Modification of MM force fields around heme-Fe in the CYP-ligand complex and ab initio FMO calculations for the complex.

Cytochrome P450 (CYP) enzymes play essential roles in the synthesis and metabolic activation of physiologically active substances. CYP has a prosthetic heme (iron protoporphyrin IX) in its active center, where Fe ion (heme-Fe) is deeply involved in enzymatic reactions of CYP. To precisely describe the structure and electronic states around heme-Fe, we modified the force fields (FFs) around heme-Fe in molecular mechanics (MM) simulations and conducted ab initio fragment molecular orbital (FMO) calculations for the CYP-ligand complex. To describe the coordination bond between heme-Fe and its coordinated ligand (ketoconazole), we added FF between heme-Fe and the N atom of ketoconazole, and then the structure of the complex was optimized using the modified FF. Its adequacy was confirmed by comparing the MM-optimized structure with the X-ray crystal one of the CYP-ketoconazole complex. We also performed 100 ns molecular dynamics simulations and revealed that the coordination bonds around heme-Fe were maintained even at 310 K and that the CYP-ketoconazole structure was kept similar to the X-ray structure. Furthermore, we investigated the electronic states of the complex using the ab initio FMO method to identify the CYP residues and parts of ketoconazole that contribute to strong binding between CYP and ketoconazole. The present procedure of constructing FF between heme-Fe and ketoconazole can be applicable to other CYP-ligand complexes, and the modified FF can provide their accurate structures useful for predicting the specific interactions between CYP and its ligands.

Amphiphilic disodium glycyrrhizin as a co-former for ketoconazole co-amorphous systems: Biopharmaceutical properties and underlying molecular mechanisms.

Co-amorphous systems (CAMs) have been extensively investigated to improve the dissolution of hydrophobic drugs. However, drug precipitation during the storage or dissolution of CAMs has still been a major challenge. Here, disodium glycyrrhizin (Na2GA) was first used as a co-former in CAMs based on its multiple hydroxyl groups and amphiphilic structure. Ketoconazole (KTZ), a BCS class II drug, was selected as a model drug. KTZ-Na2GA CAMs at mass ratios of 1:1, 1:2.5, 1:5 and 1:10 were prepared by the spray drying method and further characterised by PXRD and DSC. The 1:2.5, 1:5 and 1:10 groups exhibited significantly enhanced Cmax (all approximately 26.67-fold) and stable maintenance of supersaturation compared to the crystalline KTZ and the corresponding physical mixtures in non-sink dissolution tests, while the 1:1 group exhibited an unstable medium Cmax (all approximately 14.67-fold). The permeability tests revealed that the permeation rate of KTZ in KTZ-Na2GA CAMs under the concentration of Na2GA in solution above the critical micelle concentration (CMC) showed a significant downwards trend compared to that below CMC. The underlying molecular mechanisms were involved in molecular miscibility, hydrogen bond interactions, solubilisation and crystallisation inhibition by Na2GA. Pharmacokinetic studies demonstrated that the AUC0-∞ of KTZ in 1:1, 1:2.5, 1:5 and 1:10 groups were significantly higher than those of the crystalline KTZ group with 2.13-, 2.30-, 2.16- and 1.86-fold, respectively (p < 0.01). In conclusion, Na2GA has proven to be a promising co-former in CAMs to enhance hydrophobic drug dissolution and bioavailability. Its effect on intestinal permeation rate of drugs also deserves attention.

Ketoconazole Shampoo for Seborrheic Dermatitis of the Scalp: A Narrative Review.

Seborrheic dermatitis (SD) is a common inflammatory skin condition characterized by itchy, sensitive patches of greasy, flaky skin in areas rich in sebaceous glands, such as the scalp. Cases range from asymptomatic to debilitating, with effective treatment in severe cases proving crucial to patient quality of life. Ketoconazole shampoo is a topical antifungal that is a promising treatment option for individuals affected by this condition.Numerous trials display significant improvement in irritation and scaling of scalp seborrheic dermatitis (SSD) with ketoconazole shampoo treatment. Most studies also report optimally low relapse rates as well as little to no side effects, including rare skin irritation that resolves with cessation of the drug. Based on these findings, ketoconazole shampoo seems to be a safe and effective treatment for SSD.The present investigation reviews knowledge and research regarding ketoconazole shampoo as a treatment for SSD for physician consideration in the clinical setting.

