Gemcitabine anticancer activity enhancement by water soluble celecoxib/sulfobutyl ether-β-cyclodextrin inclusion complex

Rutin/Sulfobutylether-β-Cyclodextrin as a Promising Therapeutic Formulation for Ocular Infection

Ocular pathologies present significant challenges to achieving effective therapeutic results due to various anatomical and physiological barriers. Natural products such as flavonoids, alone or in association with allopathic drugs, present many therapeutic actions including anticancer, anti-inflammatory, and antibacterial action. However, their clinical employment is challenging for scientists due to their low water solubility. In this study, we designed a liquid formulation based on rutin/sulfobutylether-β-cyclodextrin (RTN/SBE-β-CD) inclusion complex for treating ocular infections. The correct stoichiometry and the accurate binding constant were determined by employing SupraFit software (2.5.120) in the UV-vis titration experiment. A deep physical-chemical characterization of the RTN/SBE-β-CD inclusion complex was also performed; it confirmed the predominant formation of a stable complex (Kc, 9660 M-1) in a 1:1 molar ratio, with high water solubility that was 20 times (2.5 mg/mL) higher than the free molecule (0.125 mg/mL), permitting the dissolution of the solid complex within 30 min. NMR studies revealed the involvement of the bicyclic flavonoid moiety in the complexation, which was also confirmed by molecular modeling studies. In vitro, the antibacterial and antibiofilm activity of the formulation was assayed against Staphylococcus aureus and Pseudomonas aeruginosa strains. The results demonstrated a significant activity of the formulation than that of the free molecules.

Cyclodextrin Inclusion Complexes for Improved Drug Bioavailability and Activity: Synthetic and Analytical Aspects

Many active pharmaceutical ingredients show low oral bioavailability due to factors such as poor solubility and physical and chemical instability. The formation of inclusion complexes with cyclodextrins, as well as cyclodextrin-based polymers, nanosponges, and nanofibers, is a valuable tool to improve the oral bioavailability of many drugs. The microencapsulation process modifies key properties of the included drugs including volatility, dissolution rate, bioavailability, and bioactivity. In this context, we present relevant examples of the stabilization of labile drugs through the encapsulation in cyclodextrins. The formation of inclusion complexes with drugs belonging to class IV in the biopharmaceutical classification system as an effective solution to increase their bioavailability is also discussed. The stabilization and improvement in nutraceuticals used as food supplements, which often have low intestinal absorption due to their poor solubility, is also considered. Cyclodextrin-based nanofibers, which are polymer-free and can be generated using environmentally friendly technologies, lead to dramatic bioavailability enhancements. The synthesis of chemically modified cyclodextrins, polymers, and nanosponges based on cyclodextrins is discussed. Analytical techniques that allow the characterization and verification of the formation of true inclusion complexes are also considered, taking into account the differences in the procedures for the formation of inclusion complexes in solution and in the solid state.

Characterization and In Vivo Antiangiogenic Activity Evaluation of Morin-Based Cyclodextrin Inclusion Complexes

Morin (MRN) is a natural compound with antiangiogenic, antioxidant, anti-inflammatory, and anticancer activity. However, it shows a very low water solubility (28 μg/mL) that reduces its oral absorption, making bioavailability low and unpredictable. To improve MRN solubility and positively affect its biological activity, particularly its antiangiogenic activity, in this work, we prepared the inclusion complexes of MNR with sulfobutylether-β-cyclodextrin (SBE-β-CD) and hydroxypropyl-β-cyclodextrin (HP-β-CD). The inclusion complexes obtained by the freeze-drying method were extensively characterized in solution (phase-solubility studies, UV-Vis titration, and NMR spectroscopy) and in the solid state (TGA, DSC, and WAXD analysis). The complexation significantly increased the water solubility by about 100 times for MRN/HP-β-CD and 115 times for MRN/SBE-β-CD. Furthermore, quantitative dissolution of the complexes was observed within 60 min, whilst 1% of the free drug dissolved in the same experimental time. 1H NMR and UV-Vis titration studies demonstrated both CDs well include the benzoyl moiety of the drug. Additionally, SBE-β-CD could interact with the cinnamoyl moiety of MRN too. The complexes are stable in solution, showing a high value of association constant, that is, 3380 M-1 for MRN/HP-β-CD and 2870 M-1 for MRN/SBE-β-CD. In vivo biological studies on chick embryo chorioallantoic membrane (CAM) and zebrafish embryo models demonstrated the high biocompatibility of the inclusion complexes and the effective increase in antiangiogenic activity of complexed MRN with respect to the free drug.

