The Increased Dissolution and Oral Absorption of Itraconazole by Nanocrystals with an Endogenous Small-Molecule Surfactant as a Stabilizer

The aim of this study was to develop cholic-acid-stabilized itraconazole nanosuspensions (ITZ-Nanos) with the objective of enhancing drug dissolution and oral absorption. A laboratory-scale microprecipitation-high-pressure homogenization method was employed for the preparation of the ITZ-Nanos, while dynamic light scattering, transmission electron microscope analysis, X-ray diffraction, differential scanning calorimetry, and high-performance liquid chromatography analysis were utilized to evaluate their physicochemical properties. The absorption and bioavailability of the ITZ-Nanos were assessed using Caco-2 cells and rats, with Sporanox® pellets as a comparison. Prior to lyophilization, the particle size of the ITZ-Nanos measured approximately 225.7 nm. Both X-ray diffraction and differential scanning calorimetry confirmed that the ITZ remained crystalline within the nanocrystals. Compared to the pellets, the ITZ-Nanos exhibited significantly higher levels of supersaturation dissolution and demonstrated enhanced drug uptake by the Caco-2 cells. The AUC(0-t) value for the ITZ-Nanos in rats was 1.33-fold higher than that observed for the pellets. These findings suggest that cholic acid holds promise as a stabilizer for ITZ nanocrystals, as well as potentially other nanocrystals.

Bottom-up production of injectable itraconazole suspensions using membrane technology

Bottom-up production of active pharmaceutical ingredient (API) crystal suspensions offers advantages in surface property control and operational ease over top-down methods. However, downstream separation and concentration pose challenges. This proof-of-concept study explores membrane diafiltration as a comprehensive solution for downstream processing of API crystal suspensions produced via anti-solvent crystallization. It involves switching the residual solvent (N-methyl-2-pyrrolidone, NMP) with water, adjusting the excipient (d-α-Tocopherol polyethylene glycol 1000 succinate, TPGS) quantity, and enhancing API loading (solid concentration) in itraconazole crystal suspensions. NMP concentration was decreased from 9 wt% to below 0.05 wt% (in compliance with European Medicine Agency guidelines), while the TPGS concentration was decreased from 0.475 wt% to 0.07 wt%. This reduced the TPGS-to-itraconazole ratio from 1:2 to less than 1:50 and raised the itraconazole loading from 1 wt% to 35.6 wt%. Importantly, these changes did not adversely affect the itraconazole crystal stability in suspension. This study presents membrane diafiltration as a one-step solution to address downstream challenges in bottom-up API crystal suspension production. These findings contribute to optimizing pharmaceutical manufacturing processes and hold promise for advancing the development of long-acting API crystal suspensions via bottom-up production techniques at a commercial scale.

Comprehensive evaluation of polymer types and ratios in Spray-Dried Dispersions: Compaction, Dissolution, and physical stability

Amorphous solid dispersion (ASD) is a well-established strategy for enhancing the solubility and bioavailability of poorly soluble drugs. A significant portion of ASD products are in tablet form. However, the influence of common polymers and drug loading on the manufacturability of ASD tablets remains underexplored. This study focuses on investigating spray-dried ASDs from a tableting perspective by evaluating their physiochemical and mechanical properties. Itraconazole (ITZ) and indomethacin (IND), at the drug loadings ranging from 10% to 50%, were prepared with two polymers, hydroxypropyl methylcellulose acetate succinate (HPMCAS) and polyvinylpyrrolidone (PVP), serving as representative systems. Our findings revealed that increasing the drug loading resulted in a decreased surface area in ITZ-HPMCAS, IND-HPMCAS, and IND-PVP ASDs. However, this trend was not observed in ITZ-PVP dispersions, possibly due to the morphological disparities. Compaction results demonstrated that tabletability improved with decreasing drug loadings, except for ITZ-PVP dispersions. A partial least square analysis underscored particle surface area as the key factor influencing the tensile strength of ASD tablets. Additionally, our study disclosed that ITZ-PVP ASDs exhibited the worst release profiles and stability performance. The comprehensive journey from characterizing ASD particles to analyzing their compaction behavior and investigating drug release and physical stability offered profound insights into the attributes crucial for the downstream processing of amorphous pharmaceuticals.

Development of long-acting injectable suspensions by continuous antisolvent crystallization: An integrated bottom-up process

Our present work elucidated the operational feasibility of direct generation and stabilization of long-acting injectable (LAI) suspensions of a practically insoluble drug, itraconazole (ITZ), by combining continuous liquid antisolvent crystallization with downstream processing (i.e., centrifugal filtration and reconstitution). A novel microchannel reactor-based bottom-up crystallization setup was assembled and optimized for the continuous production of micro-suspension. Based upon the solvent screening and solubility study, N-methyl pyrrolidone (NMP) was selected as the optimal solvent and an impinging jet Y-shaped microchannel reactor (MCR) was selected as the fluidic device to provide a reproducible homogenous mixing environment. Operating parameters such as solvent to antisolvent ratio (S/AS), total jet liquid flow rates (TFRs), ITZ feed solution concentration and the maturation time in spiral tubing were tailored to 1:9 v/v, 50 mL/min, 10 g/100 g solution, and 96 h, respectively. Vitamin E TPGS (0.5% w/w) was found to be the most suitable excipient to stabilize ITZ particles amongst 14 commonly used stabilizers screened. The effect of scaling up from 25 mL to 15 L was evaluated effectively with in situ monitoring of particle size distribution (PSD) and solid-state form. Thereafter, the suspension was subjected to centrifugal filtration to remove excess solvent and increase ITZ solid fraction. As an alternative, an even more concentrated wet pellet was reconstituted with an aqueous solution of 0.5% w/w Vitamin E TPGS as resuspending agent. The ITZ LAI suspension (of 300 mg/mL solid concentration) has the optimal PSD with a D10 of 1.1 ± 0.3 µm, a D50 of 3.53 ± 0.4 µm and a D90 of 6.5 ± 0.8 µm, corroborated by scanning electron microscopy (SEM), as remained stable after 548 days of storage at 25 °C. Finally, in vitro release methods using Dialyzer, dialysis membrane sac were investigated for evaluation of dissolution of ITZ LAI suspensions. The framework presented in this manuscript provides a useful guidance for development of LAI suspensions by an integrated bottom-up approach using ITZ as model API.

Fabrication and optimization of itraconazole-loaded zein-based nanoparticles in coated capsules as a promising colon-targeting approach pursuing opportunistic fungal infections

Itraconazole (ITZ), a broad-spectrum antifungal drug, was formulated into colon-targeting system aiming to treat opportunistic colonic fungal infections that commonly infect chronic inflammatory bowel diseases (IBD) patients due to immunosuppressive therapy. Antisolvent precipitation technique was employed to formulate ITZ-loaded zein nanoparticles (ITZ-ZNPs) using various zein: drug and aqueous:organic phase ratios. Central composite face-centered design (CCFD) was used for statistical analysis and optimization. The optimized formulation was composed of 5.5:1 zein:drug ratio and 9.5:1 aqueous:organic phase ratio with its observed particle size, polydispersity index, zeta potential, and entrapment efficiency of 208 ± 4.29 nm, 0.35 ± 0.04, 35.7 ± 1.65 mV, and 66.78 ± 3.89%, respectively. ITZ-ZNPs were imaged by TEM that revealed spherical core-shell structure, and DSC proved ITZ transformation from crystalline to amorphous form. FT-IR showed coupling of zein NH group with ITZ carbonyl group without affecting ITZ antifungal activity as confirmed by antifungal activity test that showed enhanced activity of ITZ-ZNPs over the pure drug. Histopathological examination and cytotoxicity tests ensured biosafety and tolerance of ITZ-ZNPs to the colon tissue. The optimized formulation was then loaded into Eudragit S100-coated capsules and both in vitro release and in vivo X-ray imaging confirmed the success of such coated capsules in protecting ITZ from the release in stomach and intestine while targeting ITZ to the colon. The study proved that ITZ-ZNPs is promising and safe nanoparticulate system that can protect ITZ throughout the GIT and targeting its release to the colon with effectual focused local action for the treatment of colon fungal infections.

