The development of thymol-isatin hybrids as broad-spectrum antibacterial agents with potent anti-MRSA activity.

Bacterial resistance toward available therapeutic agents has become a nightmare for the healthcare system, causing significant mortality as well as prolonged hospitalization, thereby needing the urgent attention of research groups working on antimicrobial drug development worldwide. Molecular hybridization is a well-established tool for developing multifunctional compounds to tackle drug resistance. Inspired by the antibacterial profiles of isatin and thymol, along with the efficiency of a triazole linker in molecular hybridization, herein, we report the design, synthesis and antibacterial activity of a novel series of triazole tethered thymol-isatin hybrids. Most of the hybrids exhibited a broad-spectrum antibacterial efficacy against standard human pathogenic as well as clinically isolated multidrug-resistant bacterial strains listed in the WHO's 'priority pathogen' list and also in the ESKAPE group. Among them, hybrid compound AS8 was the most effective against methicillin-resistant Staphylococcus aureus (MIC = 1.9 µM and MBC = 3.9 µM), exhibiting biofilm inhibitory potential. AS8 exhibited dehydrosqualene synthase (CrtM) inhibitory potential in MRSA and decreased the production of virulence factor staphyloxanthin, which is one of the key mechanisms of its anti-MRSA efficacy, which was further supported by molecular docking and simulation studies. Moreover, AS8 was found to be non-toxic and showed a potent in vivo antibacterial efficacy (90% survival at 10 mg kg-1) as well as a modulated immune response in the larva-based (Galleria mellonella) model of systemic infections. Overall findings confirmed that AS8 can be a promising candidate or take the lead in the treatment and further drug development against drug-resistant infectious diseases, especially against MRSA infections.

Past, present and future of xanthine oxidase inhibitors: design strategies, structural and pharmacological insights, patents and clinical trials.

Xanthine oxidase, a molybdo-flavoenzyme, and an isoform of xanthine dehydrogenase both exist as xanthine oxidoreductase and are responsible for purine catabolism. Xanthine oxidase is more involved in pathological conditions when extensively modulated. Elevation of xanthine oxidase is not only the prime cause of gout but is also responsible for various hyperuricemia associated pathological conditions like diabetes, chronic wounds, cardiovascular disorders, Alzheimer's disease, etc. Currently available xanthine oxidase inhibitors in clinical practice (allopurinol, febuxostat and topiroxostat) suffer from fatal side effects that pose a serious problem to the healthcare system, raising global emergency to develop novel, potent and safer xanthine oxidase inhibitors. This review will provide key and systematic information about: a. design strategies (inspired from both marketed drugs in clinical practice and natural products), structural insights and pharmacological output (xanthine oxidase inhibition and associated activities) of various pre-clinical candidates reported by various research groups across the globe in the past two decades; b. patented xanthine oxidase inhibitors published in the last three decades and c. clinical trials and their outcomes on approved drug candidates. Information generated in this review has suggested fragment-based drug design (FBDD) and molecular hybridization techniques to be most suitable for development of desired xanthine oxidase inhibitors as one provides high selectivity toward the enzyme and the other imparts multifunctional properties to the structure and both may possess capabilities to surpass the limitations of currently available clinical drugs. All in combination will exclusively update researchers working on xanthine oxidase inhibitors and allied areas and potentially help in designing rational, novel, potent and safer xanthine oxidase inhibitors that can effectively tackle xanthine oxidase related disease conditions and disorders.

Pathogenesis of Alzheimer's Disease and Diversity of 1,2,3-Triazole Scaffold in Drug Development: Design Strategies, Structural Insights, and Therapeutic Potential.

Alzheimer's disease is a most prevalent form of dementia all around the globe and currently poses a significant challenge to the healthcare system. Currently available drugs only slow the progression of this disease rather than provide proper containment. Identification of multiple targets responsible for this disease in the last three decades established it as a multifactorial neurodegenerative disorder that needs novel multifunctional agents for its management and the possible reason for the failure of currently available single target clinical drugs. 1,2,3-Triazole is a miraculous nucleus in medicinal chemistry and the first choice for development of multifunctional hybrid molecules. Apart from that, it is an integral component of various drugs in clinical trials as well as in clinical practice. This review is focused on the pathogenesis of Alzheimer's disease and 1,2,3-triazole containing derivatives developed in recent decades as potential anti-Alzheimer's agents. The review will provide (A) precise insight of various established targets of Alzheimer's disease including cholinergic, amyloid, tau, monoamine oxidases, glutamate, calcium, and reactive oxygen species hypothesis and (B) design hypothesis, structure-activity relationships, and pharmacological outcomes of 1,2,3-triazole containing multifunctional anti-Alzheimer's agents. This review will provide a baseline for various research groups working on Alzheimer's drug development in designing potent, safer, and effective multifunctional anti-Alzheimer's candidates of the future.

