The Regulatory Landscape of New Health Technologies and Nanotechnologies: The Role of Complexity of Nanosystems.

Herein we present the modern issue of new health technologies that emerge in Medicine and Therapeutics, with regard to their development, regulatory framework, approval, and post-approval monitoring. The European law and legislation distinguish the various subcategories of health technologies in medicinal products, medical devices, biotechnological products, advanced therapy medicinal products, and nanomedicinal products. Each of these categories presents its own distinctive characteristics, based on principles that regard the development technology and intended therapeutic use, and, as a result, is defined by a unique regulatory framework inside the European legislation environment. New health technologies are a key of twenty-first-century knowledge, science, and economy and a part of society growth and economic development, while at the same time they present significant challenges, mainly through matters that regard their safety, efficacy, and value for the public. In this environment, the concept of complexity of living and artificial systems arises, as part of their nature, but also as a perspective that will give answers regarding their dynamic behavior, evolution, and overall quality.

Losartan Interactions with 2-Hydroxypropyl-ß-CD.

Losartan potassium salt (LSR) is a well-known antihypertensive drug with proven beneficial effects on human health. Its formulation with the non-toxic 2-hydroxypropyl-ß-cyclodextrin (2-HP-ß-CD) could improve its pharmacological profile. Thus, its molecular interactions are studied using a combination of Differential Scanning Calorimetry (DSC), Nuclear Magnetic Resonance (NMR) and Molecular Dynamics (MD). First, its complexation is shown through Differential Scanning Calorimetry as lyophilization provided distinct thermal properties in comparison to the mixture. The complexation is further proved by utilizing the chemical shift changes in the complexation and T1 values. Furthermore, the reversible favorable complexation was shown by MD calculations. Such physical chemical properties provide evidence that this formulation must be further explored through biological experiments.

Advanced Health Technologies and Nanotechnologies in Neurodegenerative Diseases.

The fields of medicine and therapeutics have lately turned towards more modern approaches for the therapy of diseases. These approaches have been classified as new health technologies and various issues that regard their development, application in therapy, regulatory framework, approval and post-approval monitoring have emerged. In the European environment, the law and legislation distinguish new health technologies in certain subcategories, namely, medicinal products, medical devices, biotechnological products, advanced therapy medicinal products and nanomedicinal products. Among these strategies, nanomedicine utilizes entities at the nanoscale that exhibit therapeutic effect in various diseases, such as neurodegenerative disorders, through chemical, physical or biological action. Several nanotechnology-based therapies have been authorized until today; however, there is still no marketed nanomedicine for neurodegenerative diseases. Advanced nanotechnological platforms, including the prominent example of stimuli-responsive chimeric/mixed nanocarriers, promise high therapeutic efficacy and safety, through their functional properties and biocompatibility, which come from their composing molecules, self-assembled properties and supramolecular structures. The integration of certain important analytical tools for the study of nanocarriers is also of great importance and may provide knowledge for further development of advanced nanomedicines as well as for their follow-on products, known as "nanosimilars".

Liposomes: Production Methods and Application in Alzheimer's Disease.

Liposomes and lipidic vehicles are nanotechnological platforms that are present in the clinic and industry, with extensive application and much potential in the field of therapeutics. Currently, the obstacles associated with the pathology and physiology of Alzheimer's disease (AD) and neurodegenerative disorders (NDDs) in general have rendered it impossible to find an effective therapy for these conditions. The only achievement of the available drugs and treatments is that they have succeeded in temporarily alleviating the symptoms and assisting patients in carrying on with their activities of daily living, but they do not delay, let alone halt, the progression of the diseases. So far, numerous small drug molecules and biological molecules have failed in clinical trials. Liposomes represent a promising option for drug delivery that have yet to be tested in clinical trials. They are manufactured by many different and versatile techniques. Their contribution in AD regards mainly the delivery of bioactive agents in a targeted and controlled manner through the blood-brain barrier and into the brain, with the ultimate goal to block the ß-amyloid (Aß) and/or tau aggregation. Their flexibility and biocompatibility as platforms, combined with their ability to protect the encapsulated/incorporated molecules, are advantages that are expected to assist this endeavor.

Chimeric Stimuli-Responsive Liposomes as Nanocarriers for the Delivery of the Anti-Glioma Agent TRAM-34.