Genetic variations of CYP3A4 on the metabolism of itraconazole in vitro

Itraconazole is a triazole anti-infective drug that has been proven to prevent and treat a variety of fungal and viral infections and has been considered to be a potential therapeutic remedy for COVID-19 treatment. In this study, we aimed to completely evaluate the impacts of Cytochrome P450 3A4 (CYP3A4) variant proteins and drug interactions on the metabolism of itraconazole in recombinant insect microsomes, and to characterize the potential mechanism of substrate selectivity. Incubations with itraconazole (0.2-15 μM) in the presence/absence of lopinavir or darunavir were assessed by CYP3A4 variants, and the metabolite hydroxyitraconazole concentrations were measured by UPLC-MS/MS. Our data showed that when compared with CYP3A4.1, 4 variants (CYP3A4.9, .10, .28 and .34) displayed no significant differences, and 3 variants (CYP3A4.14, .15 and .19) exhibited increased intrinsic clearance (CLint), whereas the remaining 17 variant proteins showed decreased enzyme activities for the catalysis of itraconazole. Moreover, the inhibitory effects of lopinavir and darunavir on itraconazole metabolism varied in different degrees. Furthermore, different changed trend of the kinetic parameters in ten variants (CYP3A4.5, .9, .10, .16, .19, .24, .28, .29, .31, and .33) were observed, especially CYP3A4.5 and CYP3A4.16, and this may be related to the metabolic site-heme iron atom distance. In the present study, we functionally analyzed the effects of 25 CYP3A4 protein variants on itraconazole metabolism for the first time, and provided comprehensive data on itraconazole metabolism in vitro. This may help to better assess the metabolism and elimination of itraconazole in clinic to improve the safety and efficacy of its clinical treatment and also provide new possibilities for the treatment of COVID-19.

Comparative assessment of solubility enhancement of itroconazole by solid dispersion and co-crystallization technique: Investigation of simultaneous effect of media composition on drug dissolution

Solubility of the drug is an important property of the drug as it affects the release, absorption, dissolution rate and ultimately bioavailability of the drug. Hence, the poorly aqueous soluble drug, need to be processed, to enhance its solubility and dissolution. The Biopharmaceutical System of Classification (BCS) II drugs are poorly soluble and have high permeability. Though their good ability to permeate through the membrane make them clinically useful but the problem associated with the solubility restrict their clinical use. Therefore, there is need to improve the solubility of such drug molecules to get effective pharmacological action. Itraconazole (ITZ) is an antifungal agent used in the treatment of fungal infections having poor aqueous solubility as belonging to BCS class II. The present study was aim to enhance the solubility of ITZ by solid dispersion and co-crystallization techniques. Investigation of simultaneous effect of media composition on drug dissolution was also the objective of this work. The ITZ-SD and ITZ-CCs were prepared from ITZ and other excipients like PEG 4000, oxalic acid, fumaric and malic acid by solvent evaporation, kneading technique, slurry conversion and solvent drop grinding methods. The prepared ITZ-SD, ITZ-OA-CCs, ITZ-FA-CCs and ITZ-MA-CCs were evaluated for FTIR, DSC, PXRD, % yield, micromeritic properties. The optimized ITZ-SD and ITZ-CCs were used to compress a tablet and subject to post-compression parameters. The results of FTIR and DSC showed the absence of interaction between the drug and excipients. The PXRD pattern demonstrated the formation of crystalline structures with 6 folds increased in solubility during saturation solubility analysis. In vitro dissolution was carried out in dissolution media with different pH which shows the maximum release from ITZ-SD and ITZ-CCs in pH 6.8. This also revealed the highly pH dependent solubility and dissolution behavior of the weakly basic BCS class II drug (ITZ) with pKa value of 3.7. The overall results in this study indicated the potential of solid dispersion and co-crystals for enhancement of solubility of the poorly water-soluble drugs.

Effect of Shear Strain on the Supercooled Itraconazole

This article investigated the effect of shear strain on the nematic itraconazole (ITR) from both elastic and plastic deformation regions. The rheo-dielectric technique was used for this purpose. It has been demonstrated that shear strain can change the sample color, liquid crystal alignment as well as its dielectric and thermal properties. The observed modifications depend on the shear strain value. One can distinguish four regions regarding the slope of ITR stress-strain dependence and caused changes. Proper alignment changes (obtained after the shearing procedure) can additionally affect the further recrystallization of ITR to other than the initial, i.e., second polymorphic form.

When interactions between bile salts and cyclodextrin cause a negative food effect: Dynamic dissolution/permeation studies with itraconazole (Sporanox®) and biomimetic media

The marketed oral solution of itraconazole (Sporanox®) contains 40% (259.2 mM) of 2-hydroxypropyl-β-cyclodextrin (HP-β-CD). The obvious role of HP-β-CD is to solubilize itraconazole and to overcome its poor aqueous solubility that restricts its absorption. In this study, we investigated the biorelevance of in vitro experiments by the influence of biomimetic media (containing bile salts and phospholipids) on the predicted itraconazole absorption from the commercial HP-β-CD-based Sporanox® solution. We performed phase-solubility studies of itraconazole and dynamic 2-step-dissolution/permeation studies using a biomimetic artificial barrier, Sporanox® solution, and fasted state simulated intestinal fluid (FaSSIF_V1). Both FaSSIF_V1 and HP-β-CD increased the apparent solubility of itraconazole when used individually. In combination, their solubility-enhancing effects were not additive probably due to the competition of bile salts with itraconazole for the hydrophobic cavity of HP-β-CD. Our combined dissolution/permeation experiments indicated the occurrence of a transient supersaturation from Sporanox® upon two-step dissolution. Through systematic variation of bile salt concentrations in the biomimetic media, it was observed that the extent and the duration of supersaturation depend on the concentrations of bile salts: supersaturation was rather stable in the absence of bile salts and phospholipids. The higher the bile salt concentration, the faster the collapse of the transient supersaturation occurred, an effect which is nicely mirrored by reduced in vitro permeation across the barrier. This is an indication of a negative food effect, which in fact correlates well with what earlier had been observed in clinical studies for Sporanox® solution. In essence, we could demonstrate that in vitro two-stage dissolution/permeation experiments using an artificial barrier and selected biomimetic media may predict the negative effects of the latter on cyclodextrin-based drug formulations like Sporanox® Oral Solution and, at the same time, provide a deeper mechanistic insight.

The Pharmacokinetic Effect of Itraconazole and Voriconazole on Ripretinib in Beagle Dogs by UPLC-MS/MS Technique

BACKGROUND

A new UPLC-MS/MS technique for the determination of ripretinib in beagle dog plasma was developed, and the pharmacokinetic effects of voriconazole and itraconazole on ripretinib in beagle dogs were studied.

METHODS

After extraction with ethyl acetate under alkaline conditions, ripretinib was detected using avapritinib as the internal standard (IS). The mobile phases were 0.1% formic acid-acetonitrile. The scanning method was multi-reaction monitoring using ESI+ source, and the ion pairs for ripretinib and IS were m/z 509.93→416.85 and 499.1→482.09, respectively. This animal experiment adopted a three period self-control experimental design. In the first period, ripretinib was orally administered to six beagle dogs at a dose of 5 mg/kg. In the second period, the same six beagle dogs were orally given itraconazole at a dose of 7 mg/kg, after 30 min, ripretinib was orally given. In the third period, voriconazole at a dose of 7 mg/kg was given orally, and then ripretinib was orally given. At different time points, the blood samples were collected. The concentration of ripretinib was detected, and the pharmacokinetic parameters of ripretinib were calculated.

RESULTS

Ripretinib had a good linear relationship in the range of 1-1000 ng/mL. The precision, accuracy, recovery, matrix effect and stability met the requirements of the guiding principles. After erdafitinib combined with itraconazole, the Cmax and AUC0→t of ripretinib increased by 38.35% and 36.36%, respectively, and the t1/2 was prolonged to 7.53 h. After ripretinib combined with voriconazole, the Cmax and AUC0→t of ripretinib increased by 37.44% and 25.52%, respectively, and the t1/2 was prolonged to 7.33 h.

CONCLUSION

A new and reliable UPLC-MS/MS technique was fully optimized and developed to detect the concentration of ripretinib in beagle dog plasma. Itraconazole and voriconazole could inhibit the metabolism of ripretinib in beagle dogs and increase the plasma exposure of ripretinib.