Mechanistic insight and structure activity relationship of isatin-based derivatives in development of anti-breast cancer agents.

Breast cancer is most common in women and most difficult to manage that causes highest mortality and morbidity among all diseases and posing significant threat to mankind as well as burden on healthcare system. In 2020, 2.3 million women were diagnosed with breast cancer and it was responsible for 685,000 deaths globally, suggesting the severity of this disease. Apart from that, relapsing of cases and resistance among available anticancer drugs along with associated side effects making the situation even worse. Therefore, it is a global emergency to develop potent and safer antibreast cancer agents. Isatin is most versatile and flying one nucleus which is an integral competent and various anticancer agent in clinical practice and widely used by various research groups around the globe for development of novel, potent, and safer antibreast cancer agents. This review will shed light on the structural insights and antiproliferative potential of various isatin-based derivatives developed for targeting breast cancer in last three decades that will help researchers in design and development of novel, potent, and safer isatin-based antibreast cancer agents.

Recent advances in antifungal drug development targeting lanosterol 14α-demethylase (CYP51): A comprehensive review with structural and molecular insights.

Fungal infections are posing serious threat to healthcare system due to emerging resistance among available antifungal agents. Among available antifungal agents in clinical practice, azoles (diazole, 1,2,4-triazole and tetrazole) remained most effective and widely prescribed antifungal agents. Now their associated side effects and emerging resistance pattern raised a need of new and potent antifungal agents. Lanosterol 14α-demethylase (CYP51) is responsible for the oxidative removal of 14α-methyl group of sterol precursors lanosterol and 24(28)-methylene-24,25-dihydrolanosterol in ergosterol biosynthesis hence an essential component of fungal life cycle and prominent target for antifungal drug development. This review will shed light on various azole- as well as non-azoles-based derivatives as potential antifungal agents that target fungal CYP51. Review will provide deep insight about structure activity relationship, pharmacological outcomes, and interactions of derivatives with CYP51 at molecular level. It will help medicinal chemists working on antifungal development in designing more rational, potent, and safer antifungal agents by targeting fungal CYP51 for tackling emerging antifungal drug resistance.

1,2,3-Triazole Derivatives as an Emerging Scaffold for Antifungal Drug Development against Candida albicans: A Comprehensive Review.

Candida infections are most prominent among fungal infections majorly target immunocompromised and hospitalized patients and cause significant morbidity and mortality. Candida albicans is the notorious and most prevalent among all pathogenic Candida strains. Its emerging resistance toward available antifungal agents making it hard to tackle and emerging as global healthcare emergency. Simultaneously, 1,2,3-triazole nucleus is a privileged scaffold that is gaining importance in antifungal drug development due to being a prominent bioactive linker and isostere of triazole based antifungal class core 1,2,4-triazole. Numerous reports have been updated in scientific literature in last few decades related to utilization of 1,2,3-triazole nucleus in antifungal drug development against Candida albicans. Present review will shed light on various preclinical studies focused on development of 1,2,3-triazole derivatives targeting Candida albicans along with brief highlight on clinical trials and newly approved drugs. Structure-activity relationship has been precisely discussed for each architect along with future perspective that will help medicinal chemists in design and development of potent antifungal agents for tackling infections derived from Candida albicans.

Mitigating Drug Stability Challenges Through Cocrystallization.

Drug stability plays a significant role in the pharmaceutical industry from early-phase drug discovery to product registration as well as the entire life cycle of a product. Various formulation approaches have been employed to overcome drug stability issues. These approaches are sometimes time-consuming which ultimately affect the timeline of the product launch and may further require formulation optimization steps, affecting the overall cost. Pharmaceutical cocrystal is a well-established route to fine tune the biopharmaceutical properties of drugs without covalent modification. This article highlights the role of cocrystallization in mitigating the stability issues of challenging drug molecules. Representative case studies wherein the drug stability issue is addressed through pharmaceutical cocrystals have been discussed briefly and are summarized in tabular form. The emphasis has been made on the structural information of cocrystals and understanding the mechanism that improves the stability of the parent drug through cocrystallization. Besides, a guided strategy has been proposed to modulate the stability of drug molecules through cocrystallization approach. Finally, the stability concern of fixed-dose or drug combinations and the challenges associated with cocrystals are also touched.

