileal bile acid transport (IBAT) inhibitors for the treatment of hyperlipidaemia. Processes for their manufacture and pharmaceutical compositions containing them are also described.