Controlled Delivery of Celecoxib-β-Cyclodextrin Complexes from the Nanostructured Titanium Dioxide Layers

Considering the potential of nanostructured titanium dioxide layers as drug delivery systems, it is advisable to indicate the possibility of creating a functional drug delivery system based on anodic TiO₂ for celecoxib as an alternative anti-inflammatory drug and its inclusion complex with β-cyclodextrin. First, the optimal composition of celecoxib-β-cyclodextrin complexes was synthesized and determined. The effectiveness of the complexation was quantified using isothermal titration calorimetry (ITC), differential scanning calorimetry (DSC), infrared spectroscopy (FT-IR) nuclear magnetic resonance (¹H NMR), and scanning electron microscopy (SEM). Then, nanostructured titanium dioxide layers (TiO₂) were synthesized using the electrochemical oxidation technique. The TiO₂ layers with pore diameters of 60 nm and layer thickness of 1.60 µm were used as drug delivery systems. The samples were modified with pure celecoxib and the β-cyclodextrin-celecoxib complex. The release profiles shown effective drug release from such layers during 24 h. After the initial burst release, the drug was continuously released from the pores. The presented results confirm that the use of nanostructured TiO₂ as a drug delivery system can be effectively used in more complicated systems composed of β-cyclodextrin-celecoxib complexes, making such drugs available for pain treatment, e.g., for orthopedic surgeries.

A comparative study on inclusion complex formation between formononetin and β-cyclodextrin derivatives through multiscale classical and umbrella sampling simulations

Formononetin, a naturally occurring isoflavone exhibits a wide range of therapeutic applications including antioxidant, anti-tumor, antiviral, anti-diabetic and neuroprotective activities. However, the low hydro-solubility of formononetin has limited its prospective use in cosmetic, neutraceutical and pharmaceutical industries. Cyclodextrins (CDs), especially β-CD and its derivatives have emerged as promising agents to improve the water solubility of poorly hydrosoluble compounds by the formation of inclusion complexes. We employed multiscale (1000 ns) explicit solvent and umbrella sampling molecular dynamics (MD) simulations to study the interactions and thermodynamic parameters of inclusion complex formation between formononetin and five most commonly used β-CD derivatives. Classical MD simulations revealed two possible binding conformations of formononetin inside the central cavity of hydroxypropyl-β-CD (HP-β-CD), randomly methylated-β-CD (ME-β-CD), and sulfobutylether-β-CD (SBE-β-CD). The binding conformation with the benzopyrone ring of formononetin inside the central cavity of β-CD derivatives was more frequent than the phenyl group occupying the hydrophobic cavity. These interactions were supported by a variety of non-bonded contacts including hydrogen bonds, pi-lone pair, pi-sigma, and pi-alkyl interactions. Formononetin showed favorable end-state MD-driven thermodynamic binding free energies with all the selected β-CD derivatives, except succinyl-β-CD (S-β-CD). Furthermore, umbrella sampling simulations were used to investigate the interactions and thermodynamic parameters of the host-guest inclusion complexes. The SBE-β-CD/formononetin inclusion complex showed the lowest binding energy signifying the highest affinity among all the selected host-guest inclusion complexes. Our study could be used as a standard for analyzing and comparing the ability of different β-CD derivatives to enhance the hydro-solubility of poorly soluble molecules.