Pharmaceutical Cocrystals of Famotidine: Structural and Biopharmaceutical Evaluation.

Famotidine (FMT) an anti-ulcer drug, recently being repurposed in COVID-19 treatment, suffers from poor aqueous solubility and restricted bioavailability (<40%). To conquer the limitations endured by this potent anti-ulcer agent, two novel 1:1 cocrystals of FMT, namely Famotidine-Sorbic Acid (FSOR) and Famotidine-Syringic Acid (FSY), were synthesized using the liquid-assisted grinding method and evaluated. Distinct DSC thermograms and PXRD patterns advocate the existence of a new crystalline form. The unique organization of the hydrogen-bonded network, in the prepared cocrystals, is inferred by variation in characteristic vibrational frequencies in FT-IR spectroscopic analysis and supported by crystal structure determination. FSOR cocrystallize in orthorhombic PNCB and FSY in triclinic P 1 crystal system. Further, a significant amplification in the solubility (9 to 5-fold) and dissolution (8 to 5-fold) of FMT in cocrystalline form, with simultaneous augmentation in peak plasma concentration (2 to 1.5-fold higher) and relative bioavailability (approx. 200% to 135%). This is associated with the remarkable increment in their anti-ulcer and anti-oxidant potential. Thus, the study illustrates that cocrystallization as a worthy approach in the efficient delivery of neutral compounds suffering from inadequate solubility crisis.

Design, synthesis, and biological evaluation of isatin-indole-3-carboxaldehyde hybrids as a new class of xanthine oxidase inhibitors.

A novel series of triazole-linked isatin-indole-3-carboxaldehyde hybrids based on the febuxostat skeleton and its binding site interactions were rationally designed and synthesized as potential xanthine oxidase inhibitors. Among the synthesized hybrids, A19 showed the most potent xanthine oxidase inhibition (IC50 = 0.37 µM) with the mixed-type inhibitory scenario. Structure-activity relationship studies revealed that methoxy (OCH3 ) substitution on position 5 of the isatin nucleus and a two-carbon distance between isatin and the triazole moiety is most tolerable for the inhibitory potential. Various binding interactions of A19 with the binding site of xanthine oxidase are also streamlined by molecular docking studies, which showcase the favorable binding pattern for xanthine oxidase inhibition by the hybrid. Furthermore, molecular dynamic studies were performed that suggest the stability of the enzyme-hybrid complex. Overall, the study suggests that hybrid A19 can act as an effective hit lead for further development of potent xanthine oxidase inhibitors.

Engineering a Remedy to Modulate and Optimize Biopharmaceutical Properties of Rebamipide by Synthesizing New Cocrystal: In Silico and Experimental Studies.

PURPOSE: Rebamipide (REB) a potent anti-ulcer agent, has not been exploited to its full potential, owing to it extremely poor solubility, leading to highly diminutive bioavailability (<10%). The purpose is to carry out its solid-state modification. METHOD: Cocrystallisation was done with three GRAS coformers namely citric acid (CA), 3,4-dihydroxybenzoic acid (DHBA) and oxalic acid (OXA) employing the liquid-assisted grinding method. Cocrystal formation was based upon amide-carboxyl and amide-hydroxyl supramolecular synthons. Characterization of novel cocrystals i.e. RCA, RDHBA and ROXA was carried out by DSC, PXRD and additionally by FT-IR spectroscopy. Chemical structures have been determined utilizing the PXRD pattern by Material Studio®. Furthermore, cocrystals were subjected to solubility and intrinsic dissolution rate (IDR) evaluation. Also, pharmacodynamic and pharmacokinetic studies were performed and compared with pure rebamipide. RESULT: The appearances of a single sharp melting endotherm in DSC, along with novel characteristic peaks in PXRD infer the existence of a new crystalline form. Shifting in characteristic vibrations in FT-IR spectroscopy supports the establishment of distinct hydrogen-bonded networks. Structural determination revealed that RCA crystallizes in 'Bb2b' space groups whereas RDHBA in 'P1' and ROXA crystallize out in the 'P-1' space group. All the cocrystals exhibited superior apparent solubility and almost 7-13 folds increase in IDR. Furthermore, 1.6-2.5 folds enhancement in relative bioavailability and remarkable amplification in anti-ulcer, anti-inflammatory and the antioxidant potential of these cocrystals were observed. CONCLUSION: The study ascertains the advantages of cocrystallization, with RCA showing greatest potential and suggests a viable alternative approach for improved formulation of rebamipide.

