Comparison of solid self-microemulsifying drug delivery system (solid SMEDDS) prepared with hydrophilic and hydrophobic solid carrier

In order to compare the effects of hydrophilic and hydrophobic solid carrier on the formation of solid self-microemulsifying drug delivery system (SMEDDS), two solid SMEDDS formulations were prepared by spray-drying the solutions containing liquid SMEDDS and solid carriers. Colloidal silica and dextran were used as a hydrophobic and a hydrophilic carrier, respectively. The liquid SMEDDS, composed of Labrafil M 1944 CS/Labrasol/Trasncutol HP (12.5/80/7.5%) with 2% w/v flurbiprofen, gave a z-average diameter of about 100 nm. Colloidal silica produced an excellent conventional solid SMEDDS in which the liquid SMEDDS was absorbed onto its surfaces. It gave a microemulsion droplet size similar to that of the liquid SMEDDS (about 100 nm) which was smaller than the other solid SMEDDS formulation. In the solid SMEDDS prepared with dextran, liquid SMEDDS was not absorbed onto the surfaces of carrier but formed a kind of nano-sized microcapsule with carrier. However, the drug was in an amorphous state in two solid SMEDDS formulations. Similarly, they greatly improved the dissolution rate and oral bioavailability of flurbiprofen in rats due to the fast spontaneous emulsion formation and the decreased droplet size. Thus, except appearance, hydrophilic carrier (dextran) and hydrophobic carrier (colloidal silica) hardly affected the formation of solid SMEDDS such as crystalline properties, dissolution and oral bioavailability.     

Physicochemical characterization and in vivo evaluation of flurbiprofen-loaded solid dispersion without crystalline change

To develop a novel flurbiprofen-loaded solid dispersion without crystalline change, various flurbiprofen-loaded solid dispersions were prepared with water, sodium carboxylmethyl cellulose (Na-CMC), and Tween 80. The effect of Na-CMC and Tween 80 on aqueous solubility of flurbiprofen was investigated. The physicochemical properties of solid dispersions were investigated using SEM, DSC, and X-ray diffraction. The dissolution and bioavailability in rats were evaluated compared to commercial product. Unlike conventional solid dispersion systems, the flurbiprofen-loaded solid dispersion gave a relatively rough surface and changed no crystalline form of drug. These solid dispersions were formed by attaching hydrophilic carriers to the surface of drug without crystal change, resulting in changing the hydrophobic drug to hydrophilic form. Furthermore, the flurbiprofen-loaded solid dispersion at the weight ratio of flurbiprofen/Na-CMC/Tween 80 of 6/2.5/0.5 improved ～ 60-fold drug solubility. It gave higher AUC, T_max, and C_max compared to commercial product. The solid dispersion improved almost 1.5-fold bioavailability of drug compared to commercial product in rats. Thus, the flurbiprofen-loaded solid dispersion would be useful to deliver poorly water-soluble flurbiprofen with enhanced bioavailability without crystalline change.     

Solid self-nanoemulsifying drug delivery system (SNEDDS) for enhanced oral bioavailability of poorly water-soluble tacrolimus: physicochemical characterisation and pharmacokinetics

Abstract

To develop a novel self-nanoemulsifying drug delivery system (solid SNEDDS) with better oral bioavailability of tacrolimus, the solid SNEDDS was obtained by spray-drying the solutions containing the liquid SNEDDS and colloidal silica. Its reconstitution properties were determined and correlated to solid state characterisation of the powder. Moreover, the dissolution and pharmacokinetics in rats was done in comparison to the commercial product. Among the liquid SNEDDS formulations tested, the liquid SNEDDS comprised of Capryol PGMC, Transcutol HP and Labrasol (10:15:75, v/v/v) presented the highest dissolution rate. In the solid SNEDDS, this liquid SNEDDS was absorbed in the pores and attached onto the surface of the colloidal silica. Drug was present in the amorphous state in it. The solid SNEDDS with 5% w/v tacrolimus produced the nanoemulsions and improved the oral bioavailability of tacrolimus in rats. Therefore, this solid SNEDDS would be a potential candidate for enhancing the oral bioavailability of tacrolimus.     

