DRDO Seeks Indigenous Ca-DTPA and Zn-DTPA Medical Countermeasures for Radiological Emergencies

India is moving to strengthen an unusual but strategically important part of its medical preparedness, with the Defence Research and Development Organisation seeking Indian industry to develop pharmaceutical-grade Calcium-DTPA and Zinc-DTPA formulations for treating certain forms of internal radioactive contamination.

The programme is being pursued through DRDO’s Technology Development Fund, which encourages Indian companies, particularly MSMEs and technology enterprises, to develop critical capabilities required by the country’s defence and strategic sectors.

Unlike protective suits, radiation detectors or decontamination equipment, Ca-DTPA and Zn-DTPA work inside the human body. They are specialised medicines used when certain radioactive elements have entered the body through inhalation, ingestion, wounds or other pathways.

This distinction is important because radioactive exposure and radioactive contamination are not the same thing. A person can be exposed to radiation without radioactive material actually entering the body. DTPA treatment is intended for specific cases of internal contamination, particularly involving radioactive isotopes of plutonium, americium and curium.

Once such radioactive material enters the body, some of it can remain in tissues for prolonged periods and continue exposing surrounding cells to ionising radiation. The medical objective is therefore to remove as much of the contaminant as possible before it becomes firmly deposited in organs and bones.

Ca-DTPA and Zn-DTPA belong to a class of compounds known as chelating or decorporation agents. They bind with certain radioactive metals circulating within the body, forming complexes that can then be eliminated primarily through urine.

The treatment does not neutralise radiation itself, nor is it a universal antidote for every radioactive substance. Instead, it accelerates the removal of specific radionuclides from the body and thereby reduces the amount of time those materials remain internally.

The calcium and zinc versions have complementary roles. Ca-DTPA is generally more effective during the first 24 hours following internal contamination, making rapid administration particularly valuable after a confirmed or strongly suspected exposure involving plutonium, americium or curium.

After the first day, Ca-DTPA and Zn-DTPA become broadly comparable in their ability to promote removal of those radionuclides. For continued treatment, Zn-DTPA is commonly preferred because repeated administration of Ca-DTPA can also bind important minerals required by the human body.

This makes the existence of both formulations important for a complete medical-response capability. In a major incident, Ca-DTPA could form part of the initial treatment response, while Zn-DTPA could support subsequent therapy where repeated administration is necessary.

The need for such medicines is unusual, but the situations in which they could become necessary are potentially serious. Internal radioactive contamination can result from accidents involving nuclear or radiological materials, occupational incidents, damaged radioactive sources or deliberate radiological events.

Military and civil emergency planners therefore treat decorporation agents as part of the wider family of medical countermeasures for Chemical, Biological, Radiological and Nuclear emergencies.

India’s expanding nuclear-energy programme makes preparedness for extremely low-probability but high-consequence radiological events increasingly important. The country operates nuclear power stations, research reactors, fuel-cycle facilities and numerous industrial, medical and scientific installations that use radioactive materials under tightly controlled conditions.

The objective of emergency preparedness is not to suggest that such facilities are unsafe. Rather, nuclear safety systems are designed around multiple layers of defence, one of which is ensuring that specialised medical treatments are available if normal safeguards fail.

The same preparedness has strategic relevance for the Armed Forces. Military personnel may potentially be required to operate in environments where radiological contamination has occurred, whether because of an accident, a damaged source or a hostile CBRN event.

Radiation monitoring, protective equipment, decontamination systems and specialised pharmaceuticals therefore form different layers of the same response architecture.

DRDO’s latest programme is particularly significant because it focuses on converting the medical requirement into an indigenous pharmaceutical manufacturing capability rather than depending solely on overseas sourcing of specialised countermeasures.

The requirement that development take place under Good Manufacturing Practice conditions is central to the project. GMP is the pharmaceutical quality framework used to ensure that medicines are produced consistently, safely and according to controlled manufacturing standards.

Developing the active pharmaceutical chemistry alone would therefore not satisfy the requirement. The selected Indian industry partner will need to demonstrate that Ca-DTPA and Zn-DTPA can be formulated, manufactured and quality-controlled through processes appropriate for pharmaceutical deployment.

This takes the project beyond laboratory chemistry and into the much more demanding field of regulated drug production.