Emerging Multi-Drug Eutectics: Opportunities and Challenges.

Complexity and heterogeneous nature of most diseases have posed greater challenges in the modern healthcare system. Fixed-dose combination can offer an ideal way to improve patient compliance and higher therapeutic efficacy. However, biopharmaceutical issues associated with the drug combinations remain unaddressed. Multidrug eutectics (MDE) have demonstrated significant promise in improving the biopharmaceutical attributes with synergistic therapeutic action. Eutectic mixtures are the multicomponent solid forms that possess lesser melting point than the individual components at a fixed composition. Non-covalent linking of drug combinations as MDE is an innovative strategy with enhanced solubility, dissolution, and mechanical and potential therapeutic efficacy. This review provides a comprehensive overview of the design of MDE, rational selection of drugs, characterization tools, and their therapeutic potential. Besides, the futuristic perspective where MDE could make a significant impact on combination therapy is briefly outlined. Graphical Abstract.

Cocrystals of diacerein: Towards the development of improved biopharmaceutical parameters.

The effectiveness of Diacerein as an anti-osteoarthritis drug is limited due to its acutely poor aqueous solubility and bioavailability. The present study demonstrates cocrystallization as a successful technique to improve the biopharmaceutical parameters of diacerein. Three cocrystals of diacerein were prepared by an eco-friendly technique with three suitable coformers namely isonicotinamide, nicotinamide, and theophylline. The formation of a new solid phase was inferred from the DSC thermograms and powder diffraction pattern and was supported by FTIR. The crystal structures of the cocrystals determined from the PXRD pattern using Material Studio software. Detailed analysis showed the formation of supramolecular hetero-synthons of complementary functional groups of the coformers with the carbonyl and carboxyl groups of diacerein. The structural conformation of the cocrystalline state was also provided by the shifts in the ssNMR pattern of the cocrystals. The three new cocrystals were found to have a relatively high solubility and intrinsic dissolution rate which showed remarkable improvement in anti-arthritic activity as compared to diacerein. Thus, proving cocrystallization to be a potential solution to the solubility limited bioavailability problems of diacerein.

Implication of Coformer Structural Diversity on Cocrystallization Outcomes of Telmisartan with Improved Biopharmaceutical Performance.

Crystal engineering approach was utilized for the development of different multicomponent solid forms of telmisartan (TEL) to improve its oral bioavailability. In this context, two cocrystals, gentisic acid (GA) and maleic acid (MA), while two eutectic mixtures, para-aminobenzoic acid (PABA) and adipic acid (AA), were successfully prepared and characterized by different analytical tools. Both the cocrystals exhibited characteristic heterosynthons, viz. OHacid⋯Narom and OHacid⋯O, to propagate new network. Structural features of coformers has been correlated with the outcomes of cocrystallization approach. Coformers having auxiliary functionality in addition to complementary functional groups have high propensity to generate cocrystals. However, multicomponent where auxiliary functionality is lacking, such combinations, is shown to form eutectic mixtures owing to strong homomeric interaction. Besides, the developed cocrystals and eutectic mixtures showed higher aqueous solubility (3-5.5-fold) and intrinsic dissolution rate (1-2.6-fold) over pure TEL. In vivo studies also revealed significant improvement in relative bioavailability (2-2.6-fold). The study also shed light on the implications of eutectic mixtures in mitigating the solubility issues of drugs which are often considered negative results of cocrystallization strategy.

Daidzein cocrystals: An opportunity to improve its biopharmaceutical parameters.

