Absorption Of Fenofibrate Research Articles

Formulation of fenofibrate nanocrystals with wet milling method

Background: Fenofibrate is an antihyperlipidemic belonging to BCS class II, practically insoluble in water and has high lipophilicity, so it is proven that the inhibitor of the rate of absorption of fenofibrate from the digestive tract is slow to dissolve. This study aims to increase the solubility of fenofibrate by forming nanocrystals.
 Method: Formation of nanocrystals using the wet milling method
 Result: The fenofibrate nanocrystals produced a particle size of 775.966 nm, a zeta potential of -21.302 mV, and a solubility of 5.977 μg/mL. 
 Conclusion : The optimum formula with tween 80 components, grinding speed and grinding time in the manufacture of fenofibrate nanocrystals using the Factorial Design method obtained 0.2% tween 80, grinding speed of 500 rpm and grinding time of 1 hour. The critical parameter test results for the optimum formula obtained a particle size of 775.966 nm, a zeta potential of -21.302 mV and a solubility of 5.977 µg/mL. The DSC test showed that there was a difference in the melting point peaks and a decrease in crystal intensity between pure fenofibrate and fenofibrate nanocrystals. The FTIR test showed no difference in functional groups between pure fenofibrate and fenofibrate nanocrystals. The XRD test showed that there was a difference in peak crystal intensity between pure fenofibrate and fenofibrate nanocrystals. The SEM analysis shows that there are differences in shape and magnification used between pure fenofibrate and fenofibrate nanocrystals.

Effects of Ingested Water Volume on Oral Absorption of Fenofibrate, a BCS Class II Drug, from Micronized and Amorphous Solid Dispersion Formulations in Rats.

In this study, we investigated the effects of ingested water volume on the oral absorption of fenofibrate (FEN) with several formulations to confirm the applicability of rats for oral formulation screening. Oral absorption of suspended crystalline FEN was significantly improved by increasing ingested water volume (from 0.5 to 2 mL). FEN absorption improvement by particle size reduction and the linearity in oral absorption by dose escalation suggested that the rate-limiting step of FEN absorption in rats was the dissolution rate, consistent with that in humans. When FEN, as an amorphous solid dispersion (ASD) formulation, was suspended in water followed by immediate administration, oral FEN absorption was significantly higher than when administered in crystalline form and was not influenced by the differences in ingested water volume. Oral absorption of FEN from encapsulated ASD formulation in 1 or 2 mL of water was comparable with that of the suspension form. However, 0.5 mL of water significantly reduced the oral absorption of the solid ASD FEN formulation. These results indicate that to improve the oral absorption of poorly water-soluble drugs when performing a preclinical study with rats, 1 mL of water is the minimum preferable ingested volume to evaluate in vivo formulation performance.

Orlistat disposition in the human jejunum and the effect of lipolysis inhibition on bile salt concentrations and composition

The lipolysis-mediated postprandial small intestinal environment is known to influence the solubilisation and subsequent absorption of lipophilic drugs. In a previously performed small-scale clinical study in healthy volunteers, co-administration of the lipase inhibitor orlistat increased jejunal solubilisation and systemic absorption of fenofibrate after intake of the lipid-based formulation Fenogal. In the present study, the jejunal disposition of the locally acting orlistat was assessed and linked to fenofibrate solubilisation. In addition, the effect of orlistat-induced lipolysis inhibition on bile salt concentrations and composition was evaluated. Orlistat was distributed predominantly in the lipid layer, as indicated by a 5- to 14-fold higher AUC0-320 min in the total jejunal samples as compared to the micellar layers. No effect of orally administered orlistat on bile salt composition or total concentrations (ranging from 1.5 to 24.8 mM and 1.8 to 33.2 mM with and without orlistat co-administration, respectively) could be observed. The intraluminal presence of orlistat in the total jejunal samples correlated with the increased fenofibrate solubilisation in the jejunum (r = 0.9344) and enhanced absorption (r = 0.8184), highlighting the importance of the intraluminal lipid phase in lipophilic drug absorption.

