Development of a UPLC-ESI-MS/MS assay for 20(S)-protopanaxadiol and pharmacokinetic application of its two formulations in rats

LC-MS/MS quantification of 20(S)-protopanaxadiol in complex biological matrices for bioanalytical method validation and pharmacokinetic analysis

20(S)-Protopanaxadiol (PPD) is a saponin derivative of ginsenoside, with more potent biological and pharmacological activities than Rg3 and Rh2. The lack of ionizable centers leads to low mass spectrometry reactions and internal cleavage of three hydroxyl groups, making it challenging to establish highly sensitive PPD mass spectrometry methods. The aim of this study is to establish and validate a quantitative detection method for PPD in multiple matrices using mass spectrometry. The methods used Rh2 as the internal standard and organic solvent liquid-liquid extraction under alkaline conditions for biological sample pretreatment. Isometric separation was achieved through methanol, acetonitrile, and a 10 mmol/L solution of acetic acid (45:45:10, v/v/v) at a flow rate of 0.4 mL/min. Finally, perform mass spectrometry quantification. Comprehensive method validation was conducted on rat plasma samples, and partial method validations were performed on three types of rat tissues (adipose tissue, smooth muscle, and skeletal muscle), bile, urine, fecal samples, and dog plasma samples. The results were in accordance with the requirements of NMPA for bioanalytical method validation, ensuring the accuracy and reliability of our analytical measurements. This study employed a conventional liquid-liquid extraction sample pretreatment scheme, utilizing multiple biological matrices commonly found in a single treatment protocol and liquid chromatography-tandem mass spectrometry detection parameters. The consistency of processing and detection across diverse samples eliminated the need for methodological changes, providing exceptional convenience. Up to 90% of the organic phase and a 50 mm short chromatographic column achieved rapid and effective separation of PPD. A key aspect of our work is the use of a "programmed injection" technique, which significantly reduces the analysis time from 4.2 min during method exploration to 2.4 min. These methods have achieved a relatively low quantification limit of 2.5 ng/mL. The methods established were successfully applied to the kinetic process of PPD in rats, and the pharmacokinetic characteristics of PPD in dogs were studied for the first time.

Systematic studies on the kinetic process of 20(S)-protopanaxadiol in rats and dogs: absorption, distribution, metabolism and excretion

Background and Objective

Ginseng has been regarded as a precious medicinal herb with miraculous effects in Eastern culture. The primary chemical constituents of ginseng are saponins, and the physiological activities of ginsenosides determine their edible and medicinal value. The aim of this study is to comprehensively and systematically investigate the kinetic processes of 20(S)-protopanaxadiol (PPD) in rats and dogs, in order to promote the rational combination of ginseng as a drug and dietary ingredient.

Methods

PPD was administered, and drug concentration in different biological samples were detected by liquid chromatography tandem mass spectrometry (LC/MS/MS) and radioactive tracer methods. Pharmacokinetic parameters such as absorption, bioavailability, tissue distribution, plasma protein binding rate, excretion rate, and cumulative excretion were calculated, along with inference of major metabolites.

Results

This study systematically investigated the absorption, distribution, metabolism, excretion (ADME) of PPD in rats and dogs for the first time. The bioavailabilities of PPD were relatively low, with oral absorption nearly complete, and the majority underwent first-pass metabolism. PPD had a high plasma protein binding rate and was relatively evenly distributed in the body. Following oral administration, PPD underwent extensive metabolism, potentially involving one structural transformation and three hydroxylation reactions. The metabolites were primarily excreted through feces and urine, indicating the presence of enterohepatic circulation. The pharmacokinetic processes of PPD following intravenous administration aligned well with a three-compartment model. In contrast, after gastric administration, it fitted better with a two-compartment model, conforming to linear pharmacokinetics and proportional elimination. There were evident interspecies differences between rats and dogs regarding PPD, but individual variations of this drug were minimal within the same species.

Conclusion

This study systematically studied the kinetic process of PPD in rats and also investigated the kinetic characteristics of PPD in dogs for the first time. These findings lay the foundation for further research on the dietary nutrition and pharmacological effects of PPD.