The present study involves the contribution of cocrystallization towards the modification of the biopharmaceutical parameters of poorly watersoluble plant-originated isoflavone, daidzein (DAID). The cocrystals were prepared with GRAS status coformers i.e., isonicotinamide, theobromine and cytosine using mechanochemical grinding and characterized by various analytical techniques (DSC, FT-IR, PXRD and solid-state NMR). Crystal structures were obtained from PXRD data using BIOVIA Materials Studio software and compared in terms of supramolecular motifs. An additional qualitative and quantitative insight into interactions between both components of the cocrystal illustrated the presence of OH⋯N and OH⋯O=C heterosynthons and revealed a stabilizing role of hydrogen bonding. The cocrystals were further evaluated for their solubility, intrinsic dissolution and in vivo profile. Solubility and dissolution studies of pure daidzein and its cocrystals, namely daidzein-isonicotinamide (DIS), daidzein-cytosine (DCYT) and daidzein-theobromine (DTB) exhibited an almost 2-fold improvement. Evaluation of maximum concentration (Cmax) of cocrystals reveals that the DIS cocrystal shows the highest Cmax of 1848.7 ng/ml followed by DCYT cocrystal (1614.9 ng/ml) and DTB cocrystal (1326.0 ng/ml) in comparison to DAID which has a Cmax 870.5 ng/ml. Each of these cocrystals showed significant enhancement in in vivo and in vitro activities in comparison to daidzein. Thus, this report suggests cocrystallization as a viable approach to resolve the solubility and bioavailability issues that circumvent the use of a therapeutically potential isoflavone, daidzein.

Implication of Differential Surface Anisotropy on Biopharmaceutical Performance of Polymorphic Forms of Ambrisentan.

The aim of the present study was to compare the dissolution rate and in vivo biopharmaceutical performance of 2 polymorphic forms (form I and II) of ambrisentan and correlate with their surface molecular environment. Dominance of various functionalities on the surface of specific crystal facets of both forms was predicted by Bravais-Friedel-Donnay-Harker method. Hirshfeld surface analysis maps and 2D fingerprint plots indicate a difference in shape index, curvedness, and relative percentage contribution of various contacts in both forms. Pre- and post-intrinsic dissolution compact studied by atomic force microscopy showed a significant difference in surface roughness and defects formation in form II as compared to form I which is attributed to the presence of more hydrophilic surfaces. The hydrophilic molecular surface environment of form II is ascribed to its improved intrinsic dissolution rate than form I. Furthermore, in vivo pharmacokinetic study also showed significantly higher AUC0-24 and Cmax in form II compared to form I. Overall, this study demonstrates that form I and II of ambrisentan exhibited the differential surface anisotropy which has significant implications on their biopharmaceutical performance.

Cocrystal of 5-Fluorouracil: Characterization and Evaluation of Biopharmaceutical Parameters.

To prepare the cocrystals of 5-fluorouracil (5-FU) with GRAS status coformers via a cocrystallization technique with an aim to improve physicochemical properties as well as bioavailability for colon cancer, breast cancer, and prostate cancer. The mechanochemical method was used in the preparations of three crystals of 5-FU with gentisic acid (5-FUGA), 3,4-dihydroxybenzoic acid (5-FUBA), and 4-aminopyridine (5-FUPN). A thermoanalytical and spectroscopic technique was used for their characterization. Their biological evaluation was done in different cancer cell lines. The new solid pure crystal forms were characterized by DSC, FTIR, and PXRD. The crystal structure was determined from single crystal and PXRD that exposed the existence of the monoclinic and triclinic crystal system with P21/n and P-1 space groups. The dermatokinetic studies on the rat skin revealed two- to threefold improvement in relative bioavailability as compared to pure 5-FU. "MTT assay was performed by varying the concentrations of the drug from 1 to 50 µg mL-1. After 24 h, the cell viability dropped to 70.67%, 74.05%, and 76.37% in MCF-7, Hela, and Caco-2 cell lines when the concentration of 5-FU was 50 µg mL-1", while it dropped dramatically in cocrystals 5-FUGA (22.06%, 24.63%, and 25.61%), 5-FUBA (31.22%, 29.46%, and 32.81%), and 5-FUPN (21.65%, 32.64%, and 21.46%). All the results indicated that 5-FU cocrystals possess better antitumor efficacy than free drug. Thus, cocrystallization expands the extent of the existing pre-formulation options ahead of pure API form to ameliorate the bioavailability and permeability.

Novel polymorph of ambrisentan: Characterization and stability.

