how to adjust the horizontal gap between string with Drawing String Objects of NSString on iphone

Question

Is there any api to adjust the horizontal gap between strings .I use the code

- (void)drawRect:(CGRect)rect {
      hello =@"this is a test string string string string string string";
      UIFont *hfont = [UIFont fontWithName:@"Arial" size:18];
      [hello drawInRect:self.bounds withFont:hfont ];
}

self is a uiview .it appear that the sentence was break into two lines .but at the end of the first line there is some space between the last character and the edge of view. counld i eliminate the space by adjustment of the horizontal gap, and how?