Protopanaxadiol improves lupus nephritis by regulating the PTX3/MAPK/ERK1/2 pathway

Lupus nephritis (LN) is a kidney disease that occurs after systemic lupus erythematosus (SLE) affects the kidneys. Pentraxin 3 (PTX3) is highly expressed in the serum of patients with LN. Renal PTX3 deposition is directly related to clinical symptoms such as proteinuria and inflammation. The excessive proliferation of mesangial cells (MCs) is one of the representative pathological changes in the progression of LN, which is closely related to its pathogenesis. Protopanaxadiol (PPD) is the main component of ginsenoside metabolism and has not been reported in LN. The aim of this study was to investigate the relationship between PTX3 and mesangial cell proliferation and to evaluate the potential role and mechanism of PPD in improving LN. PTX3 is highly expressed in the kidneys of LN patients and LN mice and is positively correlated with renal pathological indicators, including proteinuria and PCNA. The excessive expression of PTX3 facilitated the proliferation of MCs, facilitated the activation of the MAPK/ERK1/2 signaling pathway, and increased the expression of HIF-1α. Further studies showed that PPD can effectively inhibit the abnormal proliferation of MCs with high expression of PTX3 and significantly improve LN symptoms such as proteinuria in MRL/lpr mice. The mechanism may be related to the inhibition of the PTX3/MAPK/ERK1/2 pathway. In this study, both in vitro, in vivo, and clinical sample results show that PTX3 is involved in the regulation of MCs proliferation and the early occurrence of LN. Natural active compound PPD can improve LN by regulating the PTX3/MAPK/ERK1/2 pathway.

Biodistribution and pharmacokinetic evaluation of Korean Red Ginseng components using radioisotopes in a rat model

Background

Although many studies have evaluated the efficacy and pharmacokinetics of Korean Red Ginseng (KRG) components (Rg1, Rb1, Rg3, Rd, etc.), few have examined the in vivo pharmacokinetics of the radiolabeled components. This study investigated the pharmacokinetics of ginsenosides and their metabolite compound K (CK), 20(s)-protopanaxadiol (PPD), and 20(s)-protopanaxatriol (PPT) using radioisotopes in rat oral administration.

Methods

Sprague-Dawley rats were dosed orally once with 10 mg/kg of the tritium(3H) radiolabeled samples, and then the blood was collected from the tail vein after 0.25, 0.5, 1, 1.5, 2, 4, 6, 8, 12, 24, 48, 96, and 168 h. Radioactivity in the organs, feces, urine, and carcass was determined using a liquid scintillation counter (LSC) and a bio-imaging analyzer system (BAS).

Results and conclusion

After oral administration, as the ³H-labeled ginsenosides were converted to metabolites, C_max and half-life increased, and T_max decreased. Interestingly, Rb1 and CK showed similar values, and after a single oral administration of components, the cumulative excretion ratio of urine and feces was 88.9%-92.4%. Although most KRG components were excreted within 96-168 h of administration, small amounts of components were detected in almost all tissues and mainly distributed to the liver except for the digestive tract when observed through autoradiography. This study demonstrated that KRG components were distributed to various organs in the rats. Further studies could be conducted to prove the bioavailability and transmission of KRG components to confirm the mechanism of KRG efficacy.

Identification of Adenylate Kinase 5 as a Protein Target of Ginsenosides in Brain Tissues Using Mass Spectrometry-Based Drug Affinity Responsive Target Stability (DARTS) and Cellular Thermal Shift Assay (CETSA) Techniques

Ginseng is a very famous Chinese herbal medicine with various pharmacological effects. Ginsenosides, the main effective compounds of ginseng, show favorable biological activities in the central nervous system (CNS), but the protein targets of ginsenosides in brain tissues have not been clarified clearly. First, we screened proteins that interact with ginsenosides by mass spectrometry-based drug affinity responsive target stability (DARTS) and cellular thermal shift assay (CETSA). Then, we identified and confirmed adenylate kinase 5 (AK5) as a target protein of ginsenosides by biolayer interferometry (BLI), isothermal titration calorimetry (ITC), and molecular docking. Finally, an enzyme activity kit was used to determine the effect of 20(S)-protopanaxadiol (PPD), a ginseng saponin metabolite, on AK5 activities in vivo and in vitro. We screened out seven overlapping target proteins by proteomics of DARTS and CETSA. The BLI direct action assays showed that the direct interaction of PPD with AK5 was higher compared to the parental ginsenosides. Subsequently, BLI kinetic analysis and ITC assay showed that PPD specifically bound to AK5. Furthermore, key amino acid mutations predicted by molecular docking decreased the affinity between PPD and AK5. Enzyme activity assays showed that PPD increased AK5 activities in vivo and in vitro. The above-mentioned findings indicated that AK5 is a protein target of ginsenoside in the brain and PPD is considered to be a small-molecular activator of AK5, which can improve comprehension of the molecular mechanisms of ginseng pharmacological effects in the CNS and further develop AK5 activators based on the dammarane-type triterpenoid structure.