Enhancement of solubility and permeability of Candesartan cilexetil by using different pharmaceutical interventions

The poor solubility and wettability of Candesartan cilexetil (CAN) leads to poor dissolution and hence, low bioavailability after oral administration. The aim of the present study was to improve the solubility and dissolution rate and hence the permeability of CAN by preparing solid dispersions/inclusion complexes. Solid dispersions were prepared using PEG 6000 [hydrophilic polymer] and Gelucire 50/13 [amphiphilic surfactant] by melt agglomeration (MA) and solvent evaporation (SE) methods in different drug-to-carrier ratios, while inclusion complexes were made with hydroxypropyl-β-cyclodextrin (HP-β-CD) [complexing agent] by grinding and spray drying method. Saturation solubility method was used to evaluate the effect of various carriers on aqueous solubility of CAN. Based on the saturation solubility data, two drug-carrier combinations, PEG 6000 (MA 1:5) and HP-β-CD (1:1 M grinding) were selected as optimized formulations. FTIR, DSC, and XRD studies indicated no interaction of the drug with the carriers and provided valuable insight on the possible reasons for enhanced solubility. Dissolution studies showed an increase in drug dissolution of about 22 fold over the pure drug for PEG 6000 (MA 1:5) and 12 fold for HP-β-CD (1:1 M grinding). Ex-vivo permeability studies revealed that the formulation having the greatest dissolution also had the best absorption through the chick ileum. Capsules containing solid dispersion/ complex exhibited better dissolution profile than the marketed product. Thus, the solid dispersion/inclusion complexation technique can be successfully used for enhancement of solubility and permeability of CAN.     

Physicochemical characterization and in vivo evaluation of solid self-nanoemulsifying drug delivery system for oral administration of docetaxel

To formulate a self-nanoemulsifying drug delivery system (SNEDDS) for the oral administration of docetaxel as an alternative to commercial docetaxel-loaded injectable products, it was prepared by spray-drying an aqueous solution containing liquid SNEDDS and colloidal silica. Its physicochemical properties and oral bioavailability were investigated compared to a clear docetaxel solution administered intravenously or orally to rats. In the docetaxel-loaded solid SNEDDS prepared with colloidal silica, the liquid SNEDDS composed of Capryol 90, Cremophore EL and Transcutol HP (45/35/20, volume ratio) was absorbed inside the pores of carriers, and docetaxel was present in a changed amorphous state. The solid SNEDDS with 3.3% (w/v) docetaxel produced nanoemulsions, and showed about 12.5% absolute bioavailability in rats. Thus, this solid SNEDDS may be a potential candidate for oral pharmaceutical product with improved oral bioavailability of docetaxel.     

Development of novel flurbiprofen-loaded solid self-microemulsifying drug delivery system using gelatin as solid carrier

To develop a novel flurbiprofen-loaded solid self-microemulsifying drug delivery system (solid SMEDDS) with improved oral bioavailability using gelatin as a solid carrier, the solid SMEDDS formulation was prepared by spray-drying the solutions containing liquid SMEDDS and gelatin. The liquid SMEDDS, composed of Labrafil M 1944 CS/Labrasol/Transcutol HP (12.5/80/7.5%) with 2% w/v flurbiprofen, gave a z-average diameter of about 100?nm. The flurbiprofen-loaded solid SMEDDS formulation gave a larger emulsion droplet size compared to liquid SMEDDS. Unlike conventional solid SMEDDS, it produced a kind of microcapsule in which liquid SMEDDS was not absorbed onto the surfaces of carrier but formed together with carrier in it. However, the drug was in an amorphous state in it like conventional solid SMEDDS. It greatly improved the oral bioavailability of flurbiprofen in rats. Thus, gelatin could be used as a carrier in the development of solid SMEDDS with improved oral bioavailability of poorly water-soluble drug.     

Solid super saturated self-nanoemulsifying drug delivery system (sat-SNEDDS) as a promising alternative to conventional SNEDDS for improvement rosuvastatin calcium oral bioavailability

ABSTRACT

Objective: This study aims to illustrate the applicability of solid supersaturated self-nanoemulsifying drug delivery system (sat-SNEDDS) for the improvement of rosuvastatin calcium (RC) oral bioavailability.