Cyclodextrin-Based Arsenal for Anti-Cancer Treatments

Anti-cancer drugs are mostly limited in their use due to poor physicochemical and biopharmaceutical properties. Their lower solubility is the most common hurdle limiting their use upto their potential. In the recent years, the cyclodextrin (CD) complexation have emerged as existing approach to overcome the problem of poor solubility. CD-based nano-technological approaches are safe, stable and showed well in vivo tolerance and greater payload for encapsulation of hydrophobic drugs for the targeted delivery. They are generally chosen due to their ability to get self-assembled to form liposomes, nanoparticles, micelles and nano-sponges etc. This review paper describes a birds-eye view of the various CD-based nano-technological approaches applied for the delivery of anti-cancer moieties to the desired target such as CD based liposomes, niosomes, niosoponges, micelles, nanoparticles, monoclonal antibody, magnetic nanoparticles, small interfering RNA, nanorods, miscellaneous formulation of anti-cancer drugs containing CD. Moreover, the author also summarizes the various shortcomings of such a system and their way ahead.

Guest-host Relationship of Cyclodextrin and its Pharmacological Benefits

Many methods, including solid dispersion, micellization, and inclusion complexes, have been employed to increase the solubility of potent drugs. Beta-cyclodextrin (βCD) is a cyclic oligosaccharide consisting of seven glucopyranoside molecules, and is a widely used polymer for formulating soluble inclusion complexes of hydrophobic drugs. The enzymatic activity of Glycosyltransferase or α-amylase converts starch or its derivatives into a mixture of cyclodextrins. The βCD units are characterized by α -(1-4) glucopyranose bonds. Cyclodextrins possess certain properties that make them very distinctive because of their toroidal or truncated cage-like supramolecular configurations with multiple hydroxyl groups at each end. This allowed them to encapsulate hydrophobic compounds by forming inclusion complexes without losing their solubility in water. Chemical modifications and newer derivatives, such as methylated βCD, more soluble hydroxyl propyl methyl βCD, and sodium salts of sulfobutylether-βCD, known as dexolve® or captisol®, have envisaged the use of CDs in various pharmaceutical, medical, and cosmetic industries. The successful inclusion of drug complexes has demonstrated improved solubility, bioavailability, drug resistance reduction, targeting, and penetration across skin and brain tissues. This review encompasses the current applications of β-CDs in improving the disease outcomes of antimicrobials and antifungals as well as anticancer and anti-tubercular drugs.

Hispolon Cyclodextrin Complexes and Their Inclusion in Liposomes for Enhanced Delivery in Melanoma Cell Lines

Hispolon, a phenolic pigment isolated from the mushroom species Phellinus linteus, has been investigated for anti-inflammatory, antioxidant, and anticancer properties; however, low solubility and poor bioavailability have limited its potential clinical translation. In this study, the inclusion complex of hispolon with Sulfobutylether-β-cyclodextrin (SBEβCD) was characterized, and the Hispolon-SBEβCD Complex (HSC) was included within the sterically stabilized liposomes (SL) to further investigate its anticancer activity against melanoma cell lines. The HSC-trapped-Liposome (HSC-SL) formulation was investigated for its sustained drug delivery and enhanced cytotoxicity. The inclusion complex in the solid=state was confirmed by a Job’s plot analysis, molecular modeling, differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), Proton nuclear magnetic resonance (NMR) spectroscopy, and scanning electron microscopy (SEM). The HSC-SL showed no appreciable deviation in size (<150 nm) and polydispersity index (<0.2) and improved drug encapsulation efficiency (>90%) as compared to control hispolon liposomes. Individually incorporated hispolon and SBEβCD in the liposomes (H-CD-SL) was not significant in loading the drug in the liposomes, compared to HSC-SL, as a substantial amount of free drug was separated during dialysis. The HSC-SL formulation showed a sustained release compared to hispolon liposomes (H-SLs) and Hispolon-SBEβCD liposomes (H-CD-SLs). The anticancer activity on melanoma cell lines (B16BL6) of HSC and HSC-SL was higher than in H-CD-SL and hispolon solution. These findings suggest that HSC inclusion in the HSC-SL liposomes stands out as a potential formulation approach for enhancing drug loading, encapsulation, and chemotherapeutic efficiency of hispolon and similar water insoluble drug molecules.