In Silico Structural Modeling and Analysis of Interactions of Tremellomycetes Cytochrome P450 Monooxygenases CYP51s with Substrates and Azoles

Cytochrome P450 monooxygenase CYP51 (sterol 14α-demethylase) is a well-known target of the azole drug fluconazole for treating cryptococcosis, a life-threatening fungal infection in immune-compromised patients in poor countries. Studies indicate that mutations in CYP51 confer fluconazole resistance on cryptococcal species. Despite the importance of CYP51 in these species, few studies on the structural analysis of CYP51 and its interactions with different azole drugs have been reported. We therefore performed in silico structural analysis of 11 CYP51s from cryptococcal species and other Tremellomycetes. Interactions of 11 CYP51s with nine ligands (three substrates and six azoles) performed by Rosetta docking using 10,000 combinations for each of the CYP51-ligand complex (11 CYP51s × 9 ligands = 99 complexes) and hierarchical agglomerative clustering were used for selecting the complexes. A web application for visualization of CYP51s' interactions with ligands was developed (http://bioshell.pl/azoledocking/). The study results indicated that Tremellomycetes CYP51s have a high preference for itraconazole, corroborating the in vitro effectiveness of itraconazole compared to fluconazole. Amino acids interacting with different ligands were found to be conserved across CYP51s, indicating that the procedure employed in this study is accurate and can be automated for studying P450-ligand interactions to cater for the growing number of P450s.

Fabrication and characterization of itraconazole loaded anisotropic solid lipid-mannitol microstructures for enhanced antifungal activity

Anisotropic microparticles containing flower like morphologies have recently attracted significant attention due to their potentially varied application range. Aim of the present work was to build an anisotropic drug delivery system (ASLMMSs) for the encapsulation and enhancement of antifungal activity of a hydrophobic antifungal drug i.e. itraconazole (IRL) with the combination of lipophilic (lipids) as well as hydrophilic (mannitol) materials. Encapsulation efficiency (EE) due to glyceryl monosteatrate (G.ASLMMSs) was 89.02%, whereas Precirol ATO5 formulation (P.ASLMMSs) showed 96.98% EE. FTIR analysis discovered the hydrogen bonding and Vander Waal's forces between lipids and mannitol, while evaluation of XRD data revealed the detailed structural and microstructural characterization indicating the crystallinity of final formulations. Observation under SEM revealed that the final formulations grew in the form of flower like morphologies. These flower-like structures were more obvious for P.ASLMMSs. The increment in dissolution rate (>80% in 6h) could be attributed to the mannitol. Dilutions of Itraconazole loaded anisotropic solid lipid mannitol microstructures (ASLMMSs) in water at concentration range of (500μg/mL, 250μg/mL, 125μg/mL and 75μg/mL) exhibited increased antifungal activity, while free IRL dilution in water showed no zone of inhibition. Both formulations, specifically P.ASLMMSs could signify a promising drug delivery system for lipophilic antifungal drugs.

Bioadhesive-Thermosensitive In Situ Vaginal Gel of the Gel Flake-Solid Dispersion of Itraconazole for Enhanced Antifungal Activity in the Treatment of Vaginal Candidiasis

The poor solubility of itraconazole (ITZ) has limited its efficacy in the treatment of vaginal candidiasis. Accordingly, the improvement of ITZ solubility using a solid dispersion technique was important to enhance its antifungal activity. Besides, as the purpose of this research was to develop local-targeting formulations, bioadhesive-thermosensitive in situ vaginal gel combined with the gel-flake system was found to be the most suitable choice. To obtain optimum solubility, entrapment efficiency, and drug-loading capacity, optimization of solid dispersion (SD) and gel-flake formulations of ITZ was performed using a composite central design. The results showed that the optimized formulation of SD-ITZ was able to significantly enhance its solubility in both water and simulated vaginal fluid to reach the values of 4.211 ± 0.23 and 4.291 ± 0.21 mg/mL, respectively. Additionally, the optimized formulation of SD-ITZ gel flakes possessed desirable entrapment efficiency and drug-loading capacity. The in situ vaginal gel containing SD-ITZ gel flakes was prepared using PF-127 and PF-68, as the gelling agents, with the addition of hydroxypropyl methylcellulose (HPMC) as the mucoadhesive polymer. It was found that the obtained in situ vaginal gel provided desirable physicochemical properties and was able to retain an amount of more than 4 mg of ITZ in the vaginal tissue after 8 h. Importantly, according to the in vivo antifungal activity using infection animal models, the incorporation of the solid dispersion technique and gel-flake system in the formulation of the bioadhesive-thermosensitive in situ vaginal gel led to the most significant decrease of the growth of Candida albicans reaching <1 log colony-forming units (CFU)/mL or equivalent to <10% of the total colony after 14 days, indicating the improvement of ITZ antifungal activity compared to other treated groups. Therefore, these studies confirmed a great potential to enhance the efficacy of ITZ in treating vaginal candidiasis. Following these findings, several further experiments need to be performed to ensure acceptability and usability before the research reaches the clinical stage.

Antifungal Activity of Melaleuca alternifolia Essential Oil (TTO) and Its Synergy with Itraconazole or Ketoconazole against Trichophyton rubrum

Over the past 20–30 years, Trichophyton rubrum represented the most widespread dermatophyte with a prevalence accounting for 70% of dermatophytosis. The treatment for cutaneous infections caused by Trichophyton spp. are imidazoles (ketoconazole (KTZ)) and triazoles (itraconazole (ITZ)). T. rubrum can develop resistance to azoles after prolonged exposure to subinhibitory concentrations resulting in therapeutic failures and chronic infections. These problems have stimulated the search for therapeutic alternatives, including essential oils, and their potential use in combination with conventional antifungals. The purpose of this study was to evaluate the antifungal activity of tea tree oil (TTO) (Melaleuca alternifolia essential oil) and the main components against T. rubrum and to assess whether TTO in association with KTZ/ITZ as reference drugs improves the antifungal activity of these drugs. We used a terpinen-4-ol chemotype (35.88%) TTO, and its antifungal properties were evaluated by minimum inhibitory and minimum fungicidal concentrations in accordance with the CLSI guidelines. The interaction between TTO and azoles was evaluated through the checkerboard and isobologram methods. The results demonstrated both the fungicide activity of TTO on T. rubrum and the synergism when it was used in combination with azoles. Therefore, this mixture may reduce the minimum effective dose of azole required and minimize the side effects of the therapy. Synergy activity offered a promise for combination topical treatment for superficial mycoses.

Kinetics of cytochrome P450 3A4 inhibition by heterocyclic drugs defines a general sequential multistep binding process

Cytochrome P450 (P450) 3A4 is the enzyme most involved in the metabolism of drugs and can also oxidize numerous steroids. This enzyme is also involved in one-half of pharmacokinetic drug-drug interactions, but details of the exact mechanisms of P450 3A4 inhibition are still unclear in many cases. Ketoconazole, clotrimazole, ritonavir, indinavir, and itraconazole are strong inhibitors; analysis of the kinetics of reversal of inhibition with the model substrate 7-benzoyl quinoline showed lag phases in several cases, consistent with multiple structures of P450 3A4 inhibitor complexes. Lags in the onset of inhibition were observed when inhibitors were added to P450 3A4 in 7-benzoyl quinoline O-debenzylation reactions, and similar patterns were observed for inhibition of testosterone 6β-hydroxylation by ritonavir and indinavir. Upon mixing with inhibitors, P450 3A4 showed rapid binding as judged by a spectral shift with at least partial high-spin iron character, followed by a slower conversion to a low-spin iron-nitrogen complex. The changes were best described by two intermediate complexes, one being a partial high-spin form and the second another intermediate, with half-lives of seconds. The kinetics could be modeled in a system involving initial loose binding of inhibitor, followed by a slow step leading to a tighter complex on a multisecond time scale. Although some more complex possibilities cannot be dismissed, these results describe a system in which conformationally distinct forms of P450 3A4 bind inhibitors rapidly and two distinct P450-inhibitor complexes exist en route to the final enzyme-inhibitor complex with full inhibitory activity.