Methods: Different sat-SNEDDS were prepared by incorporating different ratios of RC into SNEDDS using tween80/PEG400 (77.2%) as surfactant/cosurfactant mixture and garlic /olive oil (22.8%) as oil phase. The prepared systems were characterized viz; size, zeta potential, TEM and stability. Various hydrophilic and hydrophobic carriers were employed to solidify the optimized RC sat-SNEDDS. The influence of the carrier was investigated by SEM, XRPD, DSC, flow properties, in vitro precipitation, drug release and oral bioavailability study.

Results: The adsorption of the stable positively charged nanocarrier RC sat-SNEDDS onto solid carriers provided free flowing amorphous powder. The carrier could amend the morphological architecture and in vitro release of the RC solid sat-SNEDDS. Hydrophobic carriers as microcrystalline cellulose 102 (MCC) showed superior physical characters and higher dissolution rate over hydrophilic carriers as maltodextrin with respective T_100% 30 min and 45 min. The rapid spontaneous emulsification, the positively nanosized MCC-sat-SNEDDS improved oral bioavailability of RC by 2.1-fold over commercial tablets.

Conclusion: Solid MCC-sat-SNEDDS combined dual benefits of sat-SNEDDS and solid dosage form was successfully optimized to improve RC oral bioavailability.     

In vitro and in vivo evaluation of novel immediate release carbamazepine tablets: complexation with hydroxypropyl-β-cyclodextrin in the presence of HPMC

Carbamazepine (CBZ)-hydroxypropyl-β-cyclodextrin (HP-β-CD) complex in the presence of HPMC was prepared and characterized by differential scanning calorimetry (DSC) and X-ray diffractometer intended for improving the dissolution rate of CBZ. The phase-solubility method was used to investigate the effect of HP-β-CD and HPMC on the solubility of CBZ. Tablets of the resulting complex were prepared using direct compression method and the bioavailability was evaluated in beagle dogs using a UPLC/MS/MS method. The results showed solubility of CBZ was increased up to 95 times by complexation with HP-β-CD in the presence of 0.1% HPMC. The results of DSC and X-ray diffraction proved a formation of complex between CBZ and HP-β-CD. Dissolution rate of CBZ was notably improved from complex tablets with more than 97.39% released within 10 min; whereas for the commercial tablets, around 60% was released within 30 min. Using commercial tablets as the reference formulation, the bioavailability of complex tablets was considerably increased by 1.5-fold (P<0.05) and T(max) was reduced to 0.88 h compared with 1.25 h for commercial tablets. Furthermore, a lower inter-subject variability (49.9%) was observed compared with that of the commercial tablets (39.7%). It is evident from the results herein that complexation with HP-β-CD in the presence of HPMC is a feasible way to prepare a rapidly acting and better absorbed CBZ oral product.     

Novel oral dosage regimen based on self-nanoemulsifying drug delivery systems for codelivery of phytochemicals – Curcumin and thymoquinone

BackgroundCurcumin and Thymoquinone are very well-known phytochemicals for their potent anti-inflammatory and anticancer properties. The major challenges for curcumin is its poor aqueous solubility and erratic oral bioavailability.ObjectiveTo develop a novel liquid self-nanoemulsifying drug delivery system (SNEDDS) containing curcumin and thymoquinone and further converted into a solid dosage form using adsorbents Syloid® and Neusilin® as the solid carrier.MethodsThe characterization of the liquid and solid SNEDDS was performed by particle size & zeta potential analysis, scanning electron microscopy, differential scanning calorimetry, fourier transform infrared spectroscopy and X-ray powder diffraction. The drug loading, and in vitro release studies were carried out to investigate the efficiency of curcumin release from SNEDDS.ResultsThe liquid SNEDDS containing black seed oil showed excellent self-emulsification performance with transparent appearance. The results of characterization studies showed that solidification using 50% (w/w) Syloid® and Neusilin® in the liquid formulation yield free flowing powder with no agglomeration but Neusilin® produced smooth granules than Syloid® and kept the drugs stable in amorphous state. In vitro dissolution studies indicated that liquid SNEDDS formulations of F4 and its solid SNEDDS using Neusilin® provided high dissolution efficiency and reproducibility for curcumin and thymoquinone. However, Neusilin® showed higher rate of dissolution (more than 65%, p < 0.05) compared to Syloid® for curcumin.ConclusionsCurcumin loaded-SNEDDS formulation containing thymoquinone in liquid & solid dosage forms were successfully developed with an increased drug loading and dissolution rate, which could be the potential combined delivery system for various anti-inflammatory and anti-cancer treatments.     

