One should observe the taharah of the clothes during the prayer as the prayer is void with najis clothes. With respect to wudhu, you can perform the prayer at a time the urine is not released from you, even by delaying it to the end of the prescribed time - but not beyond it - and even if you shorten the prayers by omitting the second chapter after al-Fatiha and by omitting the recommended acts of the prayer. If this is not possible, then it is permissible to offer the prayer even with the release of the urine but one should join the Dhuhr and Asr prayers with one wudhu, and similarly the Maghrib and Isha prayers with one wudhu.
