It depends on you, how determined you are to get it done, how conversant you are with the topic, how unique (or technical) you seem the topic is to you and how easily accessible your research materials are. With the internet, the final factor seems the easiest. I have published over 2,000 articles across 7 article directories and while some take me 3 weeks to research and publish, some will take me 10 minutes to just sit down in from of my keyboard and start typing!
As a medical personal, I find writing medical articles quite easy. I just consult my notes and that's it.... Before you know it, I select a topic and I am writing 2, 3 or even 4 to 5 articles about it! So, it depends on these factors but over all, your quest and determination to make the article a reality will speed up the time you would need to publish it.