Kimia Radiofarmasi Radiochemical atau senyawa radiokimia adalah senyawa kimia yang mengadung atom radioaktif di dalam struktur kimianya. Senyawa radiokimia akan menjadi radiofarmaka (radiopharmaceutical) bila telah teruji di manusia untuk tujuan penggunaannya berdasarkan persyaratan yang ditetapkan oleh Badan POM kalau di Indonesia atau oleh US Food and Drug Administration (FDA) kalau di Amerika Serikat, dan diketahui aman dan efektif untuk tujuan diagnosa dan terapi penyakit. dalam bentuk sedian oral seperti kapsul dan larutan dengan cara inhalasi sebagai gas dan aerosol dengan berbgai rute injeksi, paling sering secara intravena Bentuk fisiko-kimia radiofarmaka mulai dari senyawa unsur sederhana sampai molekul bertanda atom radioaktif yang kompleks, unsur-unsur sel darah, dan partikel yang kemudian diberikan ke pasien: :

Radiofarmaka hampir semua radiofarmaka merupakan senyawa organik atau anorganik sederhana yang memiliki komposisi tertentu. Radiofarmaka jenis ini dapat dikelompokkan sebagai radiofarmaka tidak spesifik substrat karena tidak berpartisipasi dalam reaksi kimia spesifik. ada beberapa radiofarmaka yang terbentuk dari molekul makro (macromolecules), seperti antibodi monoklonal (monoclonal antibody) atau fragmen-fragmen antibodi, yang ditandai tidak secara stokiometri dengan suatu radionuklida. Radiofarmaka jenis ini disebut radiofarmaka spesifik substrat, karena harus berpartisipasi dalam reaksi kimia spesifik atau mengambil peranan dalam suatu interaksi ligand spesifik- substrat.

Formulasi dan labeling Formulasi Ligand + reduktor + anti oksidant + stabilizer Kit Radiofarmaka Labeling Radionuklida + Kit Radiofarmaka Radiofarmaka

Preparation of Radiopharmaceutical 1- Sterilization: - Radiopharmaceutical preparations intended for parenteral administration are sterilized by a suitable method. - Terminal sterilization by autoclaving is recommended for heat stable products - For heat labile products, the filteration method is recommended. 2- Addition of antimicrobial preservatives: - Radiopharmaceutical injections are commonly supplied in multidose containers.

Preparation of Radiopharmaceutical : Preservatives are added to many radiopharmaceuticals or labeled compounds in order to preserse their integrity and efficacy. In many case a preservative can function as stabilizer, an antioxidant or bactericidal agent Preservatives must not react with any ingredient of radiopharmaceutical preparation.

3- Compounding: compounding can be as simple as: - adding a radioactive liquid to a commercially available reagent kit as complex as: 1- the creation of a multi-component reagent kit N.B. Kit for radiopharmaceutical preparation means a sterile and pyrogen-free reaction vial containing the nonradioactive chemicals [e.g., complexing agent (ligand), reducing agent, stabilizer, or dispersing agent] that are required to produce a specific radiopharmaceutical after reaction with a radioactive component. 2- the synthesis of a radiolabeled compound via a multi-step preparation process.

3- Compounding: The process of compounding radiopharmaceuticals must be under the supervision of recognized nuclear physician or a radiopharmacist. STABILITY OF COMPOUNDED PREPARATIONS All extemporaneously compounded parenteral radiopharmaceutical preparations should be used no more than 24 hours post compounding process unless data are available to support longer storage.

Radiation shielding: Adequate shielding must be used to protect laboratory personnel from ionizing radiation.

Pro-Tec II Syringe Shield Guard Lock PET Syringe Shield Color Coded Vial Shields Pro-Tec V Syringe Shield

Vial Shield Unit Dose Pig High Density Lead Glass Vial Shield Sharps Container Shields

Radiation shielding: Alpha and beta radiations are readily shielded because of their limited range of penetration. The alpha particles are mono-energetic and have a range of a few centimetres in air. aluminium, glass, or transparent plastic materials, are used to shield sources of beta radiation. Gamma radiation is commonly shielded with lead and tungsten.