Now that griseofulvin is not available, what to do with tinea capitis treatments?

INTRODUCTION: Griseofulvin, discovered in 1939 and commercially available since 1959, was the first oral antifungal agent effective against dermatophytosis, particularly tinea capitis. Although it was eventually superseded by azole antifungals due to its long treatment duration and reliance on keratopoiesis, griseofulvin remains notable for its effectiveness and safety in treating tinea capitis, especially when caused by Microsporum canis. However, due to a decline in cases and commercial unavailability, alternative treatments are now required. AREAS COVERED: The following topics regarding to other treatments were discussed: (I) The efficacy of alternative antifungal agents such as terbinafine, itraconazole, and fluconazole, in the treatment of tinea capitis. (II) The use and role of topical therapies. (III) Experience in the management of tinea capitis. EXPERT OPINION: The usefulness of oral terbinafine as a replacement for griseofulvin in the treatment of tinea capitis and why it is the preferred drug in elderly patients was discussed. Challenges with Microsporum spp. and the use of fluconazole in pediatric patients were also analyzed. Support for the use of topical treatment as an adjunctive treatment for tinea capitis was highlighted.

Minor changes to circulating steroid hormones in female rats after perinatal exposure to diethylstilbestrol or ketoconazole.

Current chemical test strategies lack sensitive markers for detecting female reproductive toxicity caused by endocrine disrupting chemicals (EDCs). In search of a potentially sensitive readout, the steroidogenic disrupting effects of the well-known EDCs ketoconazole (KTZ) and diethylstilbestrol (DES) were investigated in vitro and on circulating steroid hormones in perinatally exposed female Sprague-Dawley rats. Twenty-one steroid hormones were analysed using LC-MS/MS in plasma from female rat offspring at postnatal day (PD) 6, 14, 22, 42 and 90. Most circulating steroid hormone levels increased with age except for estrone (E1), estradiol (E2) and backdoor pathway androsterone (ANDROST), which decreased after PD 22. Perinatal exposure to DES did not affect circulating steroid hormone levels at any dose or age compared to controls. KTZ exposure resulted in dose-dependent increase of corticosterone (CORTICO) at PD 6 and PD 14, with statistical significance only at PD 14. In the in vitro gold standard H295R steroidogenesis assay, twenty-one steroid hormones were measured instead of only T and E2. DES had subtle effects on steroidogenesis, whereas KTZ decreased most steroid hormones, but increased CORTICO, progesterone (P4), estriol (E3) initially (around 0.1-1µM) before decreasing. Our data suggests that circulating steroidomic profiling may not be a sensitive readout for EDC-induced female reproductive toxicity. Further studies are needed to associate H295R assay steroidomic profiles with in vivo profiles, especially in target tissues such as adrenals or gonads. Expanding the H295R steroidogenic assay to include a comprehensive steroidomic profile may enhance its regulatory applicability.

Enhancing Retinoic Acid-mediated Effects Through Inhibition of CYP26A1, CYP26B1 and HGF Signaling in Neuroblastoma Cells.