Nanocarriers are delivery platforms of drugs, peptides, nucleic acids and other therapeutic molecules that are indicated for severe human diseases. Gliomas are the most frequent type of brain tumor, with glioblastoma being the most common and malignant type. The current state of glioma treatment requires innovative approaches that will lead to efficient and safe therapies. Advanced nanosystems and stimuli-responsive materials are available and well-studied technologies that may contribute to this effort. The present study deals with the development of functional chimeric nanocarriers composed of a phospholipid and a diblock copolymer, for the incorporation, delivery and pH-responsive release of the antiglioma agent TRAM-34 inside glioblastoma cells. Nanocarrier analysis included light scattering, protein incubation and electron microscopy, and fluorescence anisotropy and thermal analysis techniques were also applied. Biological assays were carried out in order to evaluate the nanocarrier nanotoxicity in vitro and in vivo, as well as to evaluate antiglioma activity. The nanosystems were able to successfully manifest functional properties under pH conditions, and their biocompatibility and cellular internalization were also evident. The chimeric nanoplatforms presented herein have shown promise for biomedical applications so far and should be further studied in terms of their ability to deliver TRAM-34 and other therapeutic molecules to glioblastoma cells.

Preparation and Biophysical Characterization of Quercetin Inclusion Complexes with ß-Cyclodextrin Derivatives to be Formulated as Possible Nose-to-Brain Quercetin Delivery Systems.

Quercetin (Que) is a flavonoid associated with high oxygen radical scavenging activity and potential neuroprotective activity against Alzheimer's disease. Que's oral bioavailability is limited by its low water solubility and extended peripheral metabolism; thus, nasal administration may be a promising alternative to achieve effective Que concentrations in the brain. The formation of Que-2-hydroxypropylated-ß-cyclodextrin (Que/HP-ß-CD) complexes was previously found to increase the molecule's solubility and stability in aqueous media. Que-methyl-ß-cyclodextrin (Que/Me-ß-CD) inclusion complexes were prepared, characterized, and compared with the Que/HP-ß-CD complex using biophysical and computational methods (phase solubility, fluorescence and NMR spectroscopy, differential scanning calorimetry (DSC), and molecular dynamics simulations (MDS)) as candidates for the preparation of nose-to-brain Que's delivery systems. DSC thermograms, NMR, fluorescence spectroscopy, and MDS confirmed the inclusion complex formation of Que with both CDs. Differences between the two preparations were observed regarding their thermodynamic stability and inclusion mode governing the details of molecular interactions. Que's solubility in aqueous media at pH 1.2 and 4.5 was similar and linearly increased with both CD concentrations. At pH 6.8, Que's solubility was higher and positively deviated from linearity in the presence of HP-ß-CD more than with Me-ß-CD, possibly revealing the presence of more than one HP-ß-CD molecule involved in the complex. Overall, water solubility of lyophilized Que/Me-ß-CD and Que/HP-ß-CD products was approximately 7-40 times and 14-50 times as high as for pure Que at pH 1.2-6.8. In addition, the proof of concept experiment on ex vivo permeation across rabbit nasal mucosa revealed measurable and similar Que permeability profiles with both CDs and negligible permeation of pure Que. These results are quite encouraging for further ex vivo and in vivo evaluation toward nasal administration and nose-to-brain delivery of Que.

Incorporation of PEGylated δ-decalactone into lipid bilayers: thermodynamic study and chimeric liposomes development.

Liposomes have been on the market as drug delivery systems for over 25 years. Their success comes from the ability to carry toxic drug molecules to the appropriate site of action through passive accumulation, thus reducing their severe side effects. However, the need for enhanced circulation time and site and time-specific drug delivery turned research focus on other systems, such as polymers. In this context, novel composites that combine the flexibility of polymeric nanosystems with the properties of liposomes gained a lot of interest. In the present work a mixed/chimeric liposomal system, composed of phospholipids and block copolymers, was developed and evaluated in regards with its feasibility as a drug delivery system. These innovative nano-platforms combine advantages from both classes of biomaterials. Thermal analysis was performed in order to offers an insight into the interactions between these materials and consequently into their physicochemical characteristics. In addition, colloidal stability was assessed by monitoring z-potential and size distribution over time. Finally, their suitability as carriers for biomedical applications was evaluated by carrying out in vitro toxicity studies.

Rindera graeca (Boraginaceae) Phytochemical Profile and Biological Activities.

