Designing and Developing Green Drug Delivery Systems: From natural bioactives to sustainable therapeutics

Abstract: 

The growing need for effective and sustainable therapeutics is driving our interest in green approaches to drug delivery. Natural bioactive compounds, innovative delivery systems and targeted therapeutic strategies offer opportunities to improve the efficiency of the environment while reducing environmental impact. This Q&A will dive into emerging approaches, current challenges and future opportunities for developing sustainable and patient-focused drug delivery systems.

1. What is driving the growing interest in green drug delivery systems, and how do you define “green” in the context of pharmaceutical development and therapeutics?

I believe that the growing interest in green drug delivery systems reflects an essential change in our thinking about pharmaceutical innovation. Conventionally, the development of medicines accounted majorly for their safety, stability, effectiveness, and commercial viability. These remain priorities with an equally important parallel dimension about the environmental cost of producing and using these medicines. 

Development of any pharmaceutical can consume significant amounts of water, energy, solvents, excipients, and other resources, while manufacturing and disposal can also generate waste and pharmaceutical residues that may enter the environment.

Thus, for me, “green” pharmaceutical development means designing medicines and delivery systems with sustainability integrated right from the very beginning. Selecting a safer and preferably renewable materials, reducing hazardous solvents, minimising waste, lowering energy consumption, developing efficient manufacturing processes, and considering biodegradability and end-of-life disposal.

However, it is important to note that green does not simply mean ‘natural’, because any naturally derived material can still leave a significant environmental footprint from its extraction, purification, transportation, or processing which might be resource intensive. Ultimately, a truly green drug delivery system should aim for therapeutic efficacy and patient safety while minimising the environmental impact throughout its entire lifecycle.

2. Natural bioactive compounds are increasingly being explored as therapeutic agents. What advantages do they offer, and what are the key challenges in translating their potential into effective drug delivery systems?

Natural bioactives have been traditionally derived from plants, marine organisms, microorganisms, fungi, and other biological sources have served as an extraordinary resource for drug discovery with enormous chemical diversity, and ability to interact with multiple molecular targets. They have demonstrated a wide range of activities, including anticancer, anti-inflammatory, antimicrobial, antioxidant, immunomodulatory, and neuroprotective effects. From my perspective, marine bioactives are particularly exciting and offer unique chemical scaffolds synthesized in stressed underwater condition and inspires new therapeutic approaches.

The primary challenge here however is that biological activity alone does not make a chemical moiety a drug.

Many of these natural compounds have limitations such as poor water solubility, chemical instability, low permeability, rapid metabolism, or inadequate absorption. Their nature can also vary according to their geographical location, environmental conditions, harvesting, seasonality, and extraction methods making the standardisation process critical. We need to know what exactly we are delivering, at what concentration, with what purity and reproducibility.

However, the challenge is to move from “interesting biological activity” to translational therapeutics which is reproducible, scalable, and pharmacologically active. This requires collaboration across the domains from natural-product chemistry, pharmacology, formulation science, toxicology, biotechnology, and clinical research.

3. How can innovative drug delivery technologies improve the bioavailability, stability, targeting, and therapeutic efficacy of natural bioactives?

Advanced drug delivery can be transformative for natural bioactives, as in most of the cases their biological potential is not fully understood because it cannot only reach its target in sufficient concentration nor can remain there for sufficient time to produce the desired effect. These limitations can be addressed through drug delivery technologies such as nanoparticles, liposomes, micelles, nanoemulsions, lipid-based carriers, polymeric systems, hydrogels, and controlled-release platforms. While encapsulation protects sensitive molecules against degradation from oxidation, hydrolysis, light, and enzymes; lipid-based systems help in improving the absorption of poorly water-soluble compounds, while polymeric systems can provide sustained or controlled release.

I see drug delivery as a means of engineering the pharmacological action of a therapeutic molecule, which can potentially control the journey of molecule for its release profile and bioavailability. This is important specifically for natural bioactives because it’s the formulation science which can sometimes make the difference for a promising molecule becoming a viable therapeutic candidate.

4. What emerging materials or delivery platforms do you see as particularly promising for developing environmentally sustainable drug delivery systems?

I am intrigued by the biodegradable and naturally derived materials, including polysaccharides such as chitosan, alginate, cellulose derivatives, starch, and other biomaterials. Marine-derived biomaterials and polymers are highly promising for encapsulation, controlled release, and tissue interaction. There are also interesting developments in biodegradable lipid and polymeric nanoparticles, hydrogels, and stimuli-responsive delivery platforms.