Surface-adsorbed reverse micelle-loaded solid self-nanoemulsifying drug delivery system of talinolol

The aim of present investigation was to develop surface-adsorbed reverse-micelle-loaded solid self-nanoemulsifying drug delivery system (SNEDDS) of talinolol in order to enhance its in vitro dissolution rate, which in turn enhance the bioavailability. SNEDDS were prepared using aqueous phase titration method. Thermodynamically stable formulations were characterized in terms of droplet size, viscosity, % transmittance, drug content and surface morphology. Low cost acid-treated coffee husk was used as an effective biosorbent for preparation of solid SNEDDS. Developed SNEDDS were subjected to in vitro drug release/dissolution studies. In vitro drug release studies showed 99.6% release of talinolol from optimized solid SNEDDS TS3 after 120?min of study. The results of solubility studies showed 4849.5-folds enhancement in solubility of talinolol from optimized SNEDDS as compared to its aqueous solubility.     

Cyclodextrin-water soluble polymer ternary complexes enhance the solubility and dissolution behaviour of poorly soluble drugs. Case example: Itraconazole

The aim of the present series of experiments was to improve the solubility and dissolution/precipitation behaviour of a poorly soluble, weakly basic drug, using itraconazole as a case example. Binary inclusion complexes of itraconazole with two commonly used cyclodextrin derivatives and a recently introduced cyclodextrin derivative were prepared. Their solubility and dissolution behaviour was compared with that of the pure drug and the marketed formulation Sporanox®. Ternary complexes were prepared by addition of Soluplus®, a new highly water soluble polymer, during the formation of the itraconazole/cyclodextrin complex. A solid dispersion made of itraconazole and Soluplus® was also studied as a control. Solid state analysis was performed for all formulations and for pure itraconazole using powder X-ray diffraction (pX-RD) and differential scanning calorimetry (DSC). Solubility tests indicated that with all formulation approaches, the aqueous solubility of itraconazole formed with hydroxypropyl-β-cyclodextrin (HP-β-CD) or hydroxybutenyl-β-cyclodextrin (HBen-β-CD) and Soluplus® proved to be the most favourable formulation approaches. Whereas the marketed formulation and the pure drug showed very poor dissolution, both of these ternary inclusion complexes resulted in fast and extensive release of itraconazole in all test media. Using the results of the dissolution experiments, a newly developed physiologically based pharmacokinetic (PBPK) in silico model was applied to compare the in vivo behaviour of Sporanox® with the predicted performance of the most promising ternary complexes from the in vitro studies. The PBPK modelling predicted that the bioavailability of itraconazole is likely to be increased after oral administration of ternary complex formulations, especially when itraconazole is formulated as a ternary complex comprising HP-β-CD or HBen-β-CD and Soluplus®.     

羟丙基-β-环糊精对兰索拉唑的增溶作用及其包合物的制备

目的研究羟丙基-β-环糊精(HP--βCD)对难溶性药物兰索拉唑(LPZ)的包合作用。方法绘制相溶解度图,考察pH变化、碳酸氢钠的加入对LPZ的增溶作用。采用共蒸发法(CE)和喷雾干燥法(SD)按照LPZ∶HP--βCD量比为1∶1或1.0∶1.5的比例制备LPZ/HP--βCD包合物,测定其溶出度,并利用差示扫描量热法(DSC)和傅立叶红外光谱法(FTIR)对SD法制备的包合物进行结构表征。结果在pH 11条件下,HP-β-CD与NaHCO3对LPZ的协同增溶效果最好。体外溶出实验表明:CE法和SD法制备的包合物溶出均优于LPZ与HP-β-CD的物理混合物。结论HP--βCD能明显提高LPZ的溶解度和溶出度。     

Stabilization of the Metastable α–Form of Indomethacin Induced by the Addition of 2-Hydroxypropyl-β-Cyclodextrin,Causing Supersaturation (Spring) and Its Sustaining Deployment (Parachute)