Bicalutamide Anticancer Activity Enhancement by Formulation of Soluble Inclusion Complexes with Cyclodextrins

Bicalutamide (BCL) is a nonsteroidal antiandrogen drug that represents an alternative to castration in the treatment of prostate cancer, due to its relatively long half-life and tolerable side effects. However, it possesses a very low water solubility that can affect its oral bioavailability. In this work, we developed inclusion complexes of BCL with the highly soluble hydroxypropyl-β-cyclodextrin (HP-β-CyD) and sulfobutylether-β-cyclodextrin (SBE-β-CyD) to increase the water solubility and anticancer activity of BCL. The inclusion complexes were prepared using the freeze-drying method and were then characterized in a solid state via differential scanning calorimetry and X-ray analysis and in solution via phase-solubility studies and UV-vis and NMR spectroscopy. The BCL/HP-β-CyD and BCL/SBE-β-CyD inclusion complexes were amorphous and rapidly dissolved in water. Both the 1H-NMR spectra and molecular modeling studies confirmed the penetration of the 2-(trifluoromethyl)benzonitrile ring of BCL within the cavity of both cyclodextrins (CyDs). Due to the consistent improvement of the water solubility of BCL, the inclusion complexes showed higher antiproliferative activity toward the human prostate androgen-independent cell lines, DU-145 and PC-3, with respect to free BCL. These results demonstrate the ability of HP-β-CyD and SBE-β-CyD to complex BCL, permitting the realization of liquid formulations with potentially high oral bioavailability and/or possible parenteral administration.

Development of an Ethanol-Free Salbutamol Sulfate Metered-Dose Inhaler: Application of Molecular Dynamic Simulation-based Prediction of Intermolecular Interaction

INTRODUCTION

More than fifty years after the commercialization of the Ventolin metered-dose inhaler (MDI), its constituent active ingredient, salbutamol sulfate (SS) remains the most prescribed short-acting beta agonist for the first-line treatment of acute asthma attacks and the metered-dose inhaler remains its primary dosage form. The first generation of Ventolin MDI was developed at a time when environmental and regulatory concerns were less stringent than today. The MDI industry is now on the verge of a second major reformulation effort in response to environmental concerns. This paper serves to illustrate how modern computational modeling of molecular interactions can aid the reformulation process. By way of a case study, computational modeling was performed to compare poly(ethylene glycol) 400 (PEG400) and, separately, isopropyl myristate (IPM) as substitutes for the ethanol used in some generic salbutamol sulfate suspension-based hydrofluoroalkane MDIs.

METHODS

PEG400 and isopropyl myristate (IPM) were investigated as potential alternative cosolvents to ethanol in HFA134a-based SS suspension MDI formulations. Density functional theory (DFT) molecular dynamics simulations were used to evaluate the compatibility of the candidate cosolvents with the formulation's components. Corresponding physical formulations were filled into polyethylene terephthalate (PET) and, separately, aluminium canisters. In-vitro pharmaceutical product performance and macroscopic visual appearance were assessed and compared to the results of the simulation studies.

RESULTS

The simulation studies indicated that PEG400 would be a good candidate as a replacement for ethanol whereas IPM would not. The in-vitro and visual assessments support the predicted outcome of the simulation studies.

