A Freeze-Dried Kit for the Preparation of 188Re-HEDP for Bone Pain Palliation: Preparation and Preliminary Clinical Evaluation

[sup]188Re-HEDP is an established radiopharmaceutical used for pain palliation in patients with osseous metastasis. Considering commercial availability of [sup]188W/[sup]188Re generator, the accessibility to a lyophilized kit would make preparation of this radiopharmaceutical feasible at the hospital radiopharmacy having access to a generator. A protocol for the preparation of a single-vial lyophilized hydroxyethane 1,1-diphosphonic acid (HEDP) kit was developed and its consistency was checked by preparing six batches. Each sterile lyophilized kit prepared as per the protocol contained 9 mg of HEDP, 3 mg of gentisic acid, and 4 mg of SnCl[sub]2.2H[sub]2O. Randomly selected kits from all six batches were subjected to thorough quality control tests that were passed by all batches. [sup]188Re-HEDP could be prepared by addition of 1 mL of freshly eluted Na[sup]188ReO[sub]4 (up to 3700 MBq) containing 1 μmol of carrier ReO[sub]4[sup]- (perrhenate) and heating at 100°C for 15 minutes. [sup]188Re-HEDP with >95% radiochemical purity could be consistently prepared using the lyophilized kits. Sterile [sup]188Re-HEDP prepared using the lyophilized kit was evaluated in patients with osseous metastasis. Post-therapy images of the patient were compared with [sup]99mTc-MDP bone scan and found to be satisfactory. The bone-to-background as well as tumor-to-normal bone uptake ratio was found to be significant. All patients who received therapy reported significant pain relief within a week to 10 days post-administration of [sup]188Re-HEDP.