Preparation and characterization of a synthetic curcumin analog inclusion complex and preliminary evaluation of in vitro antileishmanial activity.

The aim of this work was to prepare and characterize inclusion complexes between a synthetic curcumin analog (dibenzalacetone, DBA) and beta-cyclodextrin (ß-CD); and to evaluate their in vitro antileishmanial activity. DBA was synthetized and characterized by spectroscopic methods and the inclusion complexes were obtained by kneading and lyophilization (LIO) in 1:1 and 1:2 stoichiometries. Phase solubility and dissolution assays showed a 40-fold increase in the aqueous solubility of DBA and its complete dissolution from LIO 1:1 formulation after 120 min respectively. Solid-state characterization by differential scanning calorimetry and near infrared spectroscopy demonstrated the inclusion of DBA in the ß-CD cavity at the molar ratios tested, with LIO 1:1 formulation being the most stable. Using nuclear magnetic resonance experiments, the protons inside the cavity of ß-CD were the most affected after the inclusion of DBA molecule. The cellular viability of THP-1 macrophage cells treated with plain DBA, ß-CD and DBA/CD inclusion complexes showed that the plain DBA and DBA/CD at 1:2 stoichiometry presented toxicity, while ß-CD alone and DBA/CD at 1:1 stoichiometry showed no toxicity up to 640 µg mL-1. The in vitro assay with free-living promastigotes demonstrated that plain DBA and ß-CD had IC50 of < 10 and > 320 µg mL-1 respectively, while only inclusion complexes with 1:1 stoichiometry showed antiproliferative activity with IC50 = 51.3 µg mL-1. Using the amastigote intracellular forms, there was also a difference between the plain and ß-CD complexed DBA with complexes of 1:1 and 1:2 stoichiometry presenting EC50 = 66.3 µg mL-1 and 58.9 µg mL-1 respectively. The study concluded that DBA/CD at 1:1 molar ratio has the potential to decrease the intrinsic toxicity of plain DBA towards Leishmania host cells, which may be a therapeutic advantage in the application of these compounds.

Pyromellitic dianhydride crosslinked soluble cyclodextrin polymers: Synthesis, lopinavir release from sub-micron sized particles and anti-HIV-1 activity.

We report the synthesis of water soluble cyclodextrin (CD) polymers prepared by crosslinking pyromellitic dianhydride (PMDA) with two CD derivatives (methyl-ß-CD - MßCD and (2-hydroxy)propyl-ß-CD - HPßCD) and their evaluation as functional sub-micron sized carriers in the development of antiretroviral drug delivery systems. Using the protease inhibitor lopinavir (LPV) as model drug, LPV loaded CD polymers (pHPßCD and pMßCD) were prepared and fully characterized. The physicochemical characterization and in vitro drug release confirmed the successful synthesis of pHPßCD and pMßCD, the formation of sub-micron sized particles and a 12-14 fold increase in LPV solubility. Cytotoxicity assays indicated that both pHPßCD and pMßCD were able to improve the safety profile of LPV while the viral infectivity assay revealed a concentration independent anti-HIV-1 effect for both pHPßCD and pMßCD with a maximum percentage inhibition (MPI) of 79 and 91% respectively. After LPV loading, the antiviral profile of pHPßCD was reversed to the sigmoidal dose-response profile of LPV, while pMßCD maintained its dose-independent profile followed by a LPV mediated increase in viral inhibition. Overall, both pHPßCD and pMßCD demonstrated anti-HIV-1 activity, while drug loaded pMßCD indicated its potential as functional sub-micron sized drug delivery polymers for achieving synergistic anti-HIV activity.

Orodispersible Carbamazepine/Hydroxypropyl-ß-Cyclodextrin Tablets Obtained by Direct Compression with Five-in-One Co-processed Excipients.

The development of orodispersible tablets (ODTs) for poorly soluble and poorly flowable drugs via direct compression is still a challenge. This work aimed to develop ODTs of poorly soluble drugs by combining cyclodextrins that form inclusion complexes to improve wetting and release properties, and directly compressible co-processed excipients able to promote rapid disintegration and solve the poor flowability typical of inclusion complexes. Carbamazepine (CBZ) and hydroxypropyl-ß-cyclodextrin (HPßCD) were used, respectively, as a model of a poorly soluble drug with poor flowability and as a solubilizing agent. Specifically, CBZ-an antiepileptic and anticonvulsant drug-may benefit from the studied formulation approach, since some patients have swallowing difficulties or fear of choking and are non-cooperative. Prosolv® ODT G2 and F-Melt® type C were the studied five-in-one co-processed excipients. The complex was prepared by kneading. Flow properties of all materials and main properties of the tablets were characterized. The obtained results showed that ODTs containing CBZ/HPßCD complex can be prepared by direct compression through the addition of co-processed excipients. The simultaneous use of co-processing and cyclodextrin technologies rendered ODTs with an in vitro disintegration time in accordance with the European Pharmacopoeia requirement and with a fast and complete drug dissolution. In conclusion, the combination of five-in-one co-processed excipients and hydrophilic cyclodextrins may help addressing the ODT formulation of poorly soluble drugs with poor flowability, by direct compression and with desired release properties.