CONCLUSION

This work suggests that molecular dynamics simulations may provide a useful tool to aid the selection of compatible excipients when reformulating MDI suspension-based products, thereby reducing the time and cost associated with manufacturing and testing of physical samples.

Simple Strategy Preparing Cyclodextrin Carboxylate as a Highly Effective Carrier for Bioactive Compounds

Many phytochemicals suffer from poor water dispersity and storage stability, which restrict their application within aqueous-based commercial products. β-Cyclodextrin (β-CD) is a water-dispersible molecule with a hydrophobic core that can encapsulate and protect non-polar substances. The functional attributes of β-CD can be further enhanced by chemical modification. In this study, a simple and effective dry-heating process was applied to fabricate succinic acid (SA)-modified β-CD (SACD) through esterification. SACD showed better encapsulation property than non-modified β-CD to guest molecules such as methyl orange (up to 1.41-folds of β-CD) and curcumin (with an encapsulation efficiency of up to 10 mg/g). Meanwhile, higher water solubility (up to 469.30 g per 100 g of H₂O) was achieved for SACD, indicating that a high dose of SACD could be applied in an aqueous food matrix. Such a simple strategy exhibiting low cytotoxicity shows great potential incorporating bioactive compounds into functional foods.

Rational formulation engineering of fraxinellone utilizing 6-O-α-D-maltosyl-β-cyclodextrin for enhanced oral bioavailability and hepatic fibrosis therapy

Although Fraxinellone (Frax) isolated from Dictamnus albus L. possessed excellent anti-hepatic fibrosis activity, oral administration of Frax suffered from the inefficient therapeutic outcome in vivo due to negligible oral absorption. At present, the oral formulation of Frax is rarely exploited. For rational formulation design, we evaluated preabsorption risks of Frax and found that Frax was rather stable while poorly dissolved in the gastrointestinal tract (78.88 μg/mL), which predominantly limited its oral absorption. Further solubility test revealed the outstanding capacity of cyclodextrin derivatives (CDs) to solubilize Frax (6.8-12.8 mg/mL). This led us to study the inclusion complexes of Frax with a series of CDs and holistically explore their drug delivery performance. Characterization techniques involving ¹H-NMR, FT-IR, DSC, PXRD, and molecular docking confirmed the most stable binding interactions when Frax complexed with 6-O-α-D-maltosyl-β-cyclodextrin (G₂-β-CD-Frax). Notably, G₂-β-CD-Frax exhibited the highest solubilizing capacity, fast dissolution rate, and superior Caco-2 cell internalization with no obvious toxicity. Pharmacokinetic studies demonstrated markedly higher oral bioavailability of G₂-β-CD-Frax (5.8-fold that of free drug) than other Frax-CDs. Further, long-term administration of G₂-β-CD-Frax (5 mg/kg) efficiently inhibited CCl₄-induced hepatic fibrosis in the mouse without inducing any toxicity. Our results will inspire the continued advancement of optimal oral Frax formulations for anti-fibrotic therapy.

Application of Molecular Dynamics Simulations in the Analysis of Cyclodextrin Complexes

Cyclodextrins (CDs) are highly respected for their ability to form inclusion complexes via host-guest noncovalent interactions and, thus, ensofance other molecular properties. Various molecular modeling methods have found their applications in the analysis of those complexes. However, as showed in this review, molecular dynamics (MD) simulations could provide the information unobtainable by any other means. It is therefore not surprising that published works on MD simulations used in this field have rapidly increased since the early 2010s. This review provides an overview of the successful applications of MD simulations in the studies on CD complexes. Information that is crucial for MD simulations, such as application of force fields, the length of the simulation, or solvent treatment method, are thoroughly discussed. Therefore, this work can serve as a guide to properly set up such calculations and analyze their results.