Development of a Method for the Quantification of Clotrimazole and Itraconazole and Study of Their Stability in a New Microemulsion for the Treatment of Sporotrichosis

Sporotrichosis occurs worldwide and is caused by the fungus Sporothrix brasiliensis. This agent has a high zoonotic potential and is transmitted mainly by bites and scratches from infected felines. A new association between the drugs clotrimazole and itraconazole is shown to be effective against S. brasiliensis yeasts. This association was formulated as a microemulsion containing benzyl alcohol as oil, Tween^® 60 and propylene glycol as surfactant and cosurfactant, respectively, and water. Initially, the compatibility between clotrimazole and itraconazole was studied using differential scanning calorimetry (DSC), thermogravimetric analysis (TG), Fourier transform infrared spectroscopy (FTIR), and X-ray powder diffraction (PXRD). Additionally, a simple and efficient analytical HPLC method was developed to simultaneously determine the concentration of clotrimazole and itraconazole in the novel microemulsion. The developed method proved to be efficient, robust, and reproducible for both components of the microemulsion. We also performed an accelerated stability study of this formulation, and the developed analytical method was applied to monitor the content of active ingredients. Interestingly, these investigations led to the detection of a known clotrimazole degradation product whose structure was confirmed using NMR and HRMS, as well as a possible interaction between itraconazole and benzyl alcohol.

Surface Dissolution UV Imaging for Investigation of Dissolution of Poorly Soluble Drugs and Their Amorphous Formulation

The aim of this study is to investigate the dissolution properties of poorly soluble drugs from their pure form and their amorphous formulation under physiological relevant conditions for oral administration based on surface dissolution ultraviolet (UV) imaging. Dissolution of two poorly soluble drugs (cefuroxime axetil and itraconazole) and their amorphous formulations (Zinnat® and Sporanox®) was studied with the Sirius Surface Dissolution Imager (SDI). Media simulating the fasted state conditions (compendial and biorelevant) with sequential media/flow rate change were used. The dissolution mechanism of cefuroxime axetil in simulated gastric fluid (SGF), fasted state simulated gastric fluid (FaSSGF) and simulated intestinal fluid (SIF) is predominantly swelling as opposed to the convective flow in fasted state simulated intestinal fluid (FaSSIF-V1), attributed to the effect of mixed micelles. For the itraconazole compact in biorelevant media, a clear upward diffusion of the dissolved itraconazole into the bulk buffer solution is observed. Dissolution of itraconazole from the Sporanox® compact is affected by the polyethylene glycol (PEG) gelling layer and hydroxypropyl methylcellulose (HPMC) matrix, and a steady diffusional dissolution pattern is revealed. A visual representation and a quantitative assessment of dissolution properties of poorly soluble compounds and their amorphous formulation can be obtained with the use of surface dissolution imaging under in vivo relevant conditions.

Improving Drug Delivery of Micellar Paclitaxel against Non-Small Cell Lung Cancer by Coloading Itraconazole as a Micelle Stabilizer and a Tumor Vascular Manipulator

Although polymeric micelles of paclitaxel (PTX) significantly reduce excipient-induced toxicity compared with Taxol, they exhibit few clinical advantages in tumor inhibition and overall survival. To improve, itraconazole (ITA), an antifungal drug with potent anti-angiogenesis activity, is co-encapsulated together with PTX within the PEG-PLA micelles. The strong intermolecular interactions between the payloads inhibit drug crystallization and prevent drugs from binding with external proteins, render super-stable micelles upon dilution and exposure to biological environment, and enter the tumor cells through endocytosis. The co-encapsulated micelles show strong anti-proliferation potency against non-small-cell lung cancer (NSCLC) and even PTX resistant NSCLC cells in vitro and significantly improve the drug accumulation within the tumor in vivo. Compared with PTX monotherapy or combination therapy using individual PTX and ITA micelles, the co-encapsulated micelle demonstrates strikingly superior efficacy in tumor growth inhibition, recurrence prevention, and reversion of PTX resistance, in Kras mutant patient derived xenografts, orthotropic models, and paclitaxel-resistance subcutaneous models. Besides the pharmacokinetic improvement, therapeutic benefits are also contributed by angiogenesis inhibition and blood vessel normalization by ITA. Utilizing the pharmaceutical and pharmacological synergies between the therapeutic agents, a simple yet effective design of a combination cancer nanomedicine that is industrially scalable and clinically translatable is achieved.

Novel Findings of Anti-Filarial Drug Target and Structure-Based Virtual Screening for Drug Discovery

Lymphatic filariasis and onchocerciasis caused by filarial nematodes are important diseases leading to considerable morbidity throughout tropical countries. Diethylcarbamazine (DEC), albendazole (ALB), and ivermectin (IVM) used in massive drug administration are not highly effective in killing the long-lived adult worms, and there is demand for the development of novel macrofilaricidal drugs affecting new molecular targets. A Ca2+ binding protein, calumenin, was identified as a novel and nematode-specific drug target for filariasis, due to its involvement in fertility and cuticle development in nematodes. As sterilizing and killing effects of the adult worms are considered to be ideal profiles of new drugs, calumenin could be an eligible drug target. Indeed, the Caenorhabditis elegans mutant model of calumenin exhibited enhanced drug acceptability to both microfilaricidal drugs (ALB and IVM) even at the adult stage, proving the roles of the nematode cuticle in efficient drug entry. Molecular modeling revealed that structural features of calumenin were only conserved among nematodes (C. elegans, Brugia malayi, and Onchocerca volvulus). Structural conservation and the specificity of nematode calumenins enabled the development of drugs with good target selectivity between parasites and human hosts. Structure-based virtual screening resulted in the discovery of itraconazole (ITC), an inhibitor of sterol biosynthesis, as a nematode calumenin-targeting ligand. The inhibitory potential of ITC was tested using a nematode mutant model of calumenin.

Application of hydroxypropyl methylcellulose as a protective agent against magnesium stearate induced crystallization of amorphous itraconazole

Itraconazole is a fungicide drug which has low bioavailability due to its poor water solubility. Amorphous solid dispersion (ASD) is a tool that has the potential to greatly increase the dissolution rate and extent of compounds. In this work, the dissolution of tablets containing the ASD of itraconazole with either hydroxypropyl methylcellulose (HPMC) or vinylpyrrolidone-vinyl acetate copolymer (PVPVA) was compared in order to find a formulation which can prevent the drug from the precipitation caused by magnesium stearate. Formulations containing the PVPVA-based ASD with HPMC included in various forms could reach 90% dissolution in 2 h, while HPMC-based ASDs could release 100% of the drug. However, HPMC-based ASD had remarkably poor grindability and low bulk density, which limited its processability and applicability. The latter issue could be resolved by roller compacting the ASD, which significantly increases the bulk density and the flowability of the powder blends used for tableting. This roller compaction step might be a base for the industrial application of HPMC-based, electrospun ASDs.

Determining drug release rates of hydrophobic compounds from nanocarriers

Obtaining meaningful drug release profiles for drug formulations is essential prior to in vivo testing and for ensuring consistent quality. The release kinetics of hydrophobic drugs from nanocarriers (NCs) are not well understood because the standard protocols for maintaining sink conditions and sampling are not valid owing to mass transfer and solubility limitations. In this work, a new in vitroassay protocol based on 'lipid sinks' and magnetic separation produces release conditions that mimic the concentrations of lipid membranes and lipoproteins in vivo, facilitates separation, and thus allows determination of intrinsic release rates of drugs from NCs. The assay protocol is validated by (i) determining the magnetic separation efficiency, (ii) demonstrating that sink condition requirements are met, and (iii) accounting for drug by completing a mass balance. NCs of itraconazole and cyclosporine A (CsA) were prepared and the drug release profiles were determined. This release protocol has been used to compare the drug release from a polymer stabilized NC of CsA to a solid drug NP of CsA alone. These data have led to the finding that stabilizing block copolymer layers have a retarding effect on drug release from NCs, reducing the rate of CsA release fourfold compared with the nanoparticle without a polymer coating.This article is part of the themed issue 'Soft interfacial materials: from fundamentals to formulation'.

Electrochemical behavior of the antifungal agents itraconazole, posaconazole and ketoconazole at a glassy carbon electrode

The electrochemical behavior of the azole antifungal agents itraconazole, posaconazole and ketoconazole has been investigated at a glassy carbon working electrode using cyclic voltammetry. All measurements were carried out in a supporting electrolyte solution consisting of a 1:1 (v/v) mixture of 0.1 mol L(-1) sodium phosphate buffers and acetonitrile at various substance concentrations and pH values. An amperometric cell with a three electrode system consisting of a working electrode, a palladium reference electrode and a platinum disk as the auxiliary electrode was used in all experiments. All azoles showed a similar electrochemical behavior involving two reactions. An irreversible oxidation occurred at potentials of about 0.5V. A reduction peak was detected at potentials between -0.28V and -0.14V with an associated oxidation peak, which was observed in consecutive repeated measurements at potentials between -0.03 and 0.28 V. The reduction and corresponding oxidation can be regarded as a quasi-reversible process. The proposed reaction mechanisms are an irreversible oxidation of the piperazine moiety at higher potentials as well as a reduction at lower potentials of the carbonyl group of the triazolone moiety in the case of itraconazole and posaconazole or a reduction of the methoxy group of ketoconazole.