Enhanced the Bioavailability of Sterile 20(S)-Protopanaxadiol Nanocrystalline Suspension Coated by Bovine Serum Albumin for Intramuscular Injection: In Vitro and In Vivo Evaluation

The aim of this study was to prepare a 20(S)-protopanaxadiol nanocrystalline suspension and enhance the bioavailability of 20(S)-protopanaxadiol by intramuscular injection. 20(S)-Protopanaxadiol nanocrystalline suspension was prepared using an anti-solvent combined with ultrasonic approach, in which meglumine and bovine serum albumin were screened as the optimized stabilizer and the coating agent during spray drying process, respectively. The optimal nanocrystallines were nearly spherical with a uniform particle size distribution, the mean particle size, polydispersity index, and drug loading of which were 151.20 ± 2.54 nm, 0.11 ± 0.01, and 47.15% (w/w), respectively. Sterile 20(S)-protopanaxadiol nanocrystalline suspension was obtained by passing through a 0.22-μm membrane, and the average filtration efficiency (FE%) was 99.96%. The cumulative release percentage of 20(S)-protopanaxadiol nanocrystalline suspension was 92.36% 20(S)-protopanaxadiol within 60 min in vitro, which was relatively rapid compared with that of the physical mixture for 12.51% and the 20(S)-protopanaxadiol bulk powder for 9.71% during the same time interval. The sterile 20(S)-protopanaxadiol nanocrystalline suspension caused minimal irritation responses by histological examination, indicating a good biocompatibility between the 20(S)-protopanaxadiol nanocrystalline suspension and muscle tissues. In pharmacokinetic study, the absolute bioavailability of 20(S)-protopanaxadiol nanocrystalline suspension for intramuscular injection and for oral gavage was 5.99 and 0.03, respectively. In summary, the 20(S)-protopanaxadiol nanocrystalline via intramuscular injection is an efficient drug delivery system to improve its bioavailability.

Formulation and Characterization of Novel Dry Suspension and Dry Emulsion of 20(S)-Protopanaxadiol

To improve the absorption of poorly water-soluble 20(S)-protopanaxadiol (20(S)-PPD), novel 20(S)-PPD-loaded redispersible dry suspension and dry emulsion were developed in this study. 20(S)-PPD dry suspension (PPD-DS) was prepared by enabling drug fully dispersed with suspending agent Avicel CL611 and solubilizer Poloxamer 188. 20(S)-PPD dry emulsion (PPD-DE) was prepared by employing oleic acid as oil phase, Cremophor RH-40 as surfactant, and n-butyl alcohol as co-surfactant. Both PPD-DS and PPD-DE were evaluated for their physicochemical characterization after being dispersed in distilled water. The in vivo pharmacokinetics was evaluated by UPLC-MS/MS. The droplet size of PPD-DS and PPD-DE was in the scope of 1446-1653 nm and 652.8-784.5 nm. The sedimentation volume ratios of PPD-DS and PPD-DE were both at value of 1. The zeta potential of PPD-DS and PPD-DE were from - 53.7 to - 70.4 mV and - 27.5 to - 34.5 mV, respectively, which indicated stable systems. PPD-DS and PPD-DE both achieved dramatically enhanced aqueous solubility and higher perfusion of 20(S)-PPD in rats' intestine. Although statistically, no oral bioavailability enhancements of 20(S)-PPD were achieved in PPD-DE and PPD-DS, there were some improvements in the pharmacokinetic behaviors. Especially, PPD-DS could be a promising drug delivery carrier for 20(S)-PPD with the advantages of long-term stability, dosing flexibility, and the convenience of administering to infants and to those who have difficulty swallowing tablets or capsules.

