 23. Women must be of non-childbearing potential i.e. either postmenopausal or documented hysterectomy - tubal ligation is not sufficient. For the purposes of this study, post menopausal is defined as being amenorrhoeic for greater than 2 years with an appropriate clinical profile, e.g. age appropriate, history of vasomotor symptoms. Postmenopausal status will be confirmed by serum or urine FSH and oestradiol concentrations at screening, if appropriate. Surgical sterility will be defined as females who have had a hysterectomy andor bilateral oophorectomy. 