A medical countermeasure intended for emergency stockpiles must remain stable during storage, meet strict purity requirements and provide predictable dosing when urgently required. Its manufacturing process must also be reproducible so that additional quantities can be produced when stocks need to be replenished or rapidly expanded.

For India, domestic manufacture provides an additional strategic benefit because radiological countermeasures are specialised products with relatively limited routine commercial demand. Such medicines may not always be readily available in large quantities through conventional pharmaceutical supply chains.

During a major emergency affecting more than one country, international demand for specialised drugs could also increase rapidly. Having qualified domestic production capability can therefore provide greater control over emergency reserves and supply-chain continuity.

The project also represents an interesting convergence between India’s defence research ecosystem and its pharmaceutical manufacturing strength. India is one of the world’s largest producers of medicines, with extensive capabilities in formulation development, sterile manufacturing, active pharmaceutical ingredients and regulated pharmaceutical exports.

Applying this industrial capacity to specialised strategic medicines provides another dimension to defence indigenisation. Self-reliance does not consist only of producing missiles, aircraft, radars and armoured vehicles. It also requires domestic control over medical systems needed to protect personnel operating those technologies.

Ca-DTPA and Zn-DTPA are a particularly good example because their importance becomes apparent only under rare emergency circumstances. They may remain unused for long periods, yet their availability can become critical if internal contamination occurs.

International medical guidance recognises both compounds as treatments for internal contamination involving plutonium, americium and curium. Once administered, the DTPA molecule binds these radioactive elements and helps accelerate their elimination through the kidneys.

Treatment is most effective when begun quickly because radioactive substances become more difficult to remove as they move from the bloodstream into tissues. Even after several days or weeks, however, DTPA may still help remove some remaining contamination, depending on the radionuclide burden and individual circumstances.

Medical professionals may monitor urine, blood and other biological samples during treatment to determine how effectively the radionuclide is being removed and how much contamination remains within the body. Treatment duration consequently depends on the amount of internal contamination and the patient’s response.

DTPA should not be confused with potassium iodide, another medicine commonly associated with nuclear emergencies. Potassium iodide works only against radioactive iodine by saturating the thyroid with stable iodine and reducing uptake of the radioactive form.

DTPA addresses an entirely different category of contamination involving certain heavy radioactive metals. A comprehensive radiological medical-response system therefore requires several countermeasures matched to different radioactive substances rather than relying on one universal drug.

This is one reason DRDO’s programme deserves attention. The development of Ca-DTPA and Zn-DTPA indicates a move towards building a more specialised domestic portfolio of radiological medical countermeasures.

The initiative could also create technological capability within Indian pharmaceutical companies that extends beyond the immediate defence requirement. Producing chelating agents under controlled GMP conditions requires expertise in formulation chemistry, sterile processing, analytical testing, stability studies and regulatory-quality manufacturing.

These capabilities could subsequently support other specialised emergency medicines and strategic pharmaceutical products.

The Technology Development Fund provides the mechanism through which this capability can be created in partnership with Indian industry. DRDO uses the TDF programme to move identified defence requirements into domestic industrial development rather than attempting to manufacture every technology within government laboratories.

Under the wider TDF framework, Indian industry can receive substantial government support towards eligible development costs, while the programme seeks to build domestic intellectual property and production capacity for technologies that might otherwise remain dependent on imports.

The Ca-DTPA and Zn-DTPA project is particularly notable because it demonstrates how broad the concept of defence technology has become. A strategically important indigenous product need not always be a weapon, sensor or electronic system. It can also be a specialised medicine stored quietly in a medical reserve until the day it may be urgently required.

India’s continuing expansion in nuclear energy, advanced research and strategic infrastructure makes preparedness for radiological emergencies increasingly relevant. The probability of serious internal contamination incidents remains low because nuclear and radiological facilities operate under multiple regulatory safeguards, but effective emergency planning must account for consequences rather than probability alone.

Indigenous pharmaceutical manufacturing can provide an additional layer of resilience by ensuring that critical countermeasures are available without complete dependence on foreign supply.

The programme illustrates an often-overlooked side of defence self-reliance: protecting soldiers, emergency responders and potentially civilians not only with better equipment, but also with specialised medicines designed for the most demanding emergencies.

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