The purpose of this study is to find that a small amount of 2-Hydroxypropyl-β-cyclodextrin (HP-β-CD) can produce a parachute effect on indomethacin (INM). From the examination of dissolution curves and concentration after several days, the supersaturation of INM was observed for the mixtures containing HP-β-CD at a molar ratio ≤ 0.5, and the sustained deployment of supersaturation was found not only in equimolar mixtures but also in mixtures with a shortage of HP-β-CD. In the solid state, it was compared the physical properties of INM/HP-β-CD mixtures using two different mixing methods and determined the stoichiometry of INM and HP-β-CD. Differential scanning calorimetry (DSC) revealed that the polymorphs of INM were converted by HP-β-CD into an amorphous state. Furthermore, X-ray powder diffraction (XRPD) and DSC–XRPD demonstrated that INM crystals from the INM/HP-β-CD mixture prepared from an EtOH solution were metastable. In conclusion, these phenomena may be considered the "spring" and "parachute" effects of mixtures with a shortage of HP-β-CD, as they depended on the presence of the metastable α-form of INM. The addition of 1/3 to 1/20 equivalents of HP-β-CD to INM enhanced INM solubility.     

The characterization and dissolution performances of spray dried solid dispersion of ketoprofen in hydrophilic carriers

Solid dispersion is one of the most promising strategies to improve oral bioavailability of poorly soluble API. However, there are inconsistent dissolution performances of solid dispersion reported which entails further investigation. In this study, solid dispersions of ketoprofen in three hydrophilic carriers, i.e. PVP K30, PVPVA 6:4 and PVA were prepared and characterized. Physical characterization of the physical mixture of ketoprofen and carriers shows certain extent of amorphization of the API. This result is coinciding to evaluation of drug–polymer interaction using ATR-FTIR whereby higher amorphization was seen in samples with higher drug–polymer interaction. XRPD scanning confirms that fully amorphous solid dispersion was obtained for SD KTP PVP K30 and PVPVA system whereas partially crystalline system was obtained for SD KTP PVA. Interestingly, dissolution profiles of the solid dispersion had shown that degree of amorphization of KTP was not directly proportional to the dissolution rate enhancement of the solid dispersion system. Thus, it is concluded that complete amorphization does not guarantee dissolution enhancement of an amorphous solid dispersion system.     

Inclusion complexes of tadalafil with natural and chemically modified β-cyclodextrins. I: Preparation and in-vitro evaluation

The aim of this work was to investigate the inclusion complexation between tadalafil, a practically insoluble selective phosphodiesterase-5 inhibitor (PDE5), and two chemically modified β-cyclodextrins: hydroxypropyl-β-cyclodextrin (HP-β-CD) and heptakis-[2,6-di-O-methyl]-β-cyclodextrin (DM-β-CD), in comparison with the natural β-cyclodextrin (β-CD) in order to improve the solubility and the dissolution rate of the drug in an attempt to enhance its bioavailability. Inclusion complexation was investigated in both the solution and the solid state. The UV spectral shift method indicated guest–host complex formation between tadalafil and the three cyclodextrins (CDs). The phase solubility profiles with all the used CDs were classified as A_p-type, indicating the formation of higher order complexes. The complexation efficiency values (CE), which reflect the solubilizing power of the CDs towards the drug, could be arranged in the following order: DM-β-CD > HP-β-CD > β-CD. Solid binary systems of tadalafil with CDs were prepared by kneading and freeze-drying techniques at molar ratios of 1:1, 1:3 and 1:5 (drug to CD). Physical mixtures were prepared in the same molar ratios for comparison. Physicochemical characterization of the prepared systems at molar ratio of 1:5 was studied using differential scanning calorimetry (DSC), X-ray diffractometry (XRD), and Fourier-transform infrared spectroscopy (FTIR). The results showed the formation of true inclusion complexes between the drug and both HP-β-CD and DM-β-CD using the freeze-drying method at molar ratio of 1:5. In contrast, crystalline drug was detectable in all other products. The dissolution of tadalafil from all the prepared binary systems was carried out to determine the most appropriate CD type, molar ratio, and preparation technique to prepare inclusion complexes to be used in the development of tablet formulation for oral delivery of tadalafil. The dissolution enhancement was increased on increasing the CD proportion in all the prepared systems. Both the CD type and the preparation technique played an important role in the performance of the system. Irrespective of the preparation technique, the systems prepared using HP-β-CD and DM-β-CD yielded better performance than the corresponding ones prepared using β-CD. In addition, the freeze-drying technique showed superior dissolution enhancement than other methods especially when combined with the β-CD derivatives.     