Micro-/nano-sized delivery systems of ginsenosides for improved systemic bioavailability

Ginsenosides, dammarane-type triterpene saponins obtained from ginseng, have been used as a natural medicine for many years in the Orient due to their various pharmacological activities. However, the therapeutic potential of ginsenosides has been largely limited by the low bioavailability of the natural products caused mainly by low aqueous solubility, poor biomembrane permeability, instability in the gastrointestinal tract, and extensive metabolism in the body. To enhance the bioavailability of ginsenosides, diverse micro-/nano-sized delivery systems such as emulsions, polymeric particles, and vesicular systems have been investigated. The delivery systems improved the bioavailability of ginsenosides by enhancing solubility, permeability, and stability of the natural products. This mini-review aims to provide comprehensive information on the micro-/nano-sized delivery systems for increasing the bioavailability of ginsenosides, which may be helpful for designing better delivery systems to maximize the versatile therapeutic potential of ginsenosides.

Polycaprolactone nanofibres loaded with 20(S)-protopanaxadiol for in vitro and in vivo anti-tumour activity study

In this work, 20(S)-protopanaxadiol (PPD)-loaded polycaprolactone (PCL) nanofibres were successfully fabricated by the electrospinning technique using Tween 80 as a solubilizer. Firstly, smooth and continuous nanofibres were collected using suitable solvents and appropriate spinning conditions. Secondly, nanofibre mats were characterized by scanning electron microscopy, thermogravimetric (TG) analysis, Fourier transform infrared spectroscopy and mechanical testing. Finally, nanofibrous membranes were evaluated using water contact angle, in vitro drug release, biodegradation test, in vitro and in vivo anti-tumour activity and cell apoptosis assay. Scanning electron microscopic observations indicated that the diameter of the drug-loaded nanofibres increased with the increase of drug concentration. TG analysis and mechanical test showed that nanofibres were equipped with great thermal and mechanical properties. Biodegradation test exhibited that the structure of fabricated nanofibres had a certain degree of change after 15 days. An in vitro release study showed that PPD from drug-loaded nanofibres could be released in a sustained and prolonged mode. The cytotoxic effect of drug-loaded nanofibre mats examined on human laryngeal carcinoma cells (Hep-2 cells) demonstrated that the prepared nanofibres had a remarkable anti-tumour effect. Meanwhile, the drug-loaded fibre mats showed a super anti-tumour effect in an in vivo anti-tumour study. All in all, PCL nanofibres could be a potential carrier of PPD for cancer treatment.

Polycaprolactone nanofibres loaded with 20(S)-protopanaxadiol for in vitro and in vivo anti-tumour activity study

In this work, 20(S)-protopanaxadiol (PPD)-loaded polycaprolactone (PCL) nanofibres were successfully fabricated by the electrospinning technique using Tween 80 as a solubilizer. Firstly, smooth and continuous nanofibres were collected using suitable solvents and appropriate spinning conditions. Secondly, nanofibre mats were characterized by scanning electron microscopy, thermogravimetric (TG) analysis, Fourier transform infrared spectroscopy and mechanical testing. Finally, nanofibrous membranes were evaluated using water contact angle, in vitro drug release, biodegradation test, in vitro and in vivo anti-tumour activity and cell apoptosis assay. Scanning electron microscopic observations indicated that the diameter of the drug-loaded nanofibres increased with the increase of drug concentration. TG analysis and mechanical test showed that nanofibres were equipped with great thermal and mechanical properties. Biodegradation test exhibited that the structure of fabricated nanofibres had a certain degree of change after 15 days. An in vitro release study showed that PPD from drug-loaded nanofibres could be released in a sustained and prolonged mode. The cytotoxic effect of drug-loaded nanofibre mats examined on human laryngeal carcinoma cells (Hep-2 cells) demonstrated that the prepared nanofibres had a remarkable anti-tumour effect. Meanwhile, the drug-loaded fibre mats showed a super anti-tumour effect in an in vivo anti-tumour study. All in all, PCL nanofibres could be a potential carrier of PPD for cancer treatment.