Rindera graeca is a Greek endemic plant of the Boraginaceae family which has never been studied before. Consequently, this study attempted to phytochemically examine the aerial parts of this species. Nine phenolic secondary metabolites were identified, consisting of seven caffeic acid derivatives and two flavonol glucosides, namely rutin and quercetin-3-rutinoside-7-rhamnoside. These flavonoids, together with rosmarinic acid, were isolated via column chromatography and structurally determined through spectral analysis. Quercetin-3-rutinoside-7-rhamnoside is an unusual triglycoside, which is identified for the first time in Rindera genus and among Boraginaceae plants. This metabolite was further examined with thermal analysis and its 3D structure was simulated, revealing some intriguing information on its interaction with biological membrane models, which might have potential applications in microcirculation-related conditions. R. graeca was also analyzed for its pyrrolizidine alkaloids content, and it was found to contain echinatine together with echinatine N-oxide and rinderine N-oxide. Additionally, the total phenolic and flavonoid contents of R. graeca methanol extract were determined, along with free radical inhibition assays. High total phenolic content and almost complete inhibition at experimental doses at the free radical assays indicate a potent antioxidant profile for this plant. Overall, through phytochemical analysis and biological activity assays, insight was gained on an endemic Greek species of the little-studied Rindera genus, while its potential for further applications has been assessed.

Physicochemical study of the protein-liposome interactions: influence of liposome composition and concentration on protein binding.

The aim of the present study is to investigate the interactions between liposomes and proteins and to evaluate the role of liposomal lipid composition and concentration in the formation of protein corona. Liposomes composed of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) or hydrogenated soybean phosphatidylcholine (HSPC) with 1,2-dipalmitoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (sodium salt) (DPPG), 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)-3000] (DPPE-PEG 3000), cholesterol (CH) or mixtures of these lipids, were prepared at different concentrations by the thin-film hydration method. After liposomes were dispersed in HPLC-grade water and foetal bovine serum (FBS), their physicochemical characteristics, such as size, size distribution, and ζ-potential, were determined using dynamic and electrophoretic light scattering. Aggregation of DPPC, HSPC, DPPC:CH (9:1 molar ratio), and HSPC:CH (9:1 molar ratio) in FBS was observed. On the contrary, liposomes incorporating DPPG lipids and CH both in a molar ratio of 11% were found to be stable over time, while their size did not alter dramatically in biological medium. Liposomes containing CH and PEGylated lipids retain their size in the presence of serum as well as their physical stability. In addition, our results indicate that the protein binding depends on the presence of polyethylene glycol (PEG), CH, concentration and surface charge. In this paper, we introduce a new parameter, fraction of stealthiness (Fs), for investigating the extent of protein binding to liposomes. This parameter depends on the changes in size of liposomes after serum incubation, while liposomes have stealth properties when Fs is close to 1. Thus, we conclude that lipid composition and concentration affect the adsorption of proteins and the liposomal stabilization.

The significance of drug-to-lipid ratio to the development of optimized liposomal formulation.

Liposomes are considered to be one of the most extensively investigated drug delivery nanosystems. Each drug can be loaded either in the liposomal hydrophilic core or within the lipidic bilayer and delivered eventually to the proper site into the organism. There are already many marketed approved liposomal products. The development of a liposomal product is a quite complicated process, while many critical parameters have to be investigated during the preparation process. The present study deals with the drug-to-lipid ratio (D/L ratio), which is a critical process parameter, expresses the actual capacity of the liposome to accommodate the drug and can play a key role at the optimization of every liposomal formulation. D/L ratio is affected by the composition, the different biomaterials and the loading method being used, so the improvement of D/L ratio can optimize the liposomal formulation. D/L ratio can be used as an index of the effectiveness of the preparation method too. Furthermore, D/L ratio influences the therapeutic efficacy of the liposomal product, expressing the actual dose of the drug being administrated. There is a variety of analytical methods, quantifying the drug and the lipids and estimating eventually the D/L ratio. According to the regulatory framework of nanomedicine, about the development of nanosimilars, D/L ratio is a necessary element for the nanosimilar product description and the statement of product comparability.

Development and Evaluation of Stimuli-Responsive Chimeric Nanostructures.

