Relative Oral Bioavailability Research Articles

Geogenic nickel exposure from food consumption and soil ingestion: A bioavailability based assessment

Accumulation and oral bioavailability of nickel (Ni) were rarely assessed for staple crops grown in high geogenic Ni soils. To assess exposure risk of geogenic Ni, soil, wheat, and rice samples were collected from a naturally high background Ni area and measured for Ni oral relative bioavailability (RBA, relative to NiSO4) using a newly developed mouse urinary Ni excretion bioassay. Results showed that soils were enriched with Ni (80.5 ± 23.0 mg kg−1, n = 58), while high Ni contents were observed in rice (2.66 ± 1.46 mg kg−1) and wheat (1.32 ± 0.78 mg kg−1) grains, with rice containing ∼2-fold higher Ni content than wheat. Ni-RBA was low in soil (14.8 ± 7.79%, n = 18), but high in wheat and rice with rice Ni-RBA (85.9 ± 19.1%, n = 9) being ∼2-fold higher than wheat (46.1 ± 21.2%, n = 16). A negative correlation (r = 0.61) was observed between Ni-RBA and iron content in rice and wheat, suggesting the low iron status of rice drives its high Ni bioavailability. The higher Ni accumulation and bioavailability for rice highlights that rice consumption was a more important contributor to daily Ni intake compared to wheat, while Ni intake from direct soil ingestion was negligible. This study suggests a potential health risk of staple crops especially rice when grown in high geogenic Ni areas.

Synthesis and characterization of pre-activated thiolated chitosan nanoparticles for oral delivery of octreotide

The study was designed to develop a nano-based delivery system for oral delivery of octreotide (OT), a peptide drug. The preactivated thiolated chitosan (PTCS) nanoparticles loaded with OT were successfully developed and characterized in vitro and in vivo. Chitosan (CS) was modified to thiolated chitosan (TCS) and preactivated thiolated chitosan (PTCS) by attaching thioglycolic acid and mercaptonicotinic acid to CS. The OT was encapsulated during NPs production, via ionic gelation technique. The PTCS-NPs had a mean size of 277 ± 19 nm, a zeta potential of +28.2 ± 3 mV with 0.2 PDI and a high payload of OT (89 ± 6%). The mucoadhesive properties of PTCS-NPs were 3- and 16-fold increased as compared to corresponding TCS and CS-NPs respectively. The sustained release of OT from PTCS-NPs over 24 h was observed with non-Fickian release kinetics. The improvement in relative oral bioavailability showed more than 4-fold improvement in elimination half-life, a ~3.4-fold enhancement in Cmax and 7.2-fold enhanced AUC(0-t) as compared to OT solution. Thus the results suggested the success of PTCS-NPs a potential oral delivery system for macromolecules due to the improved mucosal residence time, sustained release and facilitated transport via intestinal tight junctions.

A Novel Prototype Device for Microencapsulation of Benznidazole: In Vitro/In Vivo Studies.

This study was aimed to design a simple and novel prototype device for the production of polymeric microparticles. To prove the effectiveness of this device, benznidazole microparticles using chitosan as carrier and NaOH, KOH, or SLS as counter ions were used. For comparison, benznidazole microparticles were prepared by the conventional dripping technique (syringe and gauge) using the same excipients. Microparticles were characterized in terms of encapsulation efficiency, particle shape, size and surface topography, crystallinity characteristics, thermal behavior, and dissolution rate. Then, the pharmacokinetic parameters were evaluated after the oral administration of the microparticles to healthy Wistar rats. The prepared formulations, by means of this device, showed good drug encapsulation efficiency (> 70%). Release studies revealed an increased dissolution of benznidazole from chitosan microparticles prepared using the novel device. It achieved more than 90% in 60min, while those of the conventional microparticles and raw drug achieved 65% and 68%, respectively, during the same period. Almost spherical benznidazole microparticles with a smooth surface and size around 10-30μm were observed using scanning electron microscopy. Thermal analysis and X-ray diffraction studies suggested a partial reduction of drug crystallinity. Moreover, the relative oral bioavailability of the novel benznidazole microparticles showed that the area under the curve for the microencapsulated drug was 10.3 times higher than the raw drug. Thus, these findings indicate that the designed glass prototype device is a useful alternative to formulate benznidazole polymeric microparticles with improved biopharmaceutical properties and could be useful for other therapeutic microparticulate systems.