Solid formulations by a nanocrystal approach: critical process parameters regarding scale-ability of nanocrystals for tableting applications

Nanocrystallization is among the foremost drug delivery platform approaches for the commercial development of poorly soluble drugs. There exists an urge to enable a universal shift of the production of the solid nanocrystal formulations from laboratory scale to industrially feasible scale. The success of any formulation development depends on its transferability to large scale manufacture. The objectives of the study were to increase the nanocrystallization batch size and to screen and optimize parameters for industrially feasible itraconazole (ITC) and indomethacin (IND) nanocrystal composition for tablet formulation. Thus, ITC and IND were transformed into nanocrystal suspensions, using an increased batch size of a wet milling process, freeze-dried, and further developed into both direct compression (DC) and granulated (G) tableting masses. According to the investigated powder and tablet properties (true density, flowability, dose uniformity, maximum upper punch force, crushing strength, dissolution and disintegration) and stability testings, it was clear that the amount of the nanocrystals in the solid tablet formulation is critical in order to fully utilize the benefits of the nanocrystals, i.e., fast dissolution, and to produce high-quality tablets. The DC designs of both the model drugs with compositions including 40% of freeze-dried nanocrystalline drug powder outperformed the corresponding granulated tablets in all parameters after the stability surveillance.

Antifungal activity of a liposomal itraconazole formulation in experimental Aspergillus flavus keratitis with endophthalmitis

The aim of this study was to assess the efficacy of topical application of a liposomal formulation of itraconazole for the treatment of experimental keratitis with endophthalmitis caused by Aspergillus flavus. The liposomes were obtained by the lipid film hydration method followed by sonication. Adult female Wistar rats (weighing 200-220 g) were immunosuppressed by intraperitoneal injection of 150 mg/kg of cyclophosphamide 3 days before infection by exposure to the fungus A. flavus (10(7) spores/ml). Forty-eight hours later, the animals were treated with the liposomal formulation. For comparison, one group of animals (n = 6) was treated with the same drug not encapsulated. At the end of the experiment, the animals were evaluated for clinical signs and number of colony forming units (CFU/g), along with direct microscopic examination. The results indicated that the liposomal formulation of itraconazole has better antifungal activity than the unencapsulated drug in the treatment of fungal keratitis with endophthalmitis caused experimentally by A. flavus in Wistar rats.

Screening methodologies for the development of spray-dried amorphous solid dispersions

PURPOSE

To present a new screening methodology intended to be used in the early development of spray-dried amorphous solid dispersions.

METHODS

A model that combines thermodynamic, kinetic and manufacturing considerations was implemented to obtain estimates of the miscibility and phase behavior of different itraconazole-based solid dispersions. Additionally, a small-scale solvent casting protocol was developed to enable a fast assessment on the amorphous stability of the different drug-polymer systems. Then, solid dispersions at predefined drug loads were produced in a lab-scale spray dryer for powder characterization and comparison of the results generated by the model and solvent cast samples.

RESULTS

The results obtained with the model enabled the ranking of the polymers from a miscibility standpoint. Such ranking was consistent with the experimental data obtained by solvent casting and spray drying. Moreover, the range of optimal drug load determined by the model was as well consistent with the experimental results.

CONCLUSIONS

The screening methodology presented in this work showed that a set of amorphous formulation candidates can be assessed in a computer model, enabling not only the determination of the most suitable polymers, but also of the optimal drug load range to be tested in laboratory experiments. The set of formulation candidates can then be further fine-tuned with solvent casting experiments using a small amount of API, which will then provide the decision for the final candidate formulations to be assessed in spray drying experiments.

Heterostructured layered aluminosilicate-itraconazole nanohybrid for drug delivery system

A nanohybrid, consisting of layered aluminosilicate as a host material and itraconazole as a guest molecule, was successfully synthesized through the interfacial intercalation reaction across the boundary between water and water-immiscible liquid at the various pH. According to the powder X-ray diffraction pattern, the basal spacing of the intraconazole-layered aluminosilicate nanohybrid increased from 14.7 to 22.7 A depending on the pH of the aqueous suspension. The total amounts of itraconazole in the hybrids were determined to be 2.3-25.4 wt% by HPLC analysis. The in vivo pharmacokinetics study was performed in rats in order to compare the absorptions of itraconazole for the itraconazole-layered aluminosilicate nanohybrid and a commercial product, Sporanox. The pharmacokinetic data for the nanohybrid and Sporanox showed that the mean area under the plasma concentration-time curve (AUC, 2477 +/- 898 ng x hr/mL and 2630 +/- 953 ng x hr/mL, respectively) and maximum concentration (Cmax, 225.4 +/- 77.4 ng x hr/mL and 223.6 +/- 51.9 ng x hr/mL, respectively), were within the bioequivalence (BE) range. Therefore, we concluded that this drug-layered aluminosilicate nanohybrid system has a great potential for its application in formulation of poorly soluble drugs.

[Preclinical investigation of pharmaceuticals impact against cytochrome P450 activity and prognosis of substrate affinity as means for providing substrate therapy safety]

Tricyclic antidepressants, not influencing the P450 3A4 activity, are safe in combination with drugs of other groups used in the treatment of comorbid patients. Azaphen is is one of the agents most widely used in the clinical practice. The in vitro electrochemical analysis showed that pipofezin (azaphen) was not a substrate, inductor, and/or inhibitor of cytochrome P450 CYP3A4 isoenzymes. The Guzar programme computer modelling and the literature data demonstrated the substrate affinity of pipifezin to CYP1A2.

Clinical trials with itraconazole as a treatment for chytrid fungal infections in amphibians

Due in large part to recent global declines and extinctions, amphibians are the most threatened vertebrate group. Captive assurance colonies may be the only lifeline for some rapidly disappearing species. Maintaining these colonies free of disease represents a challenge to effective amphibian conservation. The fungal disease chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis (Bd), is one of the major contributors to global amphibian declines and also poses a serious threat to captive assurance colonies. Many treatment options for Bd infection have not been experimentally tested and the commonly administered dosages of some drugs are known to have negative side effects, highlighting a need for clinical trials. The objective of this study was to clinically test the drug itraconazole as a method for curing Bd infection. We bathed Bd-positive juveniles of 2 anuran amphibian species, Litoria caerulea and Incilius nebulifer, in aqueous itraconazole, varying the concentration and duration of treatment, to find the combination that caused the fewest side effects while also reliably ridding animals of Bd. Our results suggest that a bath in 0.0025% itraconazole for 5 min d-1 for 6 d reliably cures Bd infection and causes fewer side effects than the longer treatment times and higher concentrations of this drug that are commonly administered.

Preparation and characterization of fusion processed solid dispersions containing a viscous thermally labile polymeric carrier

The primary aim of the present study was to investigate the ability of hydroxypropyl and methoxyl substituted cellulose ethers to stabilize supersaturated concentrations of itraconazole (ITZ), a poorly water-soluble weak base, after an acid-to-neutral pH transition. A secondary aim of the study was to evaluate the effect of fusion processes on polymer stability and molecular weight. Polymer screening studies showed that stabilization of ITZ supersaturation was related to the molecular weight of the polymer and levels of hydroxypropyl and methoxyl substitution. METHOCEL E50LV (E50LV), which is characterized as having a high melt viscosity, was selected for solid dispersion formulation studies. Hot-melt extrusion processing of E50LV based compositions resulted in high torque loads, low material throughput and polymer degradation. KinetiSol Dispersing, a novel fusion based processing technique, was evaluated as a method to prepare the solid dispersions with reduced levels of polymer degradation. An experimental design revealed that polymer molecular weight was sensitive to shearing forces and high temperatures. However, optimal processing conditions resulted in significantly reduced E50LV degradation relative to HME processing. The technique was effectively utilized to prepare homogenous solid solutions of E50LV and ITZ, characterized as having a single glass transition temperature over a wide range of drug loadings. All prepared compositions provided for a high degree of ITZ supersaturation stabilization.