Chimeric/mixed stimuli-responsive nanocarriers are promising agents for therapeutic and diagnostic applications, as well as in the combinatorial field of theranostics. Herein, we designed chimeric nanosystems, composed of natural phospholipid and pH-sensitive amphiphilic diblock copolymer, in different molar ratios and assessed the polymer lyotropic effect on their properties. Initially, polymer-grafted bilayers were evaluated for their thermotropic behavior by thermal analysis. Chimeric liposomes were prepared through thin-film hydration and the obtained vesicles were studied by light scattering techniques, to measure their physicochemical characteristics and colloidal stability, as well as by imaging techniques, to elucidate their global and membrane morphology. Finally, in vitro screening of the systems' toxicity was held. The copolymer effect on the membrane phase transition strongly depended on the pH of the surrounding environment. Chimeric nanoparticles were around and above 100 nm, while electron microscopy revealed occasional morphology diversity, probably affecting the toxicity of the systems. The latter was assessed to be tolerable, while dependent on the nanosystems' material concentration, polymer concentration, and polymer composition. All experiments suggested that the thermodynamic and biophysical properties of the nanosystems are copolymer-composition- and concentration-dependent, since different amounts of incorporated polymer would produce divergent effects on the lyotropic liquid crystal membrane. Certain chimeric systems can be exploited as advanced drug delivery nanosystems, based on their overall promising profiles.

Design and development of pH-responsive HSPC:C12H25-PAA chimeric liposomes.

The application of stimuli-responsive medical practices has emerged, in which pH-sensitive liposomes figure prominently. This study investigates the impact of the incorporation of different amounts of pH-sensitive polymer, C12H25-PAA (poly(acrylic acid) with a hydrophobic end group) in l-α-phosphatidylcholine, hydrogenated (Soy) (HSPC) phospholipidic bilayers, with respect to biomimicry and functionality. PAA is a poly(carboxylic acid) molecule, classified as a pH-sensitive polymer, whose pH-sensitivity is attributed to its regulative -COOH groups, which are protonated under acidic pH (pKa ∼4.2). Our concern was to fully characterize, in a biophysical and thermodynamical manner, the mixed nanoassemblies arising from the combination of the two biomaterials. At first, we quantified the physicochemical characteristics and physical stability of the prepared chimeric nanosystems. Then, we studied their thermotropic behavior, through measurement of thermodynamical parameters, using Differential Scanning Calorimetry (DSC). Finally, the loading and release of indomethacin (IND) were evaluated, as well as the physicochemical properties and stability of the nanocarriers incorporating it. As expected, thermodynamical findings are in line with physicochemical results and also explain the loading and release profiles of IND. The novelty of this investigation is the utilization of these pH-sensitive chimeric advanced Drug Delivery nano Systems (aDDnSs) in targeted drug delivery which relies entirely on the biophysics and thermodynamics between such designs and the physiological membranes and environment of living organisms.

Exosome-like genistein-loaded nanoparticles developed by thin-film hydration and 3D-printed Tesla microfluidic chip: A comparative study.

Exosomes are naturally derived information carriers that present interest as drug delivery systems. However, their vague cargo and isolation difficulties hinder their use in clinical practice. To overcome these limitations, we developed exosome-like nanoparticles, consisted of the main lipids of exosomes, using two distinct methods: thin-film hydration and 3D-printed microfluidics. Our novel microfluidic device, fabricated through digital light processing printing, demonstrated a favorable architecture to produce exosome-like nanoparticles. We compared these two techniques by analyzing the physicochemical characteristics (size, size distribution, and ζ-potential) of both unloaded and genistein-loaded exosome-like nanoparticles, using dynamic and electrophoretic light scattering. Our findings revealed that the presence of small lipophilic molecules, cholesterol and/or genistein, influenced the characteristics of the final formulations differently based on the development approach. Regardless of the initial differences of the formulations, all exosome-like nanoparticles, whether loaded with genistein or not, exhibited remarkable colloidal stability over time. Furthermore, an encapsulation efficiency of over 87% for genistein was achieved in all cases. Additionally, thermal analysis uncovered the presence of metastable phases within the membranes, which could impact the drug delivery efficiency. In summary, this study provides a comprehensive comparison between conventional and innovative methods for producing complex liposomal nanosystems, exemplified by exosome-like nanoparticles.

Biophysical interactions of mixed lipid-polymer nanoparticles incorporating curcumin: Potential as antibacterial agent.

