You are allowed to purchase up to a three-month supply of prescription drugs in Mexico for your personal use provided it is not a controlled substance. Technically you need a prescription from an American or Mexican doctor. Revolution in Tijuana is no longer the main tourist and business area. As you pass the first revolving gate to cross the border, stay to the right and you'll pass through the second revolving gate in about 100 yards. As you pass through the second gate, there is a large business square, which includes about 20 drugstores.
Most people go to each one and bargain for the lowest price.
Eli Lilly makes it but the writing is in Spanish. Follow the link for details. I called Lilly and they recommended the 29 gage. They said the reason was that the 30 gage could become clogged. You can also purchase syringes Hocks .