The Influence of Fed State Lipolysis Inhibition on the Intraluminal Behaviour and Absorption of Fenofibrate from a Lipid-Based Formulation

The bioavailability of lipophilic drugs may or may not be increased when administered with food due to increased solubilisation in fed state gastrointestinal (GI) fluids. The in vivo interplay between drug solubilisation, lipid phase digestion and drug absorption is complex and remains poorly understood. This study aimed to investigate the role of fed state GI lipolysis on the intraluminal behaviour and absorption of fenofibrate, formulated as the lipid-based formulation Fenogal. Therefore, a crossover study was performed in healthy volunteers using orlistat as lipase inhibitor. Fenofibrate concentrations were determined in the proximal jejunum and linked to simultaneously assessed systemic fenofibric acid concentrations. Inhibition of lipolysis by orlistat resulted in a faster onset of absorption in 4 out of 6 volunteers, reflected by a decrease in systemic Tmax between 20 and 140 min. In addition, the increase of undigested lipids present in the small intestine upon orlistat co-administration sustained drug solubilisation for a longer period, resulting in higher fenofibrate concentrations in the jejunum and improved absorption in 5 out of 6 volunteers (median AUC0–8h 8377 vs. 5832 μM.min). Sustaining drug solubilisation in the lipid phase may thus contribute to the absorption of lipophilic drugs. More research into the different mechanisms underlying lipophilic drug absorption from fed state media at different levels of digestion is warranted.

Predicting Oral Absorption of fenofibrate in Lipid-Based Drug Delivery Systems by Combining In Vitro Lipolysis with the Mucus-PVPA Permeability Model

The aim of this work was to develop a new in vitro lipolysis-permeation model to predict the in vivo absorption of fenofibrate in self-nanoemulsifying drug delivery systems (SNEDDSs). More specifically, the in vitro intestinal lipolysis model was combined with the mucus-PVPA (Phospholipid Vesicle-based Permeation Assay) in vitro permeability model. Biosimilar mucus (BM) was added to the surface of the PVPA barriers to closer simulate the intestinal mucosa. SNEDDSs for which pharmacokinetic data after oral dosing to rats was available in the literature were prepared, and the ability of the SNEDDSs to maintain fenofibrate solubilized during in vitro lipolysis was determined, followed by the assessment of drug permeation across the mucus-PVPA barriers. The amount of drug solubilized over time during in vitro lipolysis did not correlate with the AUC (area under the curve) of the plasma drug concentration curve. However, the AUC of the drug permeated after in vitro lipolysis displayed a good correlation with the in vivo AUC (R2 > 0.9). Thus, it was concluded that the in vitro lipolysis–mucus-PVPA permeation model, simulating the physiological digestion and absorption processes, was able to predict in vivo absorption data, exhibiting great potential for further prediction of in vivo performance of SNEDDSs.

Self-Nanoemulsifying Drug Delivery Systems (SNEDDS) Containing Rice Bran Oil for Enhanced Fenofibrate Oral Delivery: In Vitro Digestion, Ex Vivo Permeability, and In Vivo Bioavailability Studies.

Lipid-based drug delivery systems (LbDDS), such as self-nanoemulsifying drug delivery systems (SNEDDS), constitute a prominent formulation approach for enhancing the aqueous solubility and oral bioavailability of poorly water-soluble compounds. Utilization of biorefinery wastes, such as oil from rice bran, may prove advantageous to both improving drug solubilization and absorption and to achieving sustainable agri-food waste valorization. Here, we assessed the effect of four SNEDDS compositions differing in the oil (rice bran oil and corn oil) and surfactant type (Kolliphor RH40 and EL) on the oral bioavailability of fenofibrate, a BCS class II compound. Prior to the in vivo oral administration of the SNEDDS in rats, drug solubilization was tested in vitro using the static digestion model, followed by the ex vivo permeability study of the predigested SNEDDS using the non-everted gut sac model. No significant variation was observed in the solubilization capacity within the different SNEDDS formulations. On the other hand, the ex vivo permeability data of the predigested SNEDDS correlated well with the in vivo bioavailability data designating the superiority of rice bran oil with Kolliphor EL as the surfactant, to enhance the oral absorption of fenofibrate. Results indicated that valorization of agro-industrial waste such as rice bran oil may prove useful in enhancing the oral performance of LbDDS in the case of fenofibrate, while at the same time maximizing the use of agricultural by-products via the creation of new sustainable value chains in the pharmaceutical field.

Quantifying In Vivo Luminal Drug Solubilization -Supersaturation-Precipitation Profiles to Explain the Performance of Lipid Based Formulations.