The technology of lipid nanoparticles has a long history in drug delivery, which begins with the discovery of liposomes by Alec D Bangham in the 1960s. Since then, numerous studies have been conducted on these systems, and several nanomedicinal products that utilize them have entered the market, with the latest being the COVID-19 vaccines. Despite their success, many aspects of their biophysical behavior are still under investigation. At the same time, their combination with other classes of biomaterials to create more advanced platforms is a promising endeavor. Herein, we developed mixed lipid-polymer nanoparticles with incorporated curcumin as a drug delivery system for therapy, and we studied its interactions with various biosystems. Initially, the nanoparticle physicochemical properties were investigated, where their size, size distribution, surface charge, morphology, drug incorporation and stability were assessed. The incorporation of the drug molecule was approximately 99.8 % for a formulated amount of 10 % by weight of the total membrane components and stable in due time. The association of the nanoparticles with human serum albumin and the effect that this brings upon their properties was studied by several biophysical techniques, including light scattering, thermal analysis and circular dichroism. As a biocompatibility assessment, interactions with erythrocyte membranes and hemolysis induced by the nanoparticles were also studied, with empty nanoparticles being more toxic than drug-loaded ones at high concentrations. Finally, interactions with bacterial membrane proteins of Staphylococcus aureus and the antibacterial effect of the nanoparticles were evaluated, where the effect of curcumin was improved when incorporated inside the nanoparticles. Overall, the developed mixed nanoparticles are promising candidates for the delivery of curcumin to infectious and other types of diseases.

Interaction of Rhus typhina Tannin with Lipid Nanoparticles: Implication for the Formulation of a Tannin-Liposome Hybrid Biomaterial with Antibacterial Activity.

Tannins are natural plant origin polyphenols that are promising compounds for pharmacological applications due to their strong and different biological activities, including antibacterial activity. Our previous studies demonstrated that sumac tannin, i.e., 3,6-bis-O-di-O-galloyl-1,2,4-tri-O-galloyl-ß-D-glucose (isolated from Rhus typhina L.), possesses strong antibacterial activity against different bacterial strains. One of the crucial factors of the pharmacological activity of tannins is their ability to interact with biomembranes, which may result in the penetration of these compounds into cells or the realization of their activity on the surface. The aim of the current work was to study the interactions of sumac tannin with liposomes as a simple model of the cellular membrane, which is widely used in studies focused on the explanation of the physicochemical nature of molecule-membrane interactions. Additionally, these lipid nanovesicles are very often investigated as nanocarriers for different types of biologically active molecules, such as antibiotics. In the frame of our study, using differential scanning calorimetry, zeta-potential, and fluorescence analysis, we have shown that 3,6-bis-O-di-O-galloyl-1,2,4-tri-O-galloyl-ß-D-glucose interacts strongly with liposomes and can be encapsulated inside them. A formulated sumac-liposome hybrid nanocomplex demonstrated much stronger antibacterial activity in comparison with pure tannin. Overall, by using the high affinity of sumac tannin to liposomes, new, functional nanobiomaterials with strong antibacterial activity against Gram-positive strains, such as S. aureus, S. epidermitis, and B. cereus, can be formulated.

Lipid-coated ruthenium dendrimer conjugated with doxorubicin in anti-cancer drug delivery: Introducing protocols.

One of the major limitations for the treatment of many diseases is an inability of drugs to cross the cell membrane barrier. Different kinds of carriers are being investigated to improve drug bioavailability. Among them, lipid or polymer-based systems are of special interest due to their biocompatibility. In our study, we combined dendritic and liposomal carriers and analysed the biochemical and biophysical properties of these formulations. Two preparation methods of Liposomal Locked-in Dendrimers (LLDs) systems have been established and compared. Carbosilane ruthenium metallodendrimer was complexed with an anti-cancer drug (doxorubicin) and locked in a liposomal structure, using both techniques. The LLDs systems formed by hydrophilic locking had more efficient transfection profiles and interacted with the erythrocyte membrane better than systems using the hydrophobic method. The results indicate these systems have improved transfection properties when compared to non-complexed components. The coating of dendrimers with lipids significantly reduced their hemotoxicity and cytotoxicity. The nanometric size, low polydispersity index and reduced positive zeta potential of such complexes made them attractive for future application in drug delivery. The formulations prepared by the hydrophobic locking protocol were not effective and will not be considered furthermore as prospective drug delivery systems. In contrast, the formulations formed by the hydrophilic loading method have shown promising results where the cytotoxicity of LLD systems with doxorubicin was more effective against cancer than normal cells.

