Pharmacoscintigraphy

Introduction of new biomedical technology and upgradation of existing ones is constantly required for defence personnel at HA to increase their comfort and efficiency level, and reduce morbidity and mortality. DRDO has introduced nuclear medicine as a potent and advantageous tool in this regard at the national level in general and at global level in some specific areas. This branch of nuclear medicine is called pharmacoscintigraphy. It provides one of the most safe, convincing, quantitative and functional approaches that can be used directly in humans bypassing lengthy and cumbersome conventional pre-clinical or phased clinical trials. Not only it has been used by DRDO in evaluating medical products, but also to develop and clinically evaluate its own products. Fifteen transdermal and many inhalation and gastrointestinal preparations have been made and evaluated by pharmaco-scintigraphy in humans within a period of two years to yield many new products. Pharmacoscintigraphy has also been used to prove the efficacy of ITAD, Anukool I and II, and cold injury ointments (including Aloevera) conclusively.

Besides assisting high altitude medical research, pharmacoscintigraphy has been used by DRDO for designing animal and invitro experiments for development of drug systems. Another use is imaging in patients using radio-labelled drugs and chemicals. Radio-labelled ciprofloxacin (DiagnobactTM), citrate (Diagnomammo) and Glucaric acid radiopharmaceutical cold kits are prime examples of this

activity. These kits have important diagnostic uses. DignobactTM and Glucaric acid radiopharmaceutical kits may also have a role in prognosis of frostbite injury.

               DiagnobactTM Radiopharmaceutical Kit

DiagnobactTM is lyophilised radio-pharmaceutical kit that on reconstitution produces Tc-99m-ciprofloxacin suitable for infection imaging in humans. No bacteria-specific infection imaging radiopharmaceutical was available till date in the country. After seven years of bench-work and clinical trials involving more than 200 patients, it has now been conclusively shown that the indigenous product is superior to internationally marketed product (infectonTM) in terms of technology, ease of use and cost-effectiveness (by a factor of 10). The product has been developed to the level of marketable technology and is now available for routine use.

The radiopharmacy, clinical, administrative and product-development aspects now stand completed. The effort has been widely appreciated in India and have even been noted internationally. It is presently being used by 20 Nuclear Medicine centres across the country.

               DiagnobactDiagnomammo Radiopharmaceutical Kit

Diagnomammo is a lyophilised citrate kit, which produces quality Tc-99m labelled citrate when mixed with requisite amount of Tc-99m-pertechnetate. Tc-99m citrate has been known as an agent for inflammation scintigraphy. It has been modified at INMAS for soft tissue (breast) and bone metastasis imaging. It has also been shown to incorporate irreversibly in the skeleton with a bio-distribution different to that of the conventional bone scan. It can also be used as a tumour-localising agent in palpable breast masses with 87per cent sensitivity and 96 per cent specificity. More than 400 patients suffering from breast cancer/ bone tumour or metastasis have been studied but no adverse reaction of any type has been noticed, fully certifying its safe intravenous administration. It is undergoing phase III clinical trials in 16 Nuclear Medicine centres in India.

               DiagnobactGlucaric Acid Radiopharmaceutical Kit

A cold freeze-dried kit of glucarate consisting of glucaric acid, a reducing agent, a stabiliser, etc. in appropriate proportions has been developed. The kit produces 99mTc-glucarate with more than 99 per cent labelling efficiency, when mixed with requisite amount of 99mTc-pertechnetate. After intravenous administration, presence of a significant amount of radioactivity in kidneys suggests its rapid excretion resulting in low raDIATion dose to the patients. The radiolabel accumulated in the injured tissue as early as 30 minutes post intra venous. administration in the experimental models of thermal and myocardial infarcts. The kit provides quality product in excellent yield and has shelf life of 3 months at 4oC. High avidity of 99mTc-glucarate for infarcted tissue coupled with desirable blood clearance makes it a promising agent for scintigraphic detection of severe acute ischaemic injury with necrosis.