Be sure you purchase the right product... Lanacane® Anti-Chafing Gel would be a reasonable substitute for Hydropel since it contains: Cyclopentasiloxane, Dimethicone (what percent?) Crosspolymer, Vinyl Dimethicone Crosspolymer, Zea Mays (Corn) Starch.
Hydropel contains 30% dimethicone which is a silcone substance which both reduces friction and acts as a moisture barrier. Hydropel also contains 10% hydrophobic starch to minimize the greasy feeling of its petrolatum base.
Plain Lanacane is a topical anesthetic containing benzocaine, which I'd avoid using on a daily basis as a preventive agent due to this problem: http://www.fda.gov/safety/medwatch/safetyinformation/safetyalertsforhumanmedicalproducts/ucm250264.htm In addition, this version isn't going to do what you want it to.
Also - here is a related BPL post on the topic: http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=33635