BACKGROUND/AIM: Retinoic acid (RA) induces tumor cell differentiation in diseases like acute promyelocytic leukemia or high-risk neuroblastoma. However, the formation of resistant cells, which results from dysregulation of different signaling pathways, limits therapy success. The present study aimed to characterize basic regulatory processes induced by the application of RA in human neuroblastoma cells, to identify therapeutic targets independent of the often amplified oncogene MYCN. MATERIALS AND METHODS: In MYCN-amplified Kelly and MYCN non-amplified SH-SY5Y cells, different assays were employed to quantify the viability and cytotoxicity, while RA-mediated expression changes were examined using genome-wide gene expression analysis followed by quantitative PCR. Enzyme-linked immunoabsorbent assays (ELISA) and western blots were used to determine the levels or activation of the examined proteins. RESULTS: In Kelly cells, treatment with 5 µM RA for 3 days significantly reduced the cell number due to attenuated proliferation, while SH-SY5Y cells were less responsive. An up-regulation of the RA-metabolizing enzymes CYP26A1 and CYP26B1 was observed in both cell lines, and co-treatment with the selective CYP26 inhibitor talarozole markedly decreased cell viability. When RA and ketoconazole, which inhibits CYP26 as well as RA-degrading CYP3A enzymes, were co-administered, not only cell survival was impaired in both cell lines, but also the release of hepatocyte growth factor (HGF). Accordingly, co-application of the c-Met inhibitor tepotinib and RA or ketoconazole substantially decreased cell viability. CONCLUSION: Independent of MYCN amplification, inhibitors of RA metabolism or HGF signaling might prevent the emergence of RA-resistant neuroblastoma cells when co-applied with RA.

Deletion of PMP3 increases ketoconazole resistance by affecting plasma membrane potential in Candida albicans.

Ketoconazole is a classical antifungal drug commonly used in the clinic. With the increased use of ketoconazole in recent years, an increasing number of drug-resistant strains have emerged during clinical treatment. It is well known that fungi acquire drug resistance in multiple ways, while the molecular mechanisms underlying ketoconazole resistance remain for comprehensive exploration. In this study, we found that the expression of the small plasma membrane protein-encoding gene PMP3 was significantly down-regulated in several clinically isolated ketoconazole-resistant strains, indicating the relationship between PMP3 expression and ketoconazole resistance. By knocking out the PMP3, we found that the absence of the Pmp3 resulted in a significant increase in resistance of Candida albicans to ketoconazole, which was also confirmed in a systemic infection model in mice. We further demonstrated that various physiological properties, such as cell membrane fluidity, plasma membrane potential, permeability and ergosterol distribution were altered in the pmp3Δ/Δ mutant, which is associated with the enhanced cellular resistance to ketoconazole. In addition, overexpression rather than deletion of PMP3 alters the hyphal development and biofilm formation capacity in C. albicans. This study reveals the contribution of Pmp3 to alteration of drug resistance in fungal pathogens, which may guide the development of novel antifungal strategies.

HSPiP and QbD oriented optimized stearylamine-elastic liposomes for topical delivery of ketoconazole to treat deep seated fungal infections: In vitro and ex vivo evaluations.

The study explored stearylamine containing cationic elastic liposomes to improve topical delivery and efficacy of ketoconazole (KETO) to treat deeply seated fungal infections. Stearylamine was used for dual functionalities (electrostatic interaction and flexibility in lipid bilayer). Hansen solubility program (HSPiP) estimated Hansen solubility parameters (HSP) based on the SMILE file and structural properties followed by experimental solubility study to validate the predicted values. Various formulations were developed by varying phosphatidylcholine and surfactants (tween 80 and span 80) concentration. To impart cationic properties, stearylamine (1.0 %) was added into the organic phase. Using quality by design (QbD) method, we optimized the formulations and evaluated for vesicle size, polydispersity index, zeta potential, morphology (scanning electron microscopy), in vitro drug release (%), and ex vivo permeation profiles. Result showed that there is a good correlation (0.65) between HSPiP predicted and actual experimental solubility of KETO in water, chloroform, S80, and tween 80. Spherical OKEL1 showed an established correlation between the predicted and the actual formulation parameters (size, zeta potential, and polydispersity index) (259 nm vs 270 nm, +2.4 vs 0.21 mV, and 0.24 vs 0.27). OKEL1 was associated with the highest value of %EE (83.1 %) as compared to liposomes. Finally, OKEL1 exhibited the highest % cumulative permeation (49.9 %) as compared to DS (13 %) and liposomes (25 %). Moreover, OKEL1 resulted in 4-fold increase in permeation flux as compared to DS which may be attributed to vesicular mediated improved permeation and gel based compensated trans epidermal water loss in the skin. The drug deposition elicited OKEL1 and OKEL1-gel as suitable carriers for maximum therapeutic benefit to treat deeply seated fungal infections.