The present work highlights a novel polymorph (form II) of ambrisentan (AMT), a selective endothelin type A (ETA) receptor antagonist used in the treatment of pulmonary arterial hypertension (PAH). Form II was isolated by solution crystallization and characterised by differential scanning calorimetry, powder X-ray diffraction, solution calorimetry and aqueous solubility. The single crystal X-ray diffraction shows that it crystallizes in monoclinic system with space group P21/c different from the form I (commercial form). Form II was found to be enantiotropically related to form I. Apparent solubility of form II was performed in 0.1 N HCl (pH 1.2) was found to be higher (1.5 fold) than of form I. Solution mediated and stress-induced phase transformation studies revealed conversion of form II to form I. Accelerated stability studies (40 °C & 75% RH) also reveal that form II converted to form I after one month. However, this does not belittle the improved solubility of a new solid form.

Antioxidant-Based Eutectics of Irbesartan: Viable Multicomponent Forms for the Management of Hypertension.

The present research work highlights the development of multicomponent solid form of the antihypertensive drug irbesartan (IRB) to improve its biopharmaceutical attributes. Mechanochemical synthesis of a new solid form of IRB with coformers having antioxidant properties (syringic acid, nicotinic acid, and ascorbic acid) resulted into three eutectic mixtures (EMs). Formation of eutectic was ascertained by differential scanning calorimetry whereas exact stoichiometry (50/50% w/w) was established by phase diagram and Tamman's triangle. The strong homomeric interaction between individual components and steric hindrances is responsible for the eutectic formation. EMs exhibited superior apparent solubility (five- to nine fold) and significant enhancement in intrinsic dissolution rate (two- to three fold) as compared to the plain drug. In vivo pharmacokinetic and in vivo pharmacodynamic studies revealed a significant improvement in the biopharmaceutical performance of EMs. Marked protection against oxidative stress was observed in EMs over plain drug by controlling the level/activity of plasma H2O2 and antioxidant enzymes (superoxide dismutase and catalase) in the kidney matrix of dexamethasone (Dexa)-induced hypertensive rats. Thus, these solid forms of IRB can serve as viable multicomponent forms to be translated into product development for better therapeutic efficacy in the management of hypertension.

A new polymorph of ciprofloxacin saccharinate: Structural characterization and pharmaceutical profile.

In this study, a new polymorph of ciprofloxacin saccharinate has been thoroughly evaluated with respect to structural as well as biopharmaceutical properties. Preliminary characterization of the new polymorph was performed by differential scanning calorimetry and thermogravimetric analysis, later confirmed by Fourier transform infra-red spectroscopy. The crystal structure was determined from the powder X-ray diffraction pattern using the direct-space algorithm. It lies in the triclinic P-1 space group. It is having lattice parameters different from previously reported forms. The solid-state 13C NMR data calculated from the crystal structure by exploiting density functional theory were found to be in excellent agreement with corresponding experimental 13C NMR data, thus providing a robust validation of the authenticity of the structure. The prepared polymorph shows enhanced aqueous solubility and dissolution rate in contrast to previously reported polymorph. The new form demonstrated improved oral bioavailability and inhibition of bacterial species. The enhanced biopharmaceutical properties are attributed to the higher extent of its absorption and distribution with respect to the individual components. The new form is a potential candidate for the pharmaceutical industry.

Is Failure of Cocrystallization Actually a Failure? Eutectic Formation in Cocrystal Screening of Hesperetin.

Cocrystal screening of hesperetin with certain countermolecules generated highly soluble noncovalent derivatives in the form of eutectics, instead of expected cocrystals. As adhesive forces established by complimentary functional groups on hesperetin and coformers were unable to overcome the stress due to size shape mismatch of component molecules, thus, eutectics were formed. Hesperetin, a polyphenolic antioxidant with potent anticancer and cardioprotective effects, has an underdeveloped role in modern therapeutics on account of its critically low aqueous solubility resulting in stunted bioavailability. The liquid-assisted cogrinding of hesperetin and coformers generated binary-phase eutectics in fixed stoichiometry with theophylline (1:1.5), adenine (2:1), gallic acid (1.5:1), and theobromine (2:1). Primarily characterized by lower melting endotherm in differential scanning calorimetry, the eutectics showed complete melting in hot-stage microscopy. Apart from characteristic V-shaped binary-phase diagram, no discernible changes in the FTIR and powder X-ray diffraction spectra further confirm eutectic formation. The morphological differences were analyzed by SEM measurements. A 2 to 4 times enhanced dissolution profile of the eutectics measured in pH 7.4 aqueous buffer was coupled with the in vitro (1,1-diphenyl-2-picryl hydroxyl free radical antioxidant assay and RBC antihemolytic assay) studies to present a complete preliminary data on the improved bioavailability of hesperetin eutectics.