Risk assessment implications of site-specific oral relative bioavailability factors and dermal absorption fractions for polycyclic aromatic hydrocarbons in surface soils impacted by clay skeet target fragments

Risk assessment conclusions for a site may differ when using site-specific versus default values for the relative bioavailability factor (RBAF) and dermal absorption fraction (ABS.d), because these inputs affect both surface soil screening levels and risk/hazard estimates. Indeed, our case study demonstrates that different conclusions may be reached as to regulatory need for remedial action to protect human health when evaluating soil sampling data for seven carcinogenic polycyclic aromatic hydrocarbons (PAHs) using site-specific versus default TCEQ and USEPA residential soil screening levels. Use of site-specific RBAF and ABS.d values increased carcinogenicity-based TCEQ and USEPA surface soil screening levels for PAHs by 4.4- and 6-fold on average, respectively. Soil screening levels for PAHs were more sensitive to changes in ingestion exposure route parameters than to changes in dermal exposure route parameters. Accordingly, site-specific RBAF and ABS.d information has important implications for screening chemicals at PAH-impacted sites, and in addition provides more realistic estimates of risks/hazards posed by PAHs in soil with reduced uncertainty compared to estimates based on default RBAF and ABS.d values. Although default values are generally deemed acceptable by regulatory agencies, use of risk/hazard estimates based on these default values may compel insufficiently justified remedial action in some instances.

A matrix dispersion based on phospholipid complex system: preparation, lymphatic transport, and pharmacokinetics

Raloxifene hydrochloride (RH) suffers from low oral bioavailability due to its low water-solubility and first-pass metabolism. Therefore, a novel phospholipid complex of RH (RHPC) and a matrix dispersion based on phospholipid complex (RHPC-MD) were successfully prepared and optimized. Several methods were used to validate the formation of RHPC and RHPC-MD, such as differential scanning calorimetry, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, infrared spectroscopy, particle size, and zeta potential, meanwhile, their octanol–water partition coefficient, solubility, and dissolution in vitro were also evaluated. To investigate the absorption mechanism of RHPC in vivo, the RHPC was administered to the chylomicron flow blockage rat model. Interestingly, as we expected, a significant reduction in RHPC absorption (67%) (**p< .01) in presence of cycloheximide (CXI) inhibitor was observed, thus confirming the RHPC could be absorbed by lymphatic transport in vivo. Pharmacokinetic studies revealed that the relative oral bioavailability of RHPC as well as RHPC-MD was 223% and 329%, respectively, when comparing with the commercial RH tablets. These outcomes suggested that the current study provided an attractive formulation to enhance the oral bioavailability of RH and stimulated to further research the absorption mechanism of RHPC in vivo.

Preparation and optimization of nilotinib self-micro-emulsifying drug delivery systems to enhance oral bioavailability

Objective: The objective of the current research was to prepare self-micro-emulsifying drug delivery systems (SMEDDS) for BCS class II drug, nilotinib to enhance its oral bioavailability. Methodology: Different types of excipients like oil, surfactant, and co-surfactant were evaluated for drug solubility. Among the screened excipients, Capryol 90, Transcutol HP, and Tween 80 were selected as oil, co-surfactant, and surfactant, respectively, to construct a ternary phase diagram to identify a homogenous mixture. Characterization performed for the prepared SMEDDS for its particle size/droplet size, emulsification time, phase separation, droplet morphology, in vitro drug release, and oral bioavailability. Results: Prepared SMEDDS showed the highest of 87% drug release in in vitro drug release experiment. SMEDDS drug release was superior over suspension formulation, which could be attributed to oil/surfactant ratios and particle size of the SMEDDS. The acquired pharmacokinetic parameters indicate that twofold increase in systemic exposure of SMEDDS compared with nilotinib suspension formulation. A similar twofold increase in relative oral bioavailability was also observed when compared SMEDDS formulation with suspension formulation. Delayed T max (time to reach peak plasma concentrations) was observed with SMEDDS over suspension formulation, which was evident by slow rate of