Synthesis and Testing of Analogs of the Tuberculosis Drug Candidate SQ109 against Bacteria and Protozoa: Identification of Lead Compounds against Mycobacterium abscessus and Malaria Parasites.

SQ109 is a tuberculosis drug candidate that has high potency against Mycobacterium tuberculosis and is thought to function at least in part by blocking cell wall biosynthesis by inhibiting the MmpL3 transporter. It also has activity against bacteria and protozoan parasites that lack MmpL3, where it can act as an uncoupler, targeting lipid membranes and Ca2+ homeostasis. Here, we synthesized 18 analogs of SQ109 and tested them against M. smegmatis, M. tuberculosis, M. abscessus, Bacillus subtilis, and Escherichia coli, as well as against the protozoan parasites Trypanosoma brucei, T. cruzi, Leishmania donovani, L. mexicana, and Plasmodium falciparum. Activity against the mycobacteria was generally less than with SQ109 and was reduced by increasing the size of the alkyl adduct, but two analogs were ∼4-8-fold more active than SQ109 against M. abscessus, including a highly drug-resistant strain harboring an A309P mutation in MmpL3. There was also better activity than found with SQ109 with other bacteria and protozoa. Of particular interest, we found that the adamantyl C-2 ethyl, butyl, phenyl, and benzyl analogs had 4-10× increased activity against P. falciparum asexual blood stages, together with low toxicity to a human HepG2 cell line, making them of interest as new antimalarial drug leads. We also used surface plasmon resonance to investigate the binding of inhibitors to MmpL3 and differential scanning calorimetry to investigate binding to lipid membranes. There was no correlation between MmpL3 binding and M. tuberculosis or M. smegmatis cell activity, suggesting that MmpL3 is not a major target in mycobacteria. However, some of the more active species decreased lipid phase transition temperatures, indicating increased accumulation in membranes, which is expected to lead to enhanced uncoupler activity.

Innovative vaccine platforms against infectious diseases: Under the scope of the COVID-19 pandemic.

While classic vaccines have proved greatly efficacious in eliminating serious infectious diseases, innovative vaccine platforms open a new pathway to overcome dangerous pandemics via the development of safe and effective formulations. Such platforms play a key role either as antigen delivery systems or as immune-stimulators that induce both innate and adaptive immune responses. Liposomes or lipid nanoparticles, virus-like particles, nanoemulsions, polymeric or inorganic nanoparticles, as well as viral vectors, all belong to the nanoscale and are the main categories of innovative vaccines that are currently on the market or in clinical and preclinical phases. In this paper, we review the above formulations used in vaccinology and we discuss their connection with the development of safe and effective prophylactic vaccines against SARS-CoV-2.

A Differential Scanning Calorimetry (DSC) Experimental Protocol for Evaluating the Modified Thermotropic Behavior of Liposomes with Incorporated Guest Molecules.

Differential scanning calorimetry (DSC) is a well-established technique, suitable to monitor the interactions that may take place among the drug delivery systems of liposomes and the potential bioactive molecules that are incorporated inside them. Moreover, the DSC technique is considered to be a useful tool to characterize the thermal behavior of lipidic bilayers in the absence and presence of drugs and to highlight parameters, such as the cooperativity between the lipids and the guest molecules (i.e. drugs, polymers, dendrimers), providing also a prediction of the behavior of potential future drug delivery liposomal platforms. In this study, a protocol for DSC measurements on liposomal systems with incorporated guest molecules is described.

Differential Scanning Calorimetry (DSC) on Sartan/Cyclodextrin Delivery Formulations.

Differential scanning calorimetry (DSC) is a widely utilized method for the interactions of drug molecules with drug delivery systems (DDSs). Herein is described a protocol for studying the interactions and entrapment efficiency of the prototype sartan losartan and the polydynamic, structurally similar irbesartan inside the nontoxic 2-hydroxypropyl-ß-cyclodextrin (2-HP-ß-CD). The thermal scan properties of both sartan molecules have been studied when physically mixed or complexed with the cyclodextrin. The thermograms indeed showed significant differences between the mixtures and complexes, establishing DSC as a valuable method to characterize the state of the drugs in these pharmaceutical formulations.