Tocol modified glycol chitosan for the oral delivery of poorly soluble drugs

The aim of this study was to develop tocol derivatives of chitosan able (i) to self-assemble in the gastrointestinal tract and (ii) to enhance the solubility of poorly soluble drugs. Among the derivatives synthesized, tocopherol succinate glycol chitosan (GC-TOS) conjugates spontaneously formed micelles in aqueous solution with a critical micelle concentration of 2 μg mL(-1). AFM and TEM analysis showed that spherical micelles were formed. The GC-TOS increased water solubility of 2 model class II drugs. GC-TOS loading efficiency was 2.4% (w/w) for ketoconazole and 0.14% (w/w) for itraconazole, respectively. GC-TOS was non-cytotoxic at concentrations up to 10 mg mL(-1). A 3.4-fold increase of the apparent permeation coefficient of ketoconazole across a Caco-2 cell monolayer was demonstrated. Tocol polymer conjugates may be promising vehicles for the oral delivery of poorly soluble drugs.

In vitro antifungal activity and toxicity of itraconazole in DMSA-PLGA nanoparticles

Itraconazole (ITZ) is a drug used to treat various fungal infections and may cause side effects. The aim of this study was to develop and evaluate the in vitro activity of DMSA-PLGA nanoparticles loaded with ITZ against Paracoccidioides brasiliensis, as well as their cytotoxicity. Nanoparticles were prepared using the emulsification-evaporation technique and characterized by their encapsulation efficiency, morphology (TEM), size (Nanosight) and charge (zeta potential). Antifungal efficacy in P. brasiliensis was determined by minimal inhibition concentration (MIC), and cytotoxicity using MTT assay. ITZ was effectively incorporated in the PLGA-DMSA nanoparticles with a loading efficiency of 72.8 +/- 3.50%. The shape was round with a solid polymeric structure, and a size distribution of 174 +/- 86 nm (Average +/- SD). The particles were negatively charged. ITZ-NANO presented antifungal inhibition (MIC = 6.25 ug/mL) against P. brasiliensis and showed lower in vitro cytotoxicity than free drug (ITZ).

Nanosuspension formulation of itraconazole eliminates the negative inotropic effect of SPORANOX in dogs

Previously, it was observed that a nanosuspension formulation of itraconazole was more efficacious and yet less acutely toxic in rats as compared with the conventional solution formulation, SPORANOX (itraconazole) Injection. The present study compares the two formulations with respect to specifically myocardial contractility in conscious dogs. Motivation for doing so is highlighted by the black-box warning in the package insert for SPORANOX (itraconazole) Injection, which warns of negative inotropic effects. Conscious dogs, instrumented with a high-fidelity pressure transducer in the left ventricle, were placed in a sling for dosing and cardiac monitoring. Test and control articles were administered intravenously via a peripheral vein, and left ventricular parameters were measured continuously through 60 min from the start of dosing. As expected, SPORANOX (itraconazole) Injection caused a significant reduction in myocardial contractility as determined by the contractility index. In contrast, the itraconazole nanosuspension administered at twice the dose and at twice the rate of infusion did not result in significant changes in myocardial contractility. A novel formulation technology applied to itraconazole completely prevented the negative inotropic effect observed in conscious dogs as compared with SPORANOX (itraconazole) Injection.

Effect of itraconazoles on the production of pro-inflammatory substances in mouse macrophage-like cells

BACKGROUND, MATERIALS AND METHODS

Synthetic triazoles are widely used for the treatment of fungal infection. In order to understand their possible anti-inflammatory action, we investigated the effect of itraconazole and its hydroxylated derivative (hydroxyitraconazole) on the production of various pro-inflammatory substances by mouse macrophage-like RAW264.7 cells.

RESULTS

These compounds did not apparently show any growth inhibitory or stimulatory effects over a wide range of concentrations (0.2-50 μg/ml). Itraconazoles dose-dependently increased the production of prostaglandin E₂ (PGE₂) and tumor necrosis factor-α (TNF-α) without affecting the production of interleukin-1β (IL-1β) and nitric oxide (NO). LPS treatment significantly enhanced the production of NO, PGE₂, TNF-α and IL-1β. The addition of itraconazoles to LPS-stimulated RAW264.7 cells significantly reduced the production of NO, but rather enhanced the production of PGE₂, TNF-α and IL-1β. ESR spectroscopy demonstrated that itraconazoles did not significantly scavenge NO and superoxide anion radicals, indicating that the inhibition of NO production by itraconazoles is not due to their radical-scavenging activity. Hydroxyitraconazole was slightly more cytostatic, and more efficiently inhibited NO production, but enhanced the production of other pro-inflammatory substances.

CONCLUSION

These data suggest that itraconazoles regulate NO and other pro-inflammatory substances differently in activated macrophages.

Design and evaluation of itraconazole loaded solid lipid nanoparticulate system for improving the antifungal therapy

The objective of the study was to design and evaluate itraconazole loaded solid lipid nanoparticles (SLNs) drug delivery system, where itraconazole nanoparticles with suitable size ranges are expected to improve the therapeutic efficacy and reduction of toxicity of this broad spectrum antifungal agent. Components of the SLNs were lipid (palmitic acid) and surfactants (Pluronic F127 and Tween 40). The itraconazole loaded nanoparticles were prepared by microemulsion dispersion method. Experiments were carried out with optimized ratio of excipients, where drug-lipid ratio and surfactant-cosurfactant ratio (Km) were varied to optimize the formulation characteristics. The effects of dispersion media, its pH, ionic content, etc. were investigated to optimize the SLNs production. Particles size analysis and zeta potential measurements were done using Malvern Mastersizer Hydro 2000G. The particles were also subjected to DSC, IR and XRD analyses. The in vitro drug release profile from nanoparticles was found to prolong up to 12 h. Kinetic analysis of release indicated that nanoparticles formed were matrix in nature, in which Itraconazole dispersed uniformly. Optimized formulations were found to have a lipid-drug ratio of 1.5:1 and prepared at a Km ratio of 1:2 to maximize drug loading, modulate release and minimized particle size. The microemulsion mediated nanoparticle preparation methodology ensured high drug loading (ca. 80%), low and narrow size distribution and provided a reproducible and fast production method. The study elaborates on the feasibility and suitability of lipid based colloidal drug delivery system, employing optimize design to develop a clinically useful nanoparticle system with targeting potential.

Delivery of Itraconazole from Extruded HPC Films

The treatment of onychomycosis by oral delivery is problematic due to the high concentrations required and if available, a topical transcuticular route would be preferred. Towards this end the hot-melt extruded hydroxypropylcellulose based films containing anti-fungal drug itraconazole and alpha-tocopherol topical treatment for onychomycosis were studied. DSC and X-ray measurements did not show a crystalline itraconazole phase indicating the drug is present in the amorphous state. The rate of itraconazole release trended directly with the degree of film hydration and inversely to the hydroxypropylcellulose molecular weight. This results from a higher degree of crystallinity of the HPC films which also changes the release kinetics from first order to zero order as a more tortuous path is created.

Physical state of poorly water soluble therapeutic molecules loaded into SBA-15 ordered mesoporous silica carriers: a case study with itraconazole and ibuprofen

The ordered mesoporous silica material SBA-15 was loaded with the model drugs itraconazole and ibuprofen using three different procedures: (i) adsorption from solution, (ii) incipient wetness impregnation, and (iii) heating of a mixture of drug and SBA-15 powder. The location of the drug molecules in the SBA-15 particles and molecular interactions were investigated using nitrogen adsorption, TGA, DSC, DRS UV-vis, and XPS. The in vitro release of hydrophobic model drugs was evaluated in an aqueous environment simulating gastric fluid. The effectiveness of the loading method was found to be strongly compound dependent. Incipient wetness impregnation using a concentrated itraconazole solution in dichloromethane followed by solvent evaporation was most efficient for dispersing itraconazole in SBA-15. The itraconazole molecules were located on the mesopore walls and inside micropores of the mesopore walls. When SBA-15 was loaded by slurrying it in a diluted itraconazole solution from which the solvent was evaporated, the itraconazole molecules ended up in the mesopores that they plugged locally. At a loading of 30 wt %, itraconazole exhibited intermolecular interactions inside the mesopores revealed by UV spectroscopy and endothermic events traced with DSC. The physical mixing of itraconazole and SBA-15 powder followed by heating above the itraconazole melting temperature resulted in formulations in which glassy itraconazole particles were deposited externally on the SBA-15 particles. Loading with ibuprofen was successful with each of the three loading procedures. Ibuprofen preferably is positioned inside the micropores. In vitro release experiments showed fast release kinetics provided the drug molecules were evenly deposited over the mesoporous surface.

