The invention concerns a novel method for preparing an intermediate polyanion for preparing cyclosporin derivatives by treating a cyclosporin with a hexamethyldisilazane metal salt, optionally in the presence of a metal halide. Layer 3 packets are used to encapsulate layer two packets. Similarly, transition metals such as copper may be added to an activated carbon in a salt form in addition to whatever is already present therein as impurities. The bitmap is partitioned into single IO operations.