Interesting question. As a background, Dr. Kolluru is referring to a chitosan-laced chewing gum that can bind salivary phosphate. Chitosan comes from chitin, which is from the skeleton of crustaceans. Gum laced with chitosan can bind salivary phosphate, which has been shown in only one study (JASN 2009 20(3): 639 | http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2653679/#!po=34.3750) to lower serum phosphorous. Keep in mind that in this study, n = 13 and all patients were taking both the chitosan-gum and sevelamer orally.
Given your patients intolerance to oral binders (as a result of their gastric bypass), a study that analyzes chitosan **monotherapy** would be most valuable. I do not believe such a study has been published.
A 2011 study randomized patients to one of 3 arms: 1) placebo gum, 2) 20 mg of chitosan-laced gum, and 3) 60mg of chitosan-laced gum. I do not believe these patients were given oral phosphate binders. However I was not able to find the results of this study, despite being completed in April 2011 (http://clinicaltrials.gov/ct2/show/study/NCT01341691).
A company out of Maryland sells Rena-Gum, whose active ingredient is chitosan. They quote only 2 studies on their website as proof that their gum works. A 4oz bottle (30 pieces) costs $15. Naturally, I cannot recommend that you advocate it for your patients but it is something you and your patients can consider (http://renagum.com).
Have you tried different oral binders? Perhaps the powdered binders will be more palatabe than the pills. Of course, if serum phosphate is a big concern, would a home therapy like home hemo or PD be indicated and appropriate for your patients? Since phosphorous removal is proportional to diffusion time, increasing the frequency of dialysis (through a home therapy) may provide some improvement.