This recent confirmation from Google is a bit common sense, but just in-case: don’t use commas, semicolons, spaces, quotes, and other special characters in your URLs. John Mueller from Google stated in a Google Webmaster Help thread:
I generally recommend avoiding special characters like commas, semicolons, colons, spaces, quotes etc. in URLs, to help keep things simple. URLs like that are often harder to automatically link (when someone posts in a forum or elsewhere), and hard for us to recognize correctly when we parse text content to try to find new URLs. When they’re linked normally or submitted through a sitemap directly, they work as expected. However, when we try to recognize the URL in something that we crawl as a HTML or a text page, then we’ll probably “guess” them wrong — which is fine, since we’ve probably already seen them through the normal links & sitemap usage.
In the end – try to avoid using any special characters. If you absolutely must use them – try to use 301 redirects to a more traditional URL.