Preparation,characterization, dissolution,and permeation of flibanserin − 2-HP-β-cyclodextrin inclusion complexes

Flibanserin (FLB), an antiserotonin drug, is used to treat women with hypoactive sexual appetite disorder. FLB shows low bioavailability (~33%) probably due to its low water solubility. The current study investigated the impact of hydroxypropyl-β-cyclodextrin (HP-β-CD) and sodium lauryl sulfate (SLS) on the dissolution and permeation of FLB. HP-β-CD–FLB inclusion complexes were prepared using physical mixing and kneading at 1:1 and 1:2 M ratios and characterized using differential scanning calorimetry, Fourier transform infrared spectroscopy, and powder X-ray diffractometry. The dissolution and permeation of the complexes through a cellophane membrane were performed in, 0.1, 0.3 and 0.5% SLS in phosphate buffer (pH 6.8).Derived from the slope of the linear phase solubility diagram, the apparent stability constant (K_1:1) was 372.54 M⁻¹. Kneading changed the crystalline form of FLB to an amorphous appearance characterized by minimal crystalline peaks, indicating successful inclusion complex formation. In addition, the HP-β-CD–FLB inclusion complexes showed twofold increased dissolution efficiency at 6 h. The cumulative FLB amount permeated at 6 h increased from 14.1% to 21.88% and 34.56% in the presence of 0.1% and 0.3% of SLS, respectively. However, increasing SLS to 0.5% did not show an increase in FLB permeation. Therefore, the HP-β-CD–FLB inclusion complex has an improved dissolution rate compared to FLB alone. The presence of SLS in the dissolution medium increases the dissolution rate of pure FLB and its complex with HP-β-CD. kneaded 1:1 complex was formulated bioadhesive buccal tablets and showed enhanced drug release.     

西罗莫司-羟丙基-β-环糊精包合物的制备

目的：制备西罗莫司-羟丙基-β-环糊精（HP-β-CD）包合物,并考察HP-β-CD提高西罗莫司溶解度的效果。方法：以西罗莫司与HP-β-CD之比（mol：mol）、包合温度和包合时间为因素,包合率、收得率为指标,采用正交试验筛选西罗莫司-HP-β-CD包合物的制备工艺,并进行溶解度影响、X-射线衍射法结构验证。结果：最佳工艺为：西罗莫司与HP-β-CD之比为1：6（mol：mol）、包合温度为25℃、时间为6h;以此工艺制备3批包合物,平均包合率为25.4%（RSD=1.16%）,平均收得率为86.5%（RSD=0.83%）;随着HP-β-CD浓度增加,西罗莫司溶解度从1.18μg·mL-1增加到49.97μg·mL-1;包合物的晶体衍射峰形几乎与HP-β-CD完全一致。结论：HP-β-CD包合西罗莫司的工艺简单、易操作,能提高西罗莫司的溶解度。     

Development of orally disintegrating tablets of Perphenazine/hydroxypropyl-β-cyclodextrin inclusion complex

The aim of the present work was to prepare perphenazine (PPZ) orally disintegrating tablets (ODTs) based on the use of hydroxypropyl-β-cyclodextrin (HP-β-CD) forming inclusion complex with PPZ to improve the solubility and dissolution of this practically insoluble drug. Phase solubility studies were performed to evaluate the complexation of PPZ with HP-β-CD in three aqueous systems. The inclusion complex prepared by evaporation method was characterized by different physicochemical techniques, including the dissolution studies. The prepared complex was incorporated into ODTs containing different fillers and disintegrants. The ODTs prepared by direct compression were evaluated for drug content, hardness, porosity, friability, in vitro disintegration time (DT), wetting time (WT) and dissolution profiles. The solubility and dissolution rate were substantially improved compared with that of PPZ. Differential scanning calorimetry (DSC), X-ray powder diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR) analyses suggested that PPZ could form true inclusion complex with HP-β-CD. The optimized formulation F6 exhibited short DT (15.5 ± 1.9 s) and WT (34.2 ± 2.3 s), sufficient hardness (30.4 ± 1.6 N/mm) and rapid drug dissolution. The developed tablet formulation could be a promising drug delivery system with improvements in PPZ bioavailability and patient compliance.     

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.