To evaluate the role of supersaturation in the in vivo absorption of fenofibrate (FFB), after oral administration in a medium-chain lipid-based formulation (MCLBF). FFB was loaded at 90% and 20% w/w of saturated solubility in MCLBF. The two formulations were pre-dispersed in purified water at 5% w/w (ME90% and 20%, respectively) and orally administered to rats to measure in vivo luminal drug concentrations. FFB precipitated in the stomach due to lipid digestion by gastric lipases and loss of solubilization capacity. This was most significant for ME90%. For ME90%, a high degree of supersaturation was also observed in the duodenum, however, precipitated FFB crystals rapidly re-dissolved. The combination of supersaturation and rapid re-dissolution appeared to drive effective absorption in the upper intestine. For ME20%, FFB precipitated in the stomach but not in the crystalline form and rapidly re-dissolved. Supersaturation in the duodenum again appeared to be the major driver of oral absorption. The data provide one of the first studies of in vivo luminal drug concentration, supersaturation and absorption from lipid based formulations and suggests that for FFB, whilst very high supersaturation may drive in vitro and in vivo precipitation, re-dissolution and drug absorption is rapid and efficient.

Using in vitro lipolysis and SPECT/CT in vivo imaging to understand oral absorption of fenofibrate from lipid-based drug delivery systems

Using lipid-based drug delivery systems (LbDDS) is an efficient strategy to enhance the low oral bioavailability of poorly water-soluble drugs. Here the oral absorption of fenofibrate (FF) from LbDDS in rats was investigated in pharmacokinetic, in vitro lipolysis, and SPECT/CT in vivo imaging studies. The investigated formulations were soybean oil solution (SBO), a mixture of soybean oil and monoacyl phosphatidylcholine (MAPC) (SBO-MAPC), self-nanoemulsifying drug delivery systems with and without MAPC (SNEDDS-MAPC and SNEDDS, respectively), and an aqueous suspension (SUSP) as a reference. Oral bioavailability of the LbDDS ranged from 27 to 35%. A two-step in vitro lipolysis model simulating rat gastro-intestinal digestion provided in vitro FF solubilisation data to understand oral absorption. During the in vitro lipolysis, most FF was undissolved for SUSP and distributed into the poorly dispersed oil phase for SBO. For the SNEDDS without MAPC, practically all FF solubilised into the aqueous phase during the dispersion and digestion. Adding MAPC to SBO enhanced the dispersion of the oil phase into the digestion media while adding MAPC to SNEDDS resulted in a distribution of 29% of FF into the oil phase at the beginning of in vitro lipolysis. FF distribution into both oil and aqueous phases explained the higher and prolonged oral absorption of LbDDS containing MAPC. To elucidate the relatively low bioavailability of all formulations, FF and triolein were labeled with 123I and 125I, respectively, to study the biodistribution of drug and lipid excipients in a dual isotope SPECT/CT in vivo imaging study. The concentration of radiolabeled drug as a function of time in the heart correlated to the plasma curves. A significant amount of radiolabeled drug and lipids (i.e., 28–59% and 24–60% of radiolabeled drug and lipids, respectively) was observed in the stomach at 24 h post administration, which can be linked to the low bioavailability of the formulations. The current study for the first time combined in vitro lipolysis and dual isotope in vivo imaging to find the root cause of different fenofibrate absorption profiles from LbDDS and an aqueous suspension.

Fenofibrate oral absorption from SNEDDS and super-SNEDDS is not significantly affected by lipase inhibition in rats

The effect of drug load and digestion on the solubilization and absorption of fenofibrate in self-nanoemulsifying drug delivery system (SNEDDS) was assessed in a pharmacokinetic study in rats and in an in vitro lipolysis model. SNEDDS containing fenofibrate at 75% of equilibrium solubility (Seq), a super-saturated SNEDDS (super-SNEDDS) containing fenofibrate at 150% of Seq and a super-SNEDDS suspension containing fenofibrate at 100% of Seq and an additional 50% Seq fenofibrate suspended (150% of Seq in total) were used. To assess the effect of lipid digestion on fenofibrate absorption in rats and fenofibrate solubilization during in vitro lipolysis, the lipase inhibitor orlistat was added at 1% (w/w) to the SNEDDS, resulting in six different SNEDDS: SNEDDS, super-SNEDDS and super-SNEDDS suspension with and without orlistat 1% (w/w). In vivo, super-SNEDDS had a higher Cmax and AUC0-30h compared to SNEDDS and super-SNEDDS suspension, both with and without orlistat. While orlistat did not affect fenofibrate absorption in SNEDDS and super-SNEDDS, an increase of Tmax and AUC0-30h for super-SNEDDS suspension was found when orlistat was present. During in vitro lipolysis, the addition of orlistat decreased digestion and lowered drug precipitation. Super-SNEDDS showed significantly increased absorption in rats compared to SNEDDS and super-SNEDDS suspension and the inhibition of digestion resulted in prolonged and increased absorption for the super-SNEDDS suspension.