Cyclodextrin solubilization and complexation of antiretroviral drug lopinavir: In silico prediction; Effects of derivatization, molar ratio and preparation method.

Lopinavir (LPV) is currently used in combination with ritonavir for the clinical management of HIV infections due to its limited oral bioavailability. Herein, we report the application of an in silico method to study cyclodextrin (CyD) host-guest molecular interaction with LPV for the rational selection of the best CyD for developing a CyD based LPV delivery system. The predicted CyD, a (2-hydroxy)propyl-gamma derivative with high degree of substitution (HP17-γ-CyD) was synthesized and comparatively evaluated with γ-CyD and the commercially available HP-γ-CyD. All complexes were prepared by supercritical assisted spray drying (SASD) and co-evaporation (CoEva) at molar ratios (1:1 and 1:2); and afterwards fully characterized. Results indicate a higher LPV amorphization and solubilization ability of HP17-γ-CyD. The SASD processing technology also enhanced LPV solubilization and release from complexes. The application of in silico methodologies is a feasible approach for the rational and/or deductive development of CyD drug delivery systems.

Pharmaceutical Benefits of Fluticasone Propionate Association to Delivery Systems: In Vitro and In Vivo Evaluation.

The objective of the present work was to characterize the ability of liposomes and cyclodextrin (CyD) complexes to modulate the in vivo profile of fluticasone (FTZ). In vitro cell compatibility tests were performed, exposing A549 cells to FTZ in the free form and FTZ associated to liposomes and complexed with CyD. The in vivo fate of a selected FTZ liposomal formulation and of several FTZ CyD complexes was achieved following intranasal instillation or pulmonary administration in BALB/c mice, respectively. For pulmonary administration, an inhalation chamber was constructed to enable the simultaneously pulmonary administration to six mice. Thirty minutes and 3 h after administration, mice were sacrificed, their blood, lungs, livers, and spleens were removed, and FTZ level was determined by HPLC using an extraction procedure. The in vitro tests revealed no toxic effects of FTZ formulations, as cellular viability was always superior to 90% for FTZ concentrations ranging from 5 to 60 µM 72 h after incubation. The in vivo biodistribution results showed that FTZ incorporated in liposomes resulted in 20 and 30 times higher accumulation in the lungs in comparison with free FTZ, at 0.5 and 3 h after i.n. administration, respectively. FTZ associated to Hydroxypropyl-γ-cyclodextrin (HP-CyD) was the complex that permitted the higher accumulation of FTZ in the lungs in comparison with the respective free form. The results also suggest that the inhalation chamber apparatus can effectively facilitate the evaluation of in vivo inhalation. The establishment of an animal model of asthma allows us to further study the therapeutic efficacy of the developed FTZ formulations.

Hydroxypropyl-ß-cyclodextrin-based fast dissolving carbamazepine printlets prepared by semisolid extrusion 3D printing.

This work aimed to explore for the first time the use of cyclodextrins to prepare printlets of poorly soluble drugs, such as carbamazepine, which require fine dose adjustment and rapid release. Orodispersible (flash) and immediate release formulations were 3D printed via semisolid extrusion of wet masses of hydroxypropyl-ß-cyclodextrin (HPßCD) and cellulose ethers and regulating tablet porosity. Rheology of the wet masses allowed identifying printable compositions. Printing robustness was assessed evaluating weight, dimensions, hardness, drug content, and microstructure. Drug crystallinity, printlet disintegration and dissolution profiles were also characterized. The results highlight the feasibility of using HPßCD as excipient in printlets of poorly soluble drugs, and the possibilities of tuning drug release profiles through small changes in cellulose ethers nature and ratio. Semisolid extrusion-based 3D printing is revealed as a feasible approach to in situ form carbamazepine-HPßCD complexes and to produce printlets with suitable physical and drug release properties for oral delivery.

Hydroxypropyl-ß-Cyclodextrin and ß-Cyclodextrin as Tablet Fillers for Direct Compression.