Reactive oxygen species sensitive nanomicelles promote the antifungal activity of ketoconazole against Candida albicans in vulvovaginal candidiasis.

Excessive local accumulation of reactive oxygen species (ROS) in vulvovaginal candidiasis (VVC) leads to oxidative stress and aggravates inflammation. This study aimed to optimize and synthesize four ROS-sensitive polyethylene glycol (PEG)-boride polymers (PB, PCB, BPB, and BCPCB). A nanomicelle (BCPCB-K) was constructed using BCPCB-encapsulated ketoconazole (KTZ). Finally, the depolymerization principle and ROS-sensitive drug release of BCPCB-K as well as its anti-Candida albicans (CA) and therapeutic effects on mice with VVC were explored through in vitro and in vivo experiments. BCPCB-K exhibited low toxicity to mammalian cells in vitro and good biocompatibility in vivo. It also improved the dispersion and solubility of the hydrophobic drug KTZ. Furthermore, BCPCB-K simultaneously scavenged ROS and released the drug, thus facilitating the antifungal and VVC-treating effects of KTZ. Overall, the findings of this study broadened the application of ROS-sensitive materials in the drug-loading and antifungal fields and provided a strategy for VVC treatment.

Ketoconazole induces reversible antifungal drug tolerance mediated by trisomy of chromosome R in Candida albicans.

Background: The emergence of tolerance to antifungal agents in Candida albicans complicates the treatment of fungal infections. Understanding the mechanisms underlying this tolerance is crucial for developing effective therapeutic strategies. Objective: This study aims to elucidate the genetic and molecular basis of ketoconazole tolerance in C. albicans, focusing on the roles of chromosomal aneuploidy, Hsp90, and calcineurin. Methods: The wild-type C. albicans strain SC5314 was exposed to increasing concentrations of ketoconazole (0.015-32 µg/mL) to select for tolerant adaptors. Disk diffusion and spot assays were used to assess tolerance. Whole-genome sequencing identified chromosomal changes in the adaptors. The roles of Hsp90 and calcineurin in maintaining and developing ketoconazole tolerance were investigated using specific inhibitors and knockout strains. Results: Adaptors exhibited tolerance to ketoconazole concentrations up to 16 µg/mL, a significant increase from the parent strain's inhibition at 0.015 µg/mL. All tolerant adaptors showed amplification of chromosome R, with 29 adaptors having trisomy and one having tetrasomy. This aneuploidy was unstable, reverting to euploidy and losing tolerance in drug-free conditions. Both Hsp90 and calcineurin were essential for maintaining and developing ketoconazole tolerance. Inhibition of these proteins resulted in loss of tolerance. The efflux gene CDR1 was not required for the development of tolerance. Chromosome R trisomy and tetrasomy induce cross-tolerance to other azole antifungal agents, including clotrimazole and miconazole, but not to other antifungal classes, such as echinocandins and pyrimidines, exemplified by caspofungin and 5-flucytosine. Conclusion: Ketoconazole tolerance in C. albicans is mediated by chromosomal aneuploidy, specifically chromosome R amplification, and requires Hsp90 and calcineurin. These findings highlight potential targets for therapeutic intervention to combat antifungal tolerance and improve treatment outcomes.

White piedra on pediatric scalp: A case report.

This case report describes a rare fungal infection, piedra alba, in a 5-year-old female initially misdiagnosed. Treatment with 2 % ketoconazole shampoo led to significant regression within a week, without the need for hair cutting. We discuss the importance of early and accurate diagnosis, highlighting potential hair damage and complications in immunocompromised cases. Dermatoscopy aided diagnosis, and 2 % ketoconazole demonstrated efficacy, emphasizing the need for a multidisciplinary approach and dermatological follow-up.