Effect of molecular weight of hypromellose on mucin diffusion and oral absorption behavior of fenofibrate nanocrystal

We investigated the effect of variation in the molecular weight of hypromellose (HPMC) on the oral absorption of fenofibrate (FFB) nanocrystal. Four types of HPMC with different molecular weights and sodium dodecyl sulfate (SDS) were used as dispersion stabilizers for FFB nanocrystal suspension. Wet-milling of FFB crystal with HPMC and SDS formed diamond-shaped FFB nanocrystals with approximately 150 nm diameter. HPMC was strongly adsorbed onto the FFB nanocrystal interface, and the amount of HPMC adsorbed was not dependent on the molecular weight of HPMC. However, the decrease in the molecular weight of adsorbed HPMC led to an improvement in the permeability of FFB nanocrystal through the mucin layer. The decrease in molecular weight of HPMC enhanced the flexibility of FFB nanocrystal interface and effectively inhibited its interaction with mucin. This led to faster diffusion of FFB nanocrystal through mucin. In vivo oral absorption studies showed rapid FFB absorption from FFB nanocrystal formulations using HPMC of low molecular weights. The present study revealed that the molecular weight of the dispersion stabilizer for drug nanocrystal formulation should be taken into consideration to achieve improved absorption of poorly water-soluble drugs after oral administration.

Combined effects of the drug distribution and mucus diffusion properties of self-microemulsifying drug delivery systems on the oral absorption of fenofibrate

We present the absorption improvement mechanism of fenofibrate (FFB), a Biopharmaceutics Classification System (BCS) class II drug, from self-microemulsifying drug delivery systems (SMEDDS), centered on improving the diffusion of FFB through the unstirred water layer (UWL). Four SMEDDS formulations containing Labrafac™ lipophile WL 1349 (WL1349) or Labrafil® M 1944CS (M1944) oils and NIKKOL HCO-40 (HCO40) or NIKKOL HCO-60 (HCO60) surfactants were prepared. Every SMEDDS formulation formed microemulsion droplets of approximately 30 nm. In vitro tests showed that the microemulsion droplets containing M1944 had relatively small FFB solubilization capacities, causing larger amounts of FFB to be dissolved in the bulk water phase, compared to the droplets containing WL1349. The diffusivity of the microemulsion droplets through the mucin solution layer was enhanced when using HCO40 compared to HCO60. The oral absorption in rats was the highest when using the SMEDDS formulation containing M1944 and HCO40. High FFB distribution in the bulk water phase and fast diffusion of microemulsion droplets through the mucus layer contributed to the efficient delivery of FFB molecules through the UWL to the epithelial cells, leading to enhanced FFB absorption.

Polymeric Precipitation Inhibitors Promote Fenofibrate Supersaturation and Enhance Drug Absorption from a Type IV Lipid-Based Formulation.