Development of Chitosan/Cyclodextrin Nanospheres for Levofloxacin Ocular Delivery

Levofloxacin (LVF) is an antibacterial drug approved for the treatment of ocular infections. However, due to the low ocular bioavailability, high doses are needed, causing bacterial resistance. Polymeric nanospheres (NPs) loading antibiotic drugs represent the most promising approach to eradicate ocular infections and to treat pathogen resistance. In this study, we have developed chitosan NPs based on sulfobutyl-ether-β-cyclodextrin (CH/SBE-β-CD NPs) for ocular delivery of LVF. CH/SBE-β-CD NPs loading LVF were characterized in terms of encapsulation parameters, morphology, and sizes, in comparison to NPs produced without the macrocycle. Nuclear magnetic resonance and UV–vis spectroscopy studies demonstrated that SBE-β-CD is able to complex LVF and to influence encapsulation parameters of NPs, producing high encapsulation efficiency and LVF loading. The NPs were homogenous in size, with a hydrodynamic radius between 80 and 170 nm and positive zeta potential (ζ) values. This surface property could promote the interaction of NPs with the negatively charged ocular tissue, increasing their residence time and, consequently, LVF efficacy. In vitro, antibacterial activity against Gram-positive and Gram-negative bacteria showed a double higher activity of CH/SBE-β-CD NPs loading LVF compared to the free drug, suggesting that chitosan NPs based on SBE-β-CD could be a useful system for the treatment of ocular infections.

Cyclodextrin Monomers and Polymers for Drug Activity Enhancement

Cyclodextrins (CDs) and cyclodextrin (CD)-based polymers are well-known complexing agents. One of their distinctive features is to increase the quantity of a drug in a solution or improve its delivery. However, in certain instances, the activity of the solutions is increased not only due to the increase of the drug dose but also due to the drug complexation. Based on numerous studies reviewed, the drug appeared more active in a complex form. This review aims to summarize the performance of CDs and CD-based polymers as activity enhancers. Accordingly, the review is divided into two parts, i.e., the effect of CDs as active drugs and as enhancers in antimicrobials, antivirals, cardiovascular diseases, cancer, neuroprotective agents, and antioxidants.

Cyclodextrins in the antiviral therapy

The main antiviral drug-cyclodextrin interactions, changes in physicochemical and physiological properties of the most commonly used virucides are summarized. The potential complexation of antiviral molecules against the SARS-Cov2 also pointed out the lack of detailed information in designing effective and general medicines against viral infections. The principal problem of the current molecules is the 3D structures of the currently active compounds. Improving the solubility or bioavailability of antiviral molecules is possible, however, there is no universal solution, and the complexation experiments dominantly use the already approved cyclodextrin derivatives. This review discusses the basic properties of the different cyclodextrin derivatives, their potential in antiviral formulations, and the prevention and treatment of viral infections. The biologically active new cyclodextrin derivatives are also discussed.

Inclusion Complexes of Non-Steroidal Anti-Inflammatory Drugs with Cyclodextrins: A Systematic Review

Non-steroidal anti-inflammatory drugs (NSAIDs) are one of the most widely used classes of medicines in the treatment of inflammation, fever, and pain. However, evidence has demonstrated that these drugs can induce significant toxicity. In the search for innovative strategies to overcome NSAID-related problems, the incorporation of drugs into cyclodextrins (CDs) has demonstrated promising results. This study aims to review the impact of cyclodextrin incorporation on the biopharmaceutical and pharmacological properties of non-steroidal anti-inflammatory drugs. A systematic search for papers published between 2010 and 2020 was carried out using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol and the following search terms: “Complexation”; AND “Cyclodextrin”; AND “non-steroidal anti-inflammatory drug”. A total of 24 different NSAIDs, 12 types of CDs, and 60 distinct inclusion complexes were identified, with meloxicam and β-CD appearing in most studies. The results of the present review suggest that CDs are drug delivery systems capable of improving the pharmacological and biopharmaceutical properties of non-steroidal anti-inflammatory drugs.