In vitro effects of N-acetylcysteine in combination with antifungal agents against Malassezia pachydermatis isolated from canine otitis externa.

BACKGROUND: Many clinicians prescribe antifungal agents to treat canine otitis externa (OE). However, studies evaluating the antifungal effects of N-acetylcysteine (NAC) and its combinations are limited. HYPOTHESIS/OBJECTIVES: The aim of this study was to evaluate the antifungal effects of NAC alone and in combination with other antifungal agents against Malassezia pachydermatis isolated from canine OE. MATERIALS AND METHODS: M. pachydermatis samples were collected from 13 dogs with OE. The final concentration of the inoculum suspensions of M. pachydermatis was 1-5 × 106 colony forming units/mL. The concentrations of the test compounds ketoconazole (KTZ), terbinafine (TER), nystatin (NYS) and NAC were 0.02-300 µg/mL, 0.04-80 µg/mL, 0.16-40 µg/mL and 1.25-20 mg/mL, respectively. The minimum inhibitory concentration (MIC) was measured to evaluate the susceptibility of the M. pachydermatis to KTZ, TER, NYS and NAC. The checkerboard testing method and fractional inhibitory concentration index were used to evaluate the effect of NAC in combination with KTZ, TER and NYS against M. pachydermatis. RESULTS: The MIC90 values of M. pachydermatis were 4.6875-9.375 µg/mL, 1.25 µg/mL, 5-10 µg/mL and 10 mg/mL for KTZ, TER, NYS and NAC, respectively. The synergistic effects of KTZ, TER and NYS with NAC were identified in 0/13, 2/13 and 0/13 isolates, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: NAC had an antifungal effect against M. pachydermatis but did not exert synergistic effects when used with KTZ, TER and NYS. Thus, the use of NAC alone as a topical solution could be considered an effective treatment option for canine OE involving M. pachydermatis.

Supramolecular architectures in multicomponent crystals of imidazole-based drugs and trithiocyanuric acid.

The structures of three multicomponent crystals formed with imidazole-based drugs, namely metronidazole, ketoconazole and miconazole, in conjunction with trithiocyanuric acid are characterized. Each of the obtained adducts represents a different category of crystalline molecular forms: a cocrystal, a salt and a cocrystal of salt. The structural analysis revealed that in all cases, the N-H...N hydrogen bond is responsible for the formation of acid-base pairs, regardless of whether proton transfer occurs or not, and these molecular pairs are combined to form unique supramolecular motifs by centrosymmetric N-H...S interactions between acid molecules. The complex intermolecular forces acting in characteristic patterns are discussed from the geometric and energetic perspectives, involving Hirshfeld surface analysis, pairwise energy estimation, and natural bond orbital calculations.

Ketoconazole blocks progesterone production without affecting other parameters of cumulus-oocyte complex maturation.

Ketoconazole (KTZ) is widely used as a fungicide, but it is also known to target steroid hormone formation which may affect female reproductive health. Our study aims to investigate the effects of KTZ on in vitro matured bovine cumulus-oocyte complexes (COCs), as a model for female reproductive toxicity. Cumulus cells of in vitro maturing COCs produce progesterone and pregnenolone, but exposure to 10-6 M KTZ effectively blocked the synthesis of these hormones. Exposure to lower concentrations of KTZ (i.e. 10-7 M and 10-8 M) had no such effect on steroidogenesis compared to the 0.1 % v/v DMSO vehicle control. Classical parameters of in vitro COC maturation, such as oocyte nuclear maturation to the metaphase II stage and expansion of the cumulus investment, were not affected by any KTZ concentration tested. Apoptosis and necrosis levels were also not altered in cumulus cells or oocytes exposed to KTZ. Moreover, oocytes exposed to KTZ during maturation showed normal cleavage and early embryo development up to day 8 post fertilization; albeit a statistically significant decrease was observed in day 8 blastocysts produced from oocytes exposed to the lowest concentration of 10-8 M KTZ. When unexposed mature oocytes were fertilized, followed by embryo culture for 8 days under KTZ exposure, no adverse effects in embryo cleavage and blastocyst formation were observed. In conclusion, KTZ has no major impact on in vitro bovine oocyte maturation and blastocyst formation in our study, even at concentrations blocking steroidogenesis.