The ability of lipid-based formulations (LBFs) to increase the solubilization, and prolong the supersaturation, of poorly water-soluble drugs (PWSDs) in the gastrointestinal (GI) fluids has generated significant interest in the past decade. One mechanism to enhance the utility of LBFs is to prolong supersaturation via the addition of polymers that inhibit drug precipitation (polymeric precipitation inhibitors or PPIs) to the formulation. In this work, we have evaluated the performance of a range of PPIs and have identified PPIs that are sufficiently soluble in LBF to allow the construction of single phase formulations. An in vitro model was first employed to assess drug (fenofibrate) solubilization and supersaturation on LBF dispersion and digestion. An in vitro-in situ model was subsequently employed to simultaneously evaluate the impact of PPI enhanced drug supersaturation on drug absorption in rats. The stabilizing effect of the polymers was polymer specific and most pronounced at higher drug loads. Polymers that were soluble in LBF allowed simple processing as single phase formulations, while formulations containing more hydrophilic polymers required polymer suspension in the formulation. The lipid-soluble polymers Eudragit (EU) RL100 and poly(propylene glycol) bis(2-aminopropyl ether) (PPGAE) and the water-soluble polymer hydroxypropylmethyl cellulose (HPMC) E4M were identified as the most effective PPIs in delaying fenofibrate precipitation in vitro. An in vitro model of lipid digestion was subsequently coupled directly to an in situ single pass intestinal perfusion assay to evaluate the influence of PPIs on fenofibrate absorption from LBFs in vivo. This coupled model allowed for real-time evaluation of the impact of supersaturation stabilization on absorptive drug flux and provided better discrimination between the different PPIs and formulations. In the presence of the in situ absorption sink, increased fenofibrate supersaturation resulted in increased drug exposure, and a good correlation was found between the degree of in vitro supersaturation and in vivo drug exposure. An improved in vitro-in vivo correlation was apparent when comparing the same formulation under different supersaturation conditions. These observations directly exemplify the potential utility of PPIs in promoting drug absorption from LBF, via stabilization of supersaturation, and further confirm that relatively brief periods of supersaturation may be sufficient to promote drug absorption, at least for highly permeable drugs such as fenofibrate.

A mechanism-based pharmacokinetic model of fenofibrate for explaining increased drug absorption after food consumption

BackgroundOral administration of drugs is convenient and shows good compliance but it can be affected by many factors in the gastrointestinal (GI) system. Consumption of food is one of the major factors affecting the GI system and consequently the absorption of drugs. The aim of this study was to develop a mechanistic GI absorption model for explaining the effect of food on fenofibrate pharmacokinetics (PK), focusing on the food type and calorie content.MethodsClinical data from a fenofibrate PK study involving three different conditions (fasting, standard meals and high-fat meals) were used. The model was developed by nonlinear mixed effect modeling method. Both linear and nonlinear effects were evaluated to explain the impact of food intake on drug absorption. Similarly, to explain changes in gastric emptying time for the drug due to food effects was evaluated.ResultsThe gastric emptying rate increased by 61.7% during the first 6.94 h after food consumption. Increased calories in the duodenum increased the absorption rate constant of the drug in fed conditions (standard meal = 16.5%, high-fat meal = 21.8%) compared with fasted condition. The final model displayed good prediction power and precision.ConclusionsA mechanistic GI absorption model for quantitatively evaluating the effects of food on fenofibrate absorption was successfully developed, and acceptable parameters were obtained. The mechanism-based PK model of fenofibrate can quantify the effects of food on drug absorption by food type and calorie content.

The artificial membrane insert system as predictive tool for formulation performance evaluation

In view of the increasing interest of pharmaceutical companies for cell- and tissue-free models to implement permeation into formulation testing, this study explored the capability of an artificial membrane insert system (AMI-system) as predictive tool to evaluate the performance of absorption-enabling formulations. Firstly, to explore the usefulness of the AMI-system in supersaturation assessment, permeation was monitored after induction of different degrees of loviride supersaturation. Secondly, to explore the usefulness of the AMI-system in formulation evaluation, a two-stage dissolution test was performed prior to permeation assessment. Different case examples were selected based on the availability of in vivo (intraluminal and systemic) data: (i) a suspension of posaconazole (Noxafil®), (ii) a cyclodextrin-based formulation of itraconazole (Sporanox®), and (iii) a micronized (Lipanthyl®) and nanosized (Lipanthylnano®) formulation of fenofibrate. The obtained results demonstrate that the AMI-system is able to capture the impact of loviride supersaturation on permeation. Furthermore, the AMI-system correctly predicted the effects of (i) formulation pH on posaconazole absorption, (ii) dilution on cyclodextrin-based itraconazole absorption, and (iii) food intake on fenofibrate absorption. Based on the applied in vivo/in vitro approach, the AMI-system combined with simple dissolution testing appears to be a time- and cost-effective tool for the early-stage evaluation of absorption-enabling formulations.

Transient Supersaturation Supports Drug Absorption from Lipid-Based Formulations for Short Periods of Time, but Ongoing Solubilization Is Required for Longer Absorption Periods.