But I would caution against evaluating sustainability based on the origin of a material alone, since “natural” material is not necessarily sustainable, just as a synthetic material is not necessarily environmentally harmful. The complete lifecycle of the material should be examined from its origin to production, resources it consumes and how it gets modified, its behaviour in the body, and finally its fate after disposal. The future lies in safe-and-sustainable-by-design materials, where biological performance and environmental considerations are incorporated simultaneously.

5. How can researchers balance therapeutic performance with environmental considerations when selecting excipients, polymers, solvents, and other materials used in drug delivery?

The incorporation of sustainability into formulation decisions from an early stage rather than treating it as an additional criterion at the end can be pivotal. Right from selection of a material, considering its toxicity, biodegradability, renewability, resource requirements, manufacturing complexity, scalability, cost, and therapeutic functionality should be considered. 

Solvents deserve considerate attention due to their substantial environmental footprint in pharmaceutical manufacturing. Investigation of scientifically and technically feasible, safer alternatives, including water and other relatively benign solvents should be conducted. At the same time, compromising a formulation’s quality simply to achieve a superficial definition of “green” should be avoided, at the same time patient safety, efficacy, stability, and reproducibility remain non-negotiable.

Thus, I strongly support a multidimensional evaluation framework for the assessment of therapeutic performance, safety, manufacturing feasibility, cost, and environmental impact all together.

6. What role can nanotechnology and advanced targeted delivery systems play in reducing drug dosage, minimising systemic side effects, and improving patient outcomes while supporting sustainability?

Nanotechnology provides an important opportunity to improve the drug delivery efficiency. For e.g. If we can preferentially deliver a drug to its intended site of action, we may be able to achieve the desired pharmacological effect with a lower dose and/or reduced frequency of administration, which can potentially minimise systemic exposure and associated side effects.

Targeted delivery is particularly important in diseases such as cancer, where the therapeutic window can be limited by toxicity to healthy tissues. Similar challenges exist in neurodegenerative diseases, where drug delivery to the central nervous system remains complex.

From a sustainability perspective, using a smaller quantity of an active pharmaceutical ingredient to achieve the same or better therapeutic efficacy could potentially reduce manufacturing, transportation, and pharmaceutical waste. However, nanotechnology must itself be sustainable, as we need to understand the biodegradation, biodistribution, toxicity, and environmental fate of nanomaterials. Ideally, we should have a goal of precision nanomedicine using safe, biodegradable, and environmentally responsible materials.

7. Many natural compounds face challenges such as poor solubility, instability, and limited absorption. What innovative approaches are being explored to overcome these barriers?

We are exploring nanoemulsions, liposomes, solid lipid nanoparticles, nanostructured lipid carriers, polymeric nanoparticles, micelles, phytosomes, cyclodextrin complexes, amorphous solid dispersions, and self-emulsifying delivery systems for improving apparent solubility, protecting the unstable molecules, facilitate absorption, and provide controlled release.

We are also interested in combination delivery of natural bioactives with another therapeutic or synergistic agent, which could increase the efficacy and potentially reduce the required dose in suitable cases. Stimuli-responsive systems towards biological cues such as pH, enzymes, or redox conditions are another exciting direction, which respond and release the therapeutic preferentially under specific conditions. Overall, the broader objective remains to achieve spatiotemporal control of drug delivery for the right amount at the right location at right time.

8. How important is targeted drug delivery in developing patient-focused therapeutics, and how can green approaches contribute to more precise treatment?

Patients can differ in disease biology, metabolism, drug response, and tolerance. As modern medicine is moving increasingly toward precision and patient-centred treatment, targeted delivery capable of concentrating a drug at the diseased site may improve the therapeutic index by increasing efficacy while reducing unnecessary exposure to healthy tissues.  

Green approaches can be useful by encouraging efficient rather than excessive drug delivery. Biodegradable carriers, naturally derived targeting components, and stimuli-responsive systems can potentially provide greater precision without creating unnecessary material burdens. 

I see sustainability and precision as complementary objectives. The more efficiently we deliver a therapeutic, the less unnecessary drug and material we may need to use.

9. What are some of the major challenges involved in scaling up and commercialising sustainable drug delivery technologies developed at the laboratory or research level?

This is one of the biggest gaps between academic innovation and commercial translation. A formulation works excellent at laboratory scale and may behave very differently when attempted for scale up at industrial scale. Several issues may arise with reproducibility, raw-material variability, particle characteristics, sterilization, stability, quality control, packaging, and cost. Natural materials introduce additional variability, making sourcing and standardisation particularly critical.

Therefore, researchers need to think about scalability much earlier in the development process, and ask themselves whether not only a formulation works, but it can be manufactured consistently, economically, and sustainably. Not only strong collaboration between academia and industry is essential; but also, involvement of engineers, formulation scientists, pharmacologists, clinicians, regulatory experts, and manufacturing specialists before a technology reaches the final stages of development is equally important.