Characterization of Ternary Solid Dispersions of Itraconazole, PEG 6000, and HPMC 2910 E5

In order to reduce the crystallinity of PEG 6000, blends were prepared by spray drying and extrusion with the following polymers; PVP K25, PVPVA 64, and HPMC 2910 E5. The maximal reduction of crystallinity in PEG 6000 was obtained by co-spray drying with HPMC 2910 E5. In the next step the model drug Itraconazole was added to the blend and the resulting ternary solid dispersions were characterized. The results of this study show that the addition of PEG 6000 to the Itraconazole/HPMC 2910 E5 system leads to phase separation that in most cases gives rise to recrystallization of either PEG 6000 or Itraconazole. For all ternary dispersions containing 20% of Itraconazole the drug was highly amorphous and the dissolution was improved compared to the binary 20/80 w/w Itraconazole/HPMC 2910 E5 solid dispersion. For all ternary dispersions containing 40% of Itraconazole, the drug was partially crystalline and the dissolution was lower than the dissolution of the binary 40/60 w/w Itraconazole/HPMC 2910 E5 dispersion. These results show that provided Itraconazole is highly amorphous the addition of PEG 6000 to HPMC 2910 E5 leads to an increase in drug release.

Laponite-based nanohybrid for enhanced solubility and controlled release of itraconazole

Laponite, a form of layered aluminosilicates, and itraconazole, a water insoluble drug, were hybridized through an interfacial reaction at the boundary between water and a water-immiscible liquid. The reaction was carried out under a controlled pH to maintain both physical and chemical stability of the drug. The X-ray diffraction patterns and spectroscopic analyses indicated that itraconazole was intercalated into the interlayer space of clay with a lateral monolayer structure. No significant chemical structural change of itraconazole was seen through the formation of the hybrid. The hybrid system exhibited enhanced solubility and controlled release of itraconazole. The released amount of itraconazole could be controlled in the range from 18 to 75%, depending on the kinds of cations in the release media.

Pharmacokinetics of itraconazole after intravenous and oral dosing of itraconazole‐cyclodextrin formulations

The current research evaluated and compared the efficacy of hydroxybutenyl-beta-cyclodextrin (HBenBCD) and hydroxypropyl-beta-cyclodextrin (HPBCD) as enhancers of itraconazole solubility and oral bioavailability. At 10 wt% cyclodextrin, 17-fold and 3.8-fold increases in itraconazole aqueous solubility were observed in the presence of HBenBCD and HPBCD, respectively. Significant differences in the dissolution of itraconazole in the presence of these two cyclodextrins were also observed. Itraconazole pharmacokinetics is known to exhibit a significant food effect. However, testing in biorelevant media indicated that no food effects should be observed after oral administration of itraconazole:HBenBCD complexes. Formulations of itraconazole with HBenBCD were prepared and these complexes, along with the commercial forms of itraconazole with and without HPBCD (Sporanox) were administered to male Sprague-Dawley rats by oral and intravenous routes. Intravenous administration of itraconazole formulated with HBenBCD resulted in a higher AUC relative to Sporanox. When administered as oral solutions, the itraconazole:HBenBCD formulation provided higher oral bioavailability than the Sporanox oral solution. When administered as solid formulations, the itraconazole:HBenBCD solid formulation provided a 2x increase in oral bioavailability relative to the Sporanox solid formulation. No food effects were observed with the itraconazole:HBenBCD solid dosage forms. Drug/metabolite ratios were dependent upon the dosage form.

Enhancement of dissolution amount and in vivo bioavailability of itraconazole by complexation with β-cyclodextrin using supercritical carbon dioxide

The main objective of this study was to improve the inclusion formation between itraconazole and beta-cyclodextrin and thus enhance dissolution amount and bioavailability characteristics of itraconazole. Inclusion complexes between itraconazole and beta-cyclodextrin were prepared using simple physical mixing, conventional coprecipitation method, and supercritical carbon dioxide (SC CO(2)). Effects of process variables (temperature, pressure) and drug:cyclodextrin ratio on inclusion yield and thermal behavior of the solid complexes prepared by SC CO(2) were studied and compared to those obtained by physical mixing and coprecipitation methods. In addition, dissolution amounts of the products obtained by different methods were measured in gastric fluid. Finally, pharmacokinetic studies of the inclusion complexes were conducted in male Wistar rats to assess the bioavailability of the prepared complexes. Results showed that temperature, pressure and itraconazole:beta-cyclodextrin ratio had significant effects on the inclusion yield of the complex prepared by SC CO(2) method. Higher inclusion yields were obtained in the SC CO(2) method as compared to physical mixing and coprecipitation methods. In vivo drug pharmacokinetic studies showed that the itraconazole-beta-cyclodextrin product prepared using SC CO(2) gave higher bioavailability of itraconazole (in blood, liver and kidney of male Wistar rats) as compared to the products obtained by physical mixing or coprecipitation methods.

Influence of preparation method on itraconazole oral solutions using cyclodextrins as complexing agents

In the literature, solubility values of itraconazole complexed with 2-hydroxypropyl-beta-cyclodextrin (HP-beta-CD) were found which were still much too low to obtain the target concentration of 1 g itraconazole/100 ml, the concentration of the marketed itraconazole formulation Sporanox (Janssen Pharmaceutica). Therefore, we compared two preparation methods: the classical and the dissolving method to investigate if the method of preparation can have an influence on the solubility of itraconazole complexed with cyclodextrin (CD). With the classical method, the active compound and the CDs are jointly dissolved with a co-solvent, propylene glycol, in water. With the dissolving method, the active compound is first dissolved separately in a solvent in which it dissolves well, while the CDs are dissolved in water, before mixing. Three different CDs were used and compared for their complexing capacity with itraconazole. The complex formation of itraconazole with HP-beta-CD, sulfobutylether-7-beta-cyclodextrin (SBE-7-beta-CD) and maltosyl-beta-cyclodextrin (malt-beta-CD) was investigated at pH 2, in the presence of 10% propylene glycol for an oral solution. These three CDs were chosen as they can also serve in formulations for parenteral use. The method of preparation had an important influence on the complex formation. With the dissolving method, a much higher solubility of itraconazole was obtained using the same CD concentration than with the classical method. Inclusion capacity obtained with the dissolving method was comparable for HP-beta-CD and SBE-7-beta-CD: 1 g itraconazole/100 ml of 25% HP-beta-CD or of 30% SBE-7-beta-CD. In 100 ml of 40% malt-beta-CD only about 500 mg of itraconazole could be dissolved. With the classical method only around 160 mg itraconazole could be dissolved with 100 ml 40 % HP-beta-CD or SBE-7-beta-CD. Due to the fast preparation, once the CD amount is known by pretests, the dissolving method shows also an advantage for industrial production.

Itraconazole IV nanosuspension enhances efficacy through altered pharmacokinetics in the rat

The goal of this research was to evaluate an intravenous itraconazole nanosuspension dosage form, relative to a solution formulation, in the rat. Itraconazole was formulated as a nanosuspension by a tandem process of microcrystallization followed by homogenization. Acute toxicity, pharmacokinetics, and distribution were studied in the rat, and compared with a solution formulation of itraconazole. Efficacy was studied in an immunocompromised rat model, challenged with a lethal dose of either itraconazole-sensitive or itraconazole-resistant C. albicans. Itraconazole nanosuspension was tolerated at significantly higher doses compared with a solution formulation. Pharmacokinetics of the nanosuspension were altered relative to the solution formulation. C(max) was reduced and t(1/2) was much prolonged. This occurred due to distribution of the nanosuspension to organs of the monocyte phagocytic system (MPS), followed by sustained release from this IV depot. The higher dosing of the drug, enabled in the case of the nanosuspension, led to higher kidney drug levels and reduced colony counts. Survival was also shown to be superior relative to the solution formulation. Thus, formulation of itraconazole as a nanosuspension enhances efficacy of this antifungal agent relative to a solution formulation, because of altered pharmacokinetics, leading to increased tolerability, permitting higher dosing and resultant tissue drug levels.