The current studies sought to explore the impact of drug supersaturation and precipitation during the dispersion and digestion of lipid-based formulations (LBFs), on in vivo absorption using a coupled in vitro digestion-in vivo perfusion absorption model. Fenofibrate absorption was evaluated from a number of LBFs with different solubilization and supersaturation capacities, and conditions at the absorptive membrane manipulated by changing perfusion conditions, intestine segment lengths, and by the conduct of experiments in the presence or absence of suspended/precipitated drug. LBF dispersion and digestion resulted in varying periods of supersaturation across the different formulations. Even fleeting (5-10 min) periods of supersaturation were able to drive flux across a perfused 10 cm intestinal segment for up to 60 min, although over longer infusion periods (60-80 min) flux dropped in the absence of ongoing drug solubilization and supersaturation. In contrast, the presence or absence of precipitated/suspended drug, had little impact on drug flux. When perfused intestinal segment lengths were extended, the role of initial supersaturation was attenuated and ongoing solubilization conditions became the primary driver of absorptive flux. The data suggest that for highly permeable drugs such as fenofibrate, a short period of supersaturation at the absorptive membrane may be sufficient to drive absorptive drug flux in spite of significant drug precipitation on formulation dispersion or digestion in vitro. In contrast, where longer periods of absorption are required, for example, at higher doses, the requirement for ongoing solubilization and supersaturation becomes more apparent.

Physicochemical Properties of Solid Phospholipid Particles as a Drug Delivery Platform for Improving Oral Absorption of Poorly Soluble Drugs.

A novel drug delivery platform, mesoporous phospholipid particle (MPP), is introduced. Its physicochemical properties and ability as a carrier for enhancing oral absorption of poorly soluble drugs are discussed. MPP was prepared through freeze-drying a cyclohexane/t-butyl alcohol solution of phosphatidylcholine. Its basic properties were revealed using scanning electron microscopy, x-ray diffraction, thermal analysis, hygroscopicity measurement, and so on. Fenofibrate was loaded to MPP as a poorly soluble model drug, and effect of MPP on the oral absorption behavior was observed. MPP is spherical in shape with a diameter typically in the range of 10-15μm and a wide surface area that exceeds 10m2/g. It has a bilayer structure that may accommodate hydrophobic drugs in the acyl chain region. When fenofibrate was loaded in MPP as a model drug, it existed partially in a crystalline state and improvement in the dissolution behavior was achieved in the presence of a surfactant, because of the formation of mixed micelles composed of phospholipids and surfactants in the dissolution media. MPP greatly improved the oral absorption of fenofibrate compared to that of the crystalline drug and its efficacy was almost equivalent to that of an amorphous drug dispersion. MPP is a promising option for improving the oral absorption of poorly soluble drugs based on the novel mechanism of dissolution improvement.

In Vivo Performance of Fenofibrate Formulated With Ordered Mesoporous Silica Versus 2-Marketed Formulations: A Comparative Bioavailability Study in Beagle Dogs

The present study aims to evaluate the in vitro and in vivo performance of ordered mesoporous silica (OMS) as a carrier for the poorly water-soluble compound fenofibrate. Fenofibrate was loaded into OMS via incipient wetness impregnation to obtain a 29% drug load and formulated into capsules. Two capsule dosage forms (containing 33.5 and 16.75 mg fenofibrate, respectively) were compared with the commercially available forms—Lipanthyl® (fenofibrate microcrystals) and Tricor® (fenofibrate nanocrystals). In vitro dissolution tests showed that the amount of fenofibrate released from Lipanthyl® and Tricor® was approximately 30%, whereas approximately 66% and 60% of the drug was released from OMS capsules containing 33.5 and 16.75 mg of fenofibrate, respectively. Storage of OMS capsules loaded with 33.5 mg of fenofibrate at 25°C/60% relative humidity (RH) or 40°C/75% RH did not alter the release kinetics, nor the physical state of the compound, pointing the stability of the present formulation. The in vivo study in dogs confirmed satisfying level of safety and tolerability of fenofibrate–OMS formulation (eq. 33.5 mg) with the potential to improve the absorption of fenofibrate. Though some variability in the data, this formulation is promising to be further investigated in a clinical trial setting.

