Sarasota County is a big step closer to a total ban of synthetic drugs. The drugs, many of which mimic the appearance of marijuana, are called a public health hazard by federal officials, and go by names such as “K2” and “Spice.”The commission voted unanimously yesterday to schedule a public hearing in February, which would lead to an outright ban on designer drugs. A recent survey showed that 21.7 percent of high school students in the county have used synthetic marijuana.