Characterization, Molecular Docking, and In Vitro Dissolution Studies of Solid Dispersions of 20(S)-Protopanaxadiol

In this study, we prepared solid dispersions (SDs) of 20(S)-protopanaxadiol (PPD) using a melting-solvent method with different polymers, in order to improve the solubility and dissolution performance of drugs with poor water solubility. The SDs were characterized via differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), and molecular docking and dynamics study. DSC and PXRD results indicated that PPD crystallinity in SDs was significantly reduced, and that the majority of PPD is amorphous. No interaction was observed between PPD and polymers on FTIR and NMR spectra. Molecular docking and dynamic calculations indicated that the PPD molecule localized to the interpolated charged surface, rather than within the amorphous polymer chain network, which might help prevent PPD crystallization, consequently enhancing the PPD dispersion in polymers. An in vitro dissolution study revealed that the SDs considerably improved the PPD dissolution performance in distilled water containing 0.35% Tween-80 (T-80). Furthermore, among three PPD-SDs formulations, Poloxamer188 (F68) was the most effective in improving the PPD solubility and was even superior to the mixed polymers. Therefore, the SD prepared with F68 as a hydrophilic polymer carrier might be a promising strategy for improving solubility and in vitro dissolution performance. F68-based SD, containing PPD with a melting-solvent preparation method, can be used as a promising, nontoxic, quick-release, and effective intermediate for other pharmaceutical formulations, in order to achieve a more effective drug delivery.

Development and validation of an UPLC-Q/TOF-MS assay for the quantitation of neopanaxadiol in beagle dog plasma: Application to a pharmacokinetic study

Neopanaxadiol (NPD), the main panaxadiol constituent of Panax ginseng C. A. Meyer (Araliaceae), has been regarded as the active component for the treatment of Alzheimer's disease. However, few references are available about pharmacokinetic evaluation for NPD. Accordingly, a rapid and sensitive method for quantitative analysis of NPD in beagle dog plasma based on ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry was developed and validated. Analytes were extracted from plasma by liquid-liquid extraction and chromatographic separation was achieved on an Agilent Zorbax Stable Bond C₁₈ column. Detection was performed in the positive ion mode using multiple reaction monitoring of the transitions both at m/z 461.4 → 425.4 for NPD and internal standard of panaxadiol. All validation parameters, such as lower limit of quantitation, linearity, specificity, precision, accuracy, extraction recovery, matrix effect and stability, were within acceptable ranges and the method was appropriate for multitude sample determination. After oral intake, NPD was slowly absorbed and eliminated from circulatory blood system and corresponding plasma exposure was low. Application of this quantitative method will yield the first pharmacokinetic profile after oral administration of NPD to beagle dog. The information obtained here will be useful to understand the pharmacological effects of NPD.

20(S)-Protopanaxadiol Phospholipid Complex: Process Optimization, Characterization, In Vitro Dissolution and Molecular Docking Studies

20(S)-Protopanaxadiol (PPD), a bioactive compound extracted from ginseng, possesses cardioprotective, neuroprotective, anti-inflammatory, antiestrogenic, anticancer and anxiolytic effects. However, the clinical application of PPD is limited by its weak aqueous solubility. In this study, we optimized an efficient method of preparing its phospholipid complex (PPD-PLC) using a central composite design and response surface analysis. The prepared PPD-PLC was characterized by differential scanning calorimetric, powder X-ray diffraction, Fourier-transformed infrared spectroscopy and nuclear magnetic resonance analyses associated with molecular docking calculation. The equilibrium solubility of PPD-PLC in water and n-octanol increased 6.53- and 1.53-times, respectively. Afterwards, using PPD-PLC as the intermediate, the PPD-PLC-loaded dry suspension (PPD-PLC-SU) was prepared with our previous method. In vitro evaluations were conducted on PPD-PLC and PPD-PLC-SU, including dissolution behaviors and stability properties under different conditions. Results of in vitro dissolution behavior revealed the improved dissolution extents and rates of PPD-PLC and PPD-PLC-SU (p < 0.05). Results of the formulation stability investigation also exposed the better stability of PPD-PLC-SU compared with free PPD. Therefore, phospholipid complex technology is a useful formulation strategy for BCS II drugs, as it could effectively improve their hydrophilicity and lipophilicity.