Cyclodextrins are cyclic carbohydrates widely used as complexing and non-complexing excipients in drug delivery systems. The purpose of this work was to study the ability of hydroxypropyl-ß-cyclodextrin and ß-cyclodextrin to act as tablet fillers for direct compression. In this way, several parameters of the cyclodextrins were evaluated, namely: (i) the flow properties such as angle of repose, flow time, Carr index, and Hausner ratio; (ii) the compaction behavior, specifically the energies and forces exerted during tableting, the plasticity index, the lubrication efficiency, and compression profiles (force/time and work/displacement of the upper punch); and (iii) the influence on carbamazepine release characteristics from uncoated tablets, i.e., dissolution rate and disintegration time. In addition, these properties of the cyclodextrins were compared with those from other commonly used direct compression fillers (lactose monohydrate, mannitol, calcium hydrogen phosphate dihydrate, and microcrystalline cellulose) and co-processed excipients (microcrystalline cellulose/mannitol and lactose monohydrate/cellulose). Three main conclusions can be drawn: (i) the studied cyclodextrins can be used as tablet fillers for direct compression; (ii) hydroxypropyl-ß-cyclodextrin showed better properties than ß-cyclodextrin mainly at the level of the physics of compression (higher values of plasticity index and lubrication efficiency) and of the drug release characteristics (faster and greater dissolution rate and a shorter disintegration time); and (iii) lactose monohydrate and hydroxypropyl-ß-cyclodextrin displayed the best results. As there are people intolerant to lactose, hydroxypropyl-ß-cyclodextrin, although its cost is higher, can be considered a good substitute for lactose.

Cyclodextrins as excipients in tablet formulations.

This paper aims to provide a critical review of cyclodextrins as excipients in tablet formulations, highlighting: (i) the principal pharmaceutical applications of cyclodextrins; (ii) the most relevant technological aspects in pharmaceutical formulation development; and (iii) the actual regulatory status of cyclodextrins. Moreover, several illustrative examples are presented. Cyclodextrins can be used as complexing excipients in tablet formulations for low-dose drugs. By contrast, for medium-dose drugs and/or when the complexation efficiency is low, the methods to enhance the complexation efficiency play a key part in reducing the cyclodextrin quantity. In addition, these compounds are used as fillers, disintegrants, binders and multifunctional direct compression excipients of the tablets.

Cyclodextrins as Drug Carriers in Pharmaceutical Technology: The State of the Art.

BACKGROUND: Cyclodextrins (CDs) are versatile excipients with an essential role in drug delivery, as they can form non-covalently bonded inclusion complexes (host-guest complexes) with several drugs either in solution or in the solid state. METHODS: The main purpose of this publication was to carry out a state of the art of CDs as complexing agents in drug carrier systems. In this way, the history, properties and pharmaceutical applications of the CDs were highlighted with typical examples. The methods to enhance the Complexation Efficiency (CE) and the CDs applications in solid dosage forms were emphasized in more detail. RESULTS: The main advantages of using these cyclic oligosaccharides are as follows: (1) to enhance solubility/ dissolution/ bioavailability of poorly soluble drugs; (2) to enhance drug stability; (3) to modify the drug release site and/or time profile; and (4) to reduce drug side effects (for example, gastric or ocular irritation). These compounds present favorable toxicological profile for human use and therefore there are various medicines containing CDs approved by regulatory authorities worldwide. On the other hand, the major drawback of CDs is the increase in formulation bulk, once the CE is, in general, very low. This aspect is particularly relevant in solid dosage forms and limits the use of CDs to potent drugs. CONCLUSION: CDs have great potential as drug carriers in Pharmaceutical Technology and can be used by the formulator in order to improve the drug properties such as solubility, bioavailability and stability. Additionally, recent studies have shown that these compounds can be applied as active pharmaceutical ingredients.

Cyclodextrin nanosystems in oral drug delivery: A mini review.

Oral delivery of many therapeutic agents remains challenging due to gastric insolubility/poor dissolution, inefficient intestinal permeability and pre-systemic inactivation. These problems limit the advantages of convenience and increased compliance they provide in the therapy of many chronic diseases. Cyclodextrin nanosystems have emerged as promising platforms for drug-specific construction of the oral delivery nanosystems able to optimize the desired physicochemical properties and pharmacokinetic parameters; without a compromise on safety. This review focuses on some recent and encouraging advances in the application of cyclodextrin nanosystems for oral drug delivery. A general overview of cyclodextrins and pharmaceutical nanotechnology in oral delivery systems is provided. Some of the strategies being exploited for the synthesis of these nanosystems, and their potential for the intelligent navigation of the gastrointestinal tract for optimal bioavailability and biodistribution are then illustrated. Perspectives for translating these nanosystems from laboratory efficient formulations to clinically useful medicines are also discussed.