Solid dispersions of itraconazole and enteric polymers made by ultra-rapid freezing

The primary objective of the study is to investigate the influence of composition parameters including drug:polymer ratio and polymer type, and particle structure of enteric solid dispersions on the release of ITZ under sink and supersaturated dissolution conditions. Modulated differential scanning calorimetry (MDSC) was utilized to define the level of ITZ miscibility with each polymer. The compositions were completely miscible at 60% ITZ for both polymers and as high as 70% in HP-55. High potency composition glass transition temperatures (T(g)) correlated with predicted T(g)'s from the Gordon-Taylor equation, however, recrystallization exotherms revealed pure amorphous regions indicating that phase separation occurred during particle formation. Furthermore, in vitro studies including X-ray powder diffraction (XRD), scanning electron microscopy (SEM), surface area analysis (BET), and dissolution were performed to determine differences between low potency (completely miscible) and high potency (partially miscible) compositions. Dissolution studies on low potency ITZ compositions revealed that miscibility plays an active role in ITZ release under sink conditions, and square root diffusion through the enteric polymer is observed. Supersaturated dissolution profiles revealed high potency compositions had maximum saturation levels (C/Ceq(max)) between 10.6- and 8-times equilibrium solubility, but had higher cumulative extents of supersaturation, compared to low potency compositions which had C/Ceq(max) values of 15-19.6. However, these low potency compositions rapidly precipitated leading to significantly lower AUCs (p<0.05). The change in the miscibility of the solid dispersion had a pronounced effect of drug release (sink) while differences in potency influenced supersaturated dissolution profiles.

Hot-melt extrusion for enhanced delivery of drug particles

With the recent advent of nanotechnology for pharmaceutical applications, drug particle engineering is the focus of increasing interest as a viable approach for overcoming solubility limitations of poorly water-soluble drugs. Although these particle engineering techniques have been proven successful for enhancing the dissolution properties of many poorly water-soluble drugs, there are limitations associated with them such as particle aggregation, morphological instability, and poor wettability. The aim of this study was to demonstrate a processing technique in which hot-melt extrusion (HME) is utilized to overcome these limitations. Micronized particles of amorphous itraconazole (ITZ) stabilized with PVP or HPMC were produced and subsequently melt extruded with poloxamer 407 and PEO 200 M to deaggregate and disperse the particles into the hydrophilic polymer matrix. Differential scanning calorimetry, X-ray diffraction, and scanning electron microscopy were used to demonstrate that the HME process did not alter the properties of the micronized particles. Dissolution testing conducted at sink conditions revealed that the dissolution rate of the micronized particles was improved by HME due to particle deaggregation and enhanced wetting. Supersaturation dissolution testing demonstrated that the ITZ-HPMC micronized particle extrudates provided superior supersaturation of ITZ compared to the ITZ-PVP micronized particle extrudates. Supersaturation dissolution testing incorporating a pH change (from pH 1.2 to 6.8 at 2 h) revealed that neither micronized particle extrudate formulation significantly reduced the rate of ITZ precipitation from supersaturated solution once pH was increased. Moreover, the two extrudate formulations performed very similarly when only considering dissolution testing from just before pH adjustment through the duration of testing at neutral pH. From oral dosing of rats, it was determined that the two extrudate formulations performed similarly in vivo as confirmed by their statistically equivalent AUC values. By correlating the results of supersaturation dissolution testing with pH change to the in vivo AUC, it appears that rapid precipitation of ITZ occurs upon entrance into the more neutral pH environment of the small intestine resulting in a brief opportunity for absorption. This suggests that perhaps the optimum formulation approach for ITZ is to control drug release so as to retard precipitation as pH is increased and extend the absorption window in the small intestine.

The use of a new hydrophilic polymer, Kollicoat IR®, in the formulation of solid dispersions of Itraconazole

Kollicoat IR, a new pharmaceutical excipient developed as a coating polymer for instant release tablets, was evaluated as a carrier in solid dispersions of Itraconazole. The solid dispersions were prepared by hot stage extrusion. Modulated temperature differential scanning calorimetry and X-ray powder diffraction were used to evaluate the miscibility of the drug and the carrier. The pharmaceutical performance was evaluated by dissolution experiments, performed in simulated gastric fluid without pepsin (SGF(sp)). In the X-ray diffractograms no Itraconazole peaks were visible; the polymer on the other hand appeared to be semi-crystalline. Moreover, its crystallinity increased during the extrusion process due to exposure to heat and shear forces. Modulated temperature differential scanning calorimetry analysis showed that the drug and the polymer formed a two phase system. Separate clusters of glassy Itraconazole were present for drug loads of 40% or higher, indicating further phase separation. Dissolution measurements demonstrated a significantly increased dissolution rate for the solid dispersions compared to physical mixtures. Interestingly the physical mixture made up of glassy Itraconazole and Kollicoat IR (20/80, w/w) showed a dissolution rate and maximum that was much higher than that of the physical mixture made up of crystalline Itraconazole and that of pure glassy Itraconazole. The results of this study show that Kollicoat IR is a promising excipient for the formulation of solid dispersions of Itraconazole prepared by hot stage extrusion.

Evaluation of 227 drugs for in vitro inhibition of cytochrome P450 2B6

Cytochrome P450 2B6 (CYP2B6) is involved in the metabolism of drugs such as bupropion, efavirenz, propofol, and selegiline, among others. More than 200 commonly prescribed drugs and other xenobiotics were examined for their ability to inhibit CYP2B6-mediated bupropion hydroxylase activity. Thirty compounds were found exhibiting greater than 50% inhibition at 30 microM. Inhibitors of CYP2B6 were identified from a wide variety of therapeutic classes. The 2 platelet aggregation inhibitors, clopidogrel and ticlopidine, were both identified as potent inhibitors (IC50 = 0.0206 and 0.149 microM, respectively). Other inhibitors (IC50 < 1 microM) included clotrimazole, itraconazole, sertraline, and raloxifene. These in vitro data were used along with clinical pharmacokinetic information in the prediction of potential drug-drug interactions that could occur by inhibition of CYP2B6. Although few drugs tested are expected to cause drug interactions, clopidogrel and ticlopidine were identified as being of concern as potential inhibitors of clinical relevance. These findings are discussed in context to potential drug interactions that could be observed between these agents and drugs for which CYP2B6 is involved in metabolism.

Turbidimetric measurement and prediction of dissolution rates of poorly soluble drug nanocrystals

Rapid dissolution rates of nanocrystal suspensions of the poorly water-soluble drugs, danazol and itraconazole were measured continuously by in-situ turbidimetry. For pre-wetted suspensions of 300 nm particles, dissolution half-lives as short as a few seconds were determined upon adding surfactant to initiate dissolution. A mass transfer model is presented to determine the particle size distribution and dissolution rate in terms of two steps: interfacial reaction, consisting of micelle uptake and desorption, followed by diffusion of the drug-loaded micelles. The interfacial reaction rate constant, k(S), regressed from turbidity versus time data, in conjunction with the Mie theory of light scattering, was independent of particle size. Therefore, dissolution rate data for micron-sized drug particles, which are widely available, may be used to predict the behavior for submicron particle sizes down to 100 nm. The micellar solubility and k(S) are significantly smaller for itraconazole than danazol, consistent with itraconazole's larger molecular size. For particles smaller than 1 mum, the interfacial reaction resistance was dominant. Since this resistance has received little attention in previous studies, further emphasis on the design of drug nanoparticles with more rapid interfacial reaction offers the possibility of improvements in dissolution rates.

Behavior of itraconazole and benzyl alcohol in aqueous solution containing nonionic surfactants

In order to investigate the behavior of itraconazole and benzyl alcohol in aqueous solution containing surfactants, the distribution of itraconazole and benzyl alcohol between the micellar and aqueous phases was determined and the partition of itraconazole between the hydrophilic and lipophilic moieties in micelles was measured. From these experiments, we can conclude that: (1) in aqueous surfactant solution, itraconazole mainly exists in the micellar phase; (2) the cosolvency effect of benzyl alcohol has a negligible effect on the solubility of itraconazole in aqueous solution; (3) itraconazole tends to align itself in an intermediate position (palisade layer) within the surfactant molecules forming the micelle, which may result in the destruction of the micellar structure; and (4) the precipitation of itraconazole may occur in the process of the exchange of benzyl alcohol between the aqueous and micellar phases. This is the mechanism of destabilization of colloidal drug carriers based on benzyl alcohol.