Management of androgenic alopecia: a systematic review of the literature.

We aimed to determine the efficacy of the various available oral, topical, and procedural treatment options for hair loss in individuals with androgenic alopecia. Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, a systematic review of the National Library of Medicine was performed. Overall, 141 unique studies met our inclusion criteria. We demonstrate that many over the counter (e.g. topical minoxidil, supplements, low-level light treatment), prescription (e.g. oral minoxidil, finasteride, dutasteride), and procedural (e.g. platelet-rich plasma, fractionated lasers, hair transplantation) treatments successfully promote hair growth, highlighting the superiority of a multifaceted and individualized approach to management.

Bisphosphonates synergistically enhance the antifungal activity of azoles in dermatophytes and other pathogenic molds.

Superficial infections of the skin, hair, and nails by fungal dermatophytes are the most prevalent of human mycoses, and many infections are refractory to treatment. As current treatment options are limited, recent research has explored drug synergy with azoles for dermatophytoses. Bisphosphonates, which are approved to treat osteoporosis, can synergistically enhance the activity of azoles in diverse yeast pathogens but their activity has not been explored in dermatophytes or other molds. Market bisphosphonates risedronate, alendronate, and zoledronate (ZOL) were evaluated for antifungal efficacy and synergy with three azole antifungals: fluconazole (FLC), itraconazole (ITR), and ketoconazole (KET). ZOL was the most active bisphosphonate tested, displaying moderate activity against nine dermatophyte species (MIC range 64-256 µg/mL), and was synergistic with KET in eight of these species. ZOL was also able to synergistically improve the anti-biofilm activity of KET and combining KET and ZOL prevented the development of antifungal resistance. Rescue assays in Trichophyton rubrum revealed that the inhibitory effects of ZOL alone and in combination with KET were due to the inhibition of squalene synthesis. Fluorescence microscopy using membrane- and ROS-sensitive probes demonstrated that ZOL and KET:ZOL compromised membrane structure and induced oxidative stress. Antifungal activity and synergy between bisphosphonates and azoles were also observed in other clinically relevant molds, including species of Aspergillus and Mucor. These findings indicate that repurposing bisphosphonates as antifungals is a promising strategy for revitalising certain azoles as topical antifungals, and that this combination could be fast-tracked for investigation in clinical trials. IMPORTANCE: Fungal infections of the skin, hair, and nails, generally grouped together as "tineas" are the most prevalent infectious diseases globally. These infections, caused by fungal species known as dermatophytes, are generally superficial, but can in some cases become aggressive. They are also notoriously difficult to resolve, with few effective treatments and rising levels of drug resistance. Here, we report a potential new treatment that combines azole antifungals with bisphosphonates. Bisphosphonates are approved for the treatment of low bone density diseases, and in fungi they inhibit the biosynthesis of the cell membrane, which is also the target of azoles. Combinations were synergistic across the dermatophyte species and prevented the development of resistance. We extended the study to molds that cause invasive disease, finding synergy in some problematic species. We suggest bisphosphonates could be repurposed as synergents for tinea treatment, and that this combination could be fast-tracked for use in clinical therapy.

Xanthan-Polyurethane Conjugates: An Efficient Approach for Drug Delivery.