The Effect of Lycopene Preexposure on UV-B-Irradiated Human Keratinocytes.

Lycopene has been reported as the antioxidant most quickly depleted in skin upon UV irradiation, and thus it might play a protective role. Our goal was to investigate the effects of preexposure to lycopene on UV-B-irradiated skin cells. Cells were exposed for 24 h to 10 M lycopene, and subsequently irradiated and left to recover for another 24 h period. Thereafter, several parameters were analyzed by FCM and RT-PCR: genotoxicity/clastogenicity by assessing the cell cycle distribution; apoptosis by performing the Annexin-V assay and analyzing gene expression of apoptosis biomarkers; and oxidative stress by ROS quantification. Lycopene did not significantly affect the profile of apoptotic, necrotic and viable cells in nonirradiated cells neither showed cytostatic effects. However, irradiated cells previously treated with lycopene showed an increase in both dead and viable subpopulations compared to nonexposed irradiated cells. In irradiated cells, lycopene preexposure resulted in overexpression of BAX gene compared to nonexposed irradiated cells. This was accompanied by a cell cycle delay at S-phase transition and consequent decrease of cells in G0/G1 phase. Thus, lycopene seems to play a corrective role in irradiated cells depending on the level of photodamage. Thus, our findings may have implications for the management of skin cancer.

Validation of an HPLC Analytical Method for the Quantitative/Qualitative Determination of Fluticasone Propionate in Inhalation Particles on Several Matrices.

Fluticasone propionate is a highly potent corticosteroid used to treat asthma and allergic rhinitis. It is a very effective drug, but has the inconvenient factor of being insoluble in water. Cyclodextrins were used to improve this limitation because of their ability to form inclusion complexes with guest drug molecules as well as increase the stability and bioavailability of the drugs. A rapid and simple HPLC method was developed to detect and quantify fluticasone propionate in inhalation particles on several matrices. Liquid chromatography with a UV detector at a wavelength of 236 nm, using a C18 column, was employed in this study. Isocratic elution was employed using a mixture of acetonitrile and water (60:40, v/v). The analytical method validation was performed in accordance with ICH guidelines, which included selectivity, range, linearity, accuracy, detection limit, quantitation limit, precision, robustness, and stability of solutions. This method showed to be selective and specific. Acceptable assay precision and accuracy (100 ± 5.0%) were obtained at 50- 150% of the analytical concentration of fluticasone propionate at the target concentration of 0.060 mg/mL, and good linearity (0.9958) was achieved over a range of 0.03 to 0.09 mg/mL for fluticasone propionate. The proposed HPLC method proved to be reliable. The validation and application of this method can be adopted for determining the fluticasone propionate in: assays, impingers and impactors, diffusion cells, dissolutions, and other tests. In addition, this method can be adapted and used in the pharmaceutical industry for routine analysis.

Optimisation of spray-drying process variables for dry powder inhalation (DPI) formulations of corticosteroid/cyclodextrin inclusion complexes.

This study aims to develop and characterise a beclomethasone diproprionate:gamma-cyclodextrin (BDP:gamma-CYD) complex and to optimise the variables on the spray-drying process, in order to obtain a powder with the most suitable characteristics for lung delivery. The spray-dried powder--in a mass ratio of 2:5 (BDP:gamma-CYD)--was physically mixed with three carriers of different particle sizes and in different ratios. Particle-size distribution, shape and morphology, moisture content, and uniformity in BDP content of formulations were studied. In vitro aerolisation behaviour of the formulations was evaluated using the Rotahaler, and the performance was characterised based on the uniformity of emitted dose and aerodynamic particle-size distribution (respirable fraction (RF), as a percentage of nominal dose (RFN) and emitted dose (RFE)). The most suitable conditions for the preparation of BDP:gamma-CYD complexes were obtained with the solution flow of 5 ml/min, T(in) of 70 degrees C and T(out) of 50 degrees C. Statistically significant differences in the aerodynamic performances were obtained for formulations containing BDP:gamma-CYD complexes prepared using different solution flows and different T(in) (p<0.05). RFN and RFE vary in direct proportion with T(in), while an inverse relationship was observed for the solution flow. A direct correlation between the RFE and the T(out) was identified. Performance of the formulations was compared with an established commercial product (Beclotaide Rotacaps 100 microg) with improved performance of RF: formulations with respitose carrier attained RFN and RFE twofold greater, and formulations based on 63-90 microm fraction lactose and trehalose achieved a threefold improvement; also, all formulations showed that the percentage of dose of BDP deposited in the "oropharynx" compartment was reduced to half.