Self-emulsifying drug delivery system developed by the HLB-RSM approach: Characterization by transmission electron microscopy and pharmacokinetic study

Recently, we developed a new approach to rationalize an optimized design for self-emulsifying drug delivery system (SEDDS) by introducing the HLB and the response surface as determinant factors in SEDDS development. The aim of this current paper is to assess the suitability of this HLB-RSM approach to enhance the oral bioavailability of BCS class II compounds using fenofibrate as drug model. Eight SEDDS formulations (I→VIII) were pre-selected regarding their self-emulsification capacity and their effect on increasing in vitro drug release. They were firstly evaluated for their thermodynamic stability and zeta potential. Unstable SEDDS were discarded meanwhile the structural morphology of the stable ones (I, VI and VIII) was characterized using transmission electron microscopy (TEM). A pharmacokinetic study was then undertaken on male BALB/cJRj mices. The in vivo results showed a significant increase of fenofibrate absorption for all the three stable SEDDS formulations compared to the commercialized form, (LIPANTHYL micronized® (p<0.05)). The highest enhancement was recorded for SEDDS I, where AUC and Cmax values respectively increased by 2 and 4.4 folds. This justifies the fact that HLB-RSM approach could be considered as a promising method for the development of efficient and highly stable SEDDS aiming to increase the poor bioavailability of BCS class II molecules.

Kolliphor surfactants affect solubilization and bioavailability of fenofibrate. Studies of in vitro digestion and absorption in rats.

Selection of excipients for drug formulations requires both intellectual and experimental considerations as many of the used excipients are affected by physiological factors, e.g., they may be digested by pancreatic enzymes in the gastrointestinal tract. In the present paper we have looked systematically into the differences between Kolliphor ELP, EL, and RH40 and how they affect the bioavailability of fenofibrate, through pharmacokinetic studies in rats and in vitro lipolysis studies. The study design was made as simple as possible to avoid confounding factors, for which reason the tested formulations only comprised an aqueous micellar solution of the model drug (fenofibrate) in varying concentrations (2-25% (w/v)) of the three tested surfactants. Increased concentrations of Kolliphor ELP and EL led to increased fenofibrate AUC0-24h values. For the Kolliphor RH40 formulations, an apparent fenofibrate absorption optimum was seen at 15% (w/v) surfactant, displaying both the highest AUC0-24h and Cmax. The reduced absorption of fenofibrate from the formulation containing the highest level of surfactant (25% w/v) was thought to be caused by some degree of trapping within Kolliphor RH40 micelles. In vitro, Kolliphor ELP and EL were found to be more prone to digestion than Kolliphor RH40, though not affecting the in vivo results. The highest fenofibrate bioavailability was attained from formulations with high Kolliphor ELP/EL levels (25% (w/v)), indicating that these surfactants are the better choice for solubilizing fenofibrate in order to increase the absorption upon oral administration. Due to drug dependent effects of the different types of Kolliphor, more studies are recommended in order to understand which type of Kolliphor is best suited for a given drug.

Effects of PEGylated lipid nanoparticles on the oral absorption of one BCS II drug: a mechanistic investigation.

Lipid nanocarriers are becoming a versatile platform for oral delivery of lipophilic drugs. In this article, we aimed to explore the gastrointestinal behaviors of lipid nanoparticles and the effect of PEGylation on oral absorption of fenofibrate (FN), a Biopharmaceutics Classification System (BCS) II model drug. FN-loaded PEGylated lipid nanoparticles (FN-PLNs) were prepared by the solvent-diffusion method and characterized by particle size distribution, morphology, Fourier transform infrared spectroscopy, and drug release. Lipolytic experiments were performed to assess the resistance of lipid nanoparticles against pancreatic lipase. Pharmacokinetics was evaluated in rats after oral administration of FN preparations. The obtained FN-PLNs were 186.7 nm in size with an entrapment efficiency of >95%. Compared to conventional lipid nanoparticles, PLNs exhibited slower drug release in the lipase-containing medium, strikingly reduced mucin binding, and suppressed lipolysis in vitro. Further, oral absorption of FN was significantly enhanced using PLNs with relative bioavailability of 123.9% and 157.0% to conventional lipid nanoparticles and a commercial formulation (Lipanthyl®), respectively. It was demonstrated that reduced mucin trapping, suppressed lipolysis, and/or improved mucosal permeability were responsible for increased oral absorption. These results facilitated a better understanding of the in vivo fate of lipid nanoparticles, and suggested the potential of PLNs as oral carriers of BCS II drugs.