The antifungal agent, ketoconazole, and the anti-inflammatory drug, piroxicam, were incorporated into matrices of xanthan or oleic acid-esterified xanthan (Xn) and polyurethane (PU), to develop topical drug delivery systems. Compared to matrices without bioactive compounds, which only showed a nominal compressive stress of 32.18 kPa (sample xanthan-polyurethane) at a strain of 71.26%, the compressive resilience of the biomaterials increased to nearly 50.04 kPa (sample xanthan-polyurethane-ketoconazole) at a strain of 71.34%. The compressive strength decreased to around 30.67 kPa upon encapsulating a second drug within the xanthan-polyurethane framework (sample xanthan-polyurethane-piroxicam/ketoconazole), while the peak sustainable strain increased to 87.21%. The Weibull model provided the most suitable fit for the drug release kinetics. Unlike the materials based on xanthan-polyurethane, those made with oleic acid-esterified xanthan-polyurethane released the active ingredients more slowly (the release rate constant showed lower values). All the materials demonstrated antimicrobial effectiveness. Furthermore, a higher volume of piroxicam was released from oleic acid-esterified xanthan-polyurethane-piroxicam (64%) as compared to xanthan-polyurethane-piroxicam (44%). Considering these results, materials that include polyurethane and either modified or unmodified xanthan showed promise as topical drug delivery systems for releasing piroxicam and ketoconazole.

Randomly Methylated ß-Cyclodextrin Inclusion Complex with Ketoconazole: Preparation, Characterization, and Improvement of Pharmacological Profiles.

As a powerful imidazole antifungal drug, ketoconazole's low solubility (0.017 mg/mL), together with its odor and irritation, limited its clinical applications. The inclusion complex of ketoconazole with randomly methylated ß-cyclodextrin was prepared by using an aqueous solution method after cyclodextrin selection through phase solubility studies, complexation methods, and condition selection through single factor and orthogonal strategies. The complex was confirmed by FTIR (Fourier-transform infrared spectroscopy), DSC (differential scanning calorimetry), TGA (thermogravimetric analysis), SEM (scanning electron microscope images), and NMR (Nuclear magnetic resonance) studies. Through complexation, the water solubility of ketoconazole in the complex was increased 17,000 times compared with that of ketoconazole alone, which is the best result so far for the ketoconazole water solubility study. In in vitro pharmacokinetic studies, ketoconazole in the complex can be 100% released in 75 min, and in in vivo pharmacokinetic studies in dogs, through the complexation, the Cmax was increased from 7.56 µg/mL to 13.58 µg/mL, and the AUC0~72 was increased from 22.69 µgh/mL to 50.19 µgh/mL, indicating that this ketoconazole complex can be used as a more efficient potential new anti-fungal drug.

Effects of Clarithromycin and Ketoconazole on FK506 Metabolism in Different CYP3A4 Genotype Recombinant Metabolic Enzyme Systems.

OBJECTIVE: This study aimed to investigate the effects of clarithromycin and ketoconazole on the pharmacokinetic properties of tacrolimus in different CYP3A4 genotype recombinant metabolic enzyme systems, so as to understand the drug interactions and their mechanisms further. METHOD: The experiment was divided into three groups: a blank control group, CYP3A4*1 group and CYP3A4*18 recombinant enzyme group. Each group was added with tacrolimus (FK506) of a series of concentrations. Then 1 umol/L clarithromycin or ketoconazole was added to the recombinant enzyme group and incubated in the NADPH system for 30 minutes to examine the effects of clarithromycin and ketoconazole on the metabolizing enzymes' activity of different genotypes. The remaining concentration of FK506 in the reaction system was determined using UPLC-MS/MS, and the enzyme kinetic parameters were calculated using the software. RESULTS: The metabolism of CYP3A4*18 to FK506 was greater than that of CyP3А4*1B. Compared with the CYP3A4*1 group, the metabolic rate and clearance of FK506 in the CYP3A4*18 group significantly increased, with Km decreasing. Clarithromycin and ketoconazole inhibit the metabolism of FK506 by affecting the enzyme activity of CYP3A4*1B and CYP3A4*18B. After adding clarithromycin or ketoconazole, the metabolic rate of FK506 significantly decreased in CYP3A4*1 and CYP3A4*18, with Km increasing, Vmax and Clint decreasing. CONCLUSION: Compared with CYP3A4*1, CYP3A4*18 has a greater metabolism of FK506, clarithromycin and ketoconazole can inhibit both the enzymatic activities of CYP3A4*1 and CYP3A4*18, consequently affecting the metabolism of FK506 and the inhibitory on CYP3A4*1 is stronger.