You could use dexlib2 to load the dex file, remove the classes you're not interested in, and then build a new dex file
int api = 19;
DexFile dexFile = DexFileFactory.loadDexFile(dexFilePath, api);
List<ClassDef> classes = new ArrayList<ClassDef>();
for (ClassDef classDef: dexFile.getClasses()) {
if (!classDef.getType().startsWith("Landroid/support/")) {
classes.add(classDef);
}
}
dexFile = new ImmutableDexFile(classes);
DexFileFactory.writeDexFile(dexFilePath, dexFile);