A nanoparticulate drug-delivery system for 20(S)-protopanaxadiol: formulation, characterization, increased oral bioavailability and anti-tumor efficacy

As with many other hydrophobic anticancer agents, 20(S)-protopanaxadiol (PPD) has a very low oral bioavailability. In this study, a precipitation-combined ultrasonication technique was used to prepare PPD nanosuspensions. The mean particle size of the nanosuspensions was approximately 222 ± 12 nm, the drug payload achieved 50% after lyophilization and the maximum PPD concentration can reach 100 mg/ml, which is over 30 000 times the solubility of PPD in aqueous solution (3 μg/ml). After oral administration, the C_max and AUC_last values of PPD nanosuspensions were approximately 3.66-fold and 3.48-fold as those of PPD coarse suspensions, respectively. In contrast to the free drug solution, PPD nanosuspensions showed higher in vitro anti-tumor activity against HepG-2 cells (an IC₅₀ value of 1.40 versus 5.83 μg/ml at 24 h, p < 0.01). The in vivo study in H22-tumor-bearing mice demonstrated that PPD nanosuspensions showed good anti-tumor efficacy with an inhibition rate of 79.47% at 100 mg/kg, while 50 mg/kg of cyclophosphamide was displayed as positive control, and the inhibition rate was 87.81%. Considering the highest drug payload, oral bioavailability reported so far, significant anti-tumor efficacy and excellent safety of encapsulated drugs, PPD nanosuspensions could be used in potential effective strategies for anticancer therapy; further investigation is ongoing.

Lithium adduct as precursor ion for sensitive and rapid quantification of 20 (S)-protopanaxadiol in rat plasma by liquid chromatography/quadrupole linear ion trap mass spectrometry and application to rat pharmacokinetic study

A novel, rapid and sensitive liquid chromatography/quadrupole linear ion trap mass spectrometry [LC-ESI-(QqLIT)MS/MS] method was developed and validated for the quantification of protopanaxadiol (PPD) in rat plasma. Oleanolic acid (OA) was used as internal standard (IS). A simple protein precipitation based on acetonitrile (ACN) was employed. Chromatographic separation was performed on a Sepax GP-C18 column (50 × 2.1 mm, 5 μM) with a mobile phase consisting of ACN-water and 1.5 μM formic acid and 25 mM lithium acetate (90 : 10, v/v) at a flow rate of 0.4 ml/min for 3.0 min. Multiple-reaction-monitoring mode was performed using lithium adduct ion as precursor ion of m/z 467.5/449.4 and 455.6/407.4 for the drug and IS, respectively. Calibration curve was recovered over a concentration range of 0.5-100 ng/ml with a correlation coefficient >0.99. The limit of detection was 0.2 ng/ml in rat plasma for PPD. The results of the intraday and interday precision and accuracy studies were well within the acceptable limits. The validated method was successfully applied to investigate the pharmacokinetic study of PPD after intravenous and gavage administration to rat.

Enhanced oral absorption of 20(S)-protopanaxadiol by self-assembled liquid crystalline nanoparticles containing piperine: in vitro and in vivo studies

Background

20(S)-protopanaxadiol (PPD), similar to several other anticancer agents, has low oral absorption and is extensively metabolized. These factors limit the use of PPD for treatment of human diseases.

Methods

In this study, we used cubic nanoparticles containing piperine to improve the oral bioavailability of PPD and to enhance its absorption and inhibit its metabolism. Cubic nanoparticles loaded with PPD and piperine were prepared by fragmentation of glyceryl monoolein (GMO)/poloxamer 407 bulk cubic gel and verified using transmission electron microscopy and differential scanning calorimetry. We evaluated the in vitro release of PPD from these nanoparticles and its absorption across the Caco-2 cell monolayer model, and subsequently, we examined the bioavailability and metabolism of PPD and its nanoparticles in vivo.

Results

The in vitro release of PPD from these nanoparticles was less than 5% at 12 hours. PPD-cubosome and PPD-cubosome loaded with piperine (molar ratio PPD/piperine, 1:3) increased the apical to basolateral permeability values of PPD across the Caco-2 cell monolayer from 53% to 64%, respectively. In addition, the results of a pharmacokinetic study in rats showed that the relative bioavailabilities of PPD-cubosome [area under concentration–time curve (AUC)_0–∞] and PPD-cubosome containing piperine (AUC_0–∞) compared to that of raw PPD (AUC_0–∞) were 166% and 248%, respectively.

Conclusion

The increased bioavailability of PPD-cubosome loaded with piperine is due to an increase in absorption and inhibition of metabolism of PPD by cubic nanoparticles containing piperine rather than because of improved release of PPD. The cubic nanoparticles containing piperine may be a promising oral carrier for anticancer drugs with poor oral absorption and that undergo extensive metabolism by cytochrome P450.