Anti-Tumor Efficiency of Perillylalcohol/β-Cyclodextrin Inclusion Complexes in a Sarcoma S180-Induced Mice Model

The low solubility and high volatility of perillyl alcohol (POH) compromise its bioavailability and potential use as chemotherapeutic drug. In this work, we have evaluated the anticancer activity of POH complexed with β-cyclodextrin (β-CD) using three complexation approaches. Molecular docking suggests the hydrogen-bond between POH and β-cyclodextrin in molar proportion was 1:1. Thermal analysis and Fourier-transform infrared spectroscopy (FTIR) confirmed that the POH was enclosed in the β-CD cavity. Also, there was a significant reduction of particle size thereof, indicating a modification of the β-cyclodextrin crystals. The complexes were tested against human L929 fibroblasts after 24 h of incubation showing no signs of cytotoxicity. Concerning the histopathological results, the treatment with POH/β-CD at a dose of 50 mg/kg promoted approximately 60% inhibition of tumor growth in a sarcoma S180-induced mice model and the reduction of nuclear immunoexpression of the Ki67 antigen compared to the control group. Obtained data suggest a significant reduction of cycling cells and tumor proliferation. Our results confirm that complexation of POH/β-CD not only solves the problem related to the volatility of the monoterpene but also increases its efficiency as an antitumor agent.

Cytotoxic and Apoptotic Effects of Celecoxib and Topotecan on AGS and HEK 293 Cell Lines

PURPOSE

This study is aimed to assess the anti-cancer effects of Celecoxib and topotecan against Human Gastric cancer cell line (AGS) in comparison to the control in an in-vitro study.

METHODS

In this experimental study, Celecoxib and topotecan was prepared at concentrations of 500, 250, 125, 62.5, 31.2, 15.6 and 7.8 mg/ml. The effect of celecoxib and topotecan separately and in mixed form were investigated on AGS and normal HEK cells. To investigate the cell survival, MTT method was used to study the pathway of apoptosis using flowcytometry and Caspase kits based on colorimetric. Finally, one-way ANOVA and t-test were used to analyze the data.

RESULTS

The results of this study indicated that Celecoxib was cytotoxic against AGS and HEK cell lines. The topotecan indicated a significant cytotoxicity against AGS cells and was not toxic against HEK cell line. Our results indicated that Celecoxib and topotecan have synergist effects against AGS and HEK cell lines and were more effective than separate celecoxib or topotecan.

CONCLUSION

The mixture of clecoxib and topotecan was more effective than celecoxib and topotecan in separate form. Our results indicated that use mixed forms of treatments can cause excellent therapeutic effects and can cause less side effects.

Contemporary Formulation Development for Inhaled Pharmaceuticals

Pulmonary delivery has gained increased interests over the past few decades. For respiratory conditions, targeted drug delivery directly to the site of action can achieve a high local concentration for efficacy with reduced systemic exposure and adverse effects. For systemic conditions, the unique physiology of the lung evolutionarily designed for rapid gaseous exchange presents an entry route for systemic drug delivery. Although the development of inhaled formulations has come a long way over the last few decades, many aspects of it remain to be elucidated. In particular, a reliable and well-understood method for in vitro-in vivo correlations remains to be established. With the rapid and ongoing advancement of technology, there is much potential to better utilise computational methods including different types of modelling and simulation approaches to support inhaled formulation development. This review intends to provide an introduction on some fundamental concepts in pulmonary drug delivery and inhaled formulation development followed by discussions on some challenges and opportunities in the translation of inhaled pharmaceuticals from preclinical studies to clinical development. The review concludes with some recent advancements in modelling and simulation approaches that could play an increasingly important role in modern formulation development of inhaled pharmaceuticals.