10. How can the pharmaceutical industry assess the environmental footprint of a drug delivery system across its entire lifecycle?

Life-cycle assessment (LCA) is an important tool for assessing the environmental footprint systematically. The evaluation of the environmental impact of raw-material sourcing, extraction or synthesis, transportation, formulation, manufacturing, packaging, distribution, clinical use, and disposal needs to be done. The parameters for energy consumption, water usage, greenhouse-gas emissions, solvent use, waste generation, resource depletion, and toxicity should be included, and the sustainability claims should increasingly be supported by quantitative evidence rather than assumptions. 

The lifecycle approach allows us to compare alternative formulations objectively and identify where the largest environmental impacts occur. It can also help researchers optimise processes even before they stick to expensive industrial systems.

11. Could green chemistry principles significantly reshape the way drug delivery systems are designed and manufactured? What changes do you believe are most necessary?

Yes. I believe green chemistry can fundamentally influence the future of pharmaceutical formulation and manufacturing. We need to reduce waste, use safer chemicals and solvents, improve reaction efficiency, lower energy requirements, and design processes that avoid unnecessary chemical transformations and purification steps.

Where appropriate, process intensification, continuous manufacturing, solvent recovery, and renewable feedstocks can further improve sustainability.

But the most important change is conceptual, wherein sustainability needs to become a design parameter rather than a post-development consideration. With incorporation of green chemistry principles at the beginning of drug and delivery-system development, there will be greater freedom to redesign the process. Retrofitting sustainability into an established manufacturing process is difficult.

12. What regulatory and safety considerations need to be addressed before natural bioactive-based and environmentally sustainable delivery systems can achieve wider clinical adoption?

The fact that a compound is natural or a formulation is environmentally friendly does not eliminate the need for comprehensive safety evaluation and regulatory rigor is essential. These natural bioactives need well-defined identity, purity, potency, pharmacokinetic and pharmacodynamic profiles, contaminant assessment, and appropriate toxicological studies. For advanced delivery systems, we need detailed information about particle size, morphology, surface characteristics, stability, degradation, biodistribution, and potential accumulation.

Any formulation cannot become a reliable therapeutic if its composition varies significantly from one batch to another emphasising the importance of manufacturing consistency. Regulatory frameworks continue to evolve as increasingly sophisticated delivery systems are emerging. The central principle should be having the sustainability approach complementing the pharmaceutical safety and efficacy requirements and never replacing them.

13. Looking ahead, how do you see artificial intelligence, computational modelling, or other emerging technologies accelerating the design and optimisation of green drug delivery systems?

Artificial intelligence has enormous potential to accelerate formulation development. While machine-learning models can integrate large datasets involving chemical structures, physicochemical properties, biological activity, toxicity, formulation composition, and processing conditions, computational modelling can help us optimise parameters such as particle size, drug loading, release kinetics, stability, and targeting. These emerging technologies can help us in prediction of promising formulations before conducting extensive experimental studies. 

From a sustainability perspective, this is particularly important as with better and efficient prediction the unnecessary experiments, material consumption, solvent use, and development time burden can be reduced drastically. I envision an AI-assisted formulation development cycle, in which computational predictions guide the experiments, experimental data refine the models, and the improved models guide the next round of experiments. This way the integration of computational and experimental work could significantly accelerate the development of greener and more effective delivery systems.

14. What are the most important breakthroughs you expect in sustainable drug delivery over the next five to ten years, and what will it take to move the field from promising research to widely adopted therapeutics?

I am expecting significant advancement over the next five to ten years in biodegradable nanocarriers, smart and stimuli-responsive systems, marine- and plant-derived biomaterials, precision delivery, along with AI-driven formulation design. I understand that the environmental metrics will become increasingly integrated into pharmaceutical research and manufacturing decisions. 

However, I also believe that the future will not be defined by just one revolutionary material or one delivery technology. The real breakthrough will only happen by the emergence of a systems-level approach to sustainable therapeutics. The need to bridge the drug discovery, formulation, manufacturing, clinical performance, economics, and environmental impact is much more pressing than ever rather than treating them as separate stages. 

The medicine of the future should be fundamentally interconnected for human health to planetary health. I envision that the next generation therapeutics will be safe, effective, precise, affordable, scalable, patient-focused, and environmentally responsible. Never than ever before, we have now an opportunity to redefine pharmaceutical innovation by bringing together the chemical diversity of natural products, the precision of advanced drug delivery, the principles of green chemistry, and the predictive power of artificial intelligence. Collectively, the goal remains to design better medicines from the outset—medicines that work better for patients while placing a smaller burden on the planet.