Abstract: The present invention provides compositions and methods for treating lysosomal disorders using a class of substituted imidazole derivatives or compounds.

Abstract: Improved methods are provided for therapeutic and/or preventative treatment to a mammal in which the mammal is protected against the toxicity of active pharmaceutical agents that (i) bind to or are substrates for P-gp, (ii) are taxane analogues, and/or (iii) are inhibitors of tubulin disassembly. Additionally provided are compositions and methods useful for treating cell proliferative disorders. Further provided are methods of increasing the bioavailability of therapeutic and/or preventative treatments in a mammal. Particular embodiments are directed to increasing such bioavailability across the blood-brain barrier.