Combined chemotherapy with cyclooxygenase-2 (COX-2) inhibitors in treating human cancers: Recent advancement

Chemotherapy with a single chemotherapeutic agent or a combined chemotherapeutic regimen is the clinically standardized treatment for almost all human cancers. Upregulated expression of cyclooxygenase (COX)-2, also known as prostaglandin-endoperoxide synthase (PTGS), is associated with human carcinogenesis and cancer progression and COX-2 inhibitors show antitumor activity in different human cancers. Thus, a combination of chemotherapeutic agents with COX-2 inhibitors has been shown to improve therapeutic effects on human cancers. This review discusses and summarizes recent advances in cancer control and treatment using various antineoplastic drugs combined with COX-2 inhibitors. These combinations showed synergistic antitumor effects. At the gene level, COX-2 inhibitors can reduce inflammatory factors thereby regulating macrophage recruitment for activating the antitumor immune microenvironment; downregulating vascular endothelial growth factor (VEGF) to inhibit tumor angiogenesis; and inhibiting the PI3K/Akt signaling pathway to induce tumor cell apoptosis. In addition, such a combination can reduce toxicity and chemoresistance and enhance radiosensitivity, although COX-2 inhibitors-related cardiotoxicity may potentially affect its use. Further in-depth investigation of these drug combinations is needed to maximize antitumor efficacy and minimize the side effects.

Functionalization of Single and Multi-Walled Carbon Nanotubes with Polypropylene Glycol Decorated Pyrrole for the Development of Doxorubicin Nano-Conveyors for Cancer Drug Delivery

A recently reported functionalization of single and multi-walled carbon nanotubes, based on a cycloaddition reaction between carbon nanotubes and a pyrrole derived compound, was exploited for the formation of a doxorubicin (DOX) stacked drug delivery system. The obtained supramolecular nano-conveyors were characterized by wide-angle X-ray diffraction (WAXD), thermogravimetric analysis (TGA), high-resolution transmission electron microscopy (HR-TEM), and Fourier transform infrared (FT-IR) spectroscopy. The supramolecular interactions were studied by molecular dynamics simulations and by monitoring the emission and the absorption spectra of DOX. Biological studies revealed that two of the synthesized nano-vectors are effectively able to get the drug into the studied cell lines and also to enhance the cell mortality of DOX at a much lower effective dose. This work reports the facile functionalization of carbon nanotubes exploiting the "pyrrole methodology" for the development of novel technological carbon-based drug delivery systems.

Multiple approaches for achieving drug solubility: an in silico perspective

Discovering new therapeutically active molecules is the ultimate destination in pharmaceutical research and development. Most drugs discovered are lipophilic and, hence, exhibit poor aqueous solubility, resulting in low bioavailability. Thus, there is a need to use various solubility enhancement techniques. Computational approaches enable the analysis of drug-carrier interactions or the numerous conformational changes in the carrier matrix that might establish an appropriate balance between cohesive and adhesive stability in a formulation. In this review, we discuss research approaches that provided molecular insight into drugs and their modifiers to unravel their solubility, stability, and bioavailability.

Physicochemical and in vitro cytotoxicity studies of inclusion complex between gemcitabine and cucurbit[7]uril host

Gemcitabine, a cytostatic drug from the pyrimidine antimetabolite group, exhibits limited storage stability and numerous side effects during therapy. One of the strategies to improve the effectiveness of therapy with such drugs is the use of supramolecular nano-containers, including dendrimers and macrocyclic compounds. The ability of gemcitabine to attach a proton in an aqueous environment necessitates the search for a carrier that is well-tolerated by an organism and capable of supramolecular binding of a ligand (drug) in a cationic form. In the current study a promising strategy was tested for using cucurbituril Q7 to bind gemcitabine cations for its efficient intracellular delivery on three selected cancer cell lines (MOLT4, THP-1 and U937). Based on physicochemical studies (equilibrium dialysis, UV and ¹H NMR titrations, DOSY ¹H NMR measurements, DSC calorimetry) and cytotoxicity tests on cells with a free and blocked hENT1 transporter, the conclusion was drawn about the binding and penetration of the cucurbituril-drug complex into cancer cells.