Is it okay if my powder azithromycin is lumpy?

I was given one dose of azithromycin in powder form. I was supposed to mix it with 2 ounces of water. I did that and mixed it up but there were still some clumps of the powder that wouldn't really break up. I drank it all anyways. I'm not too worried about it but this shouldn't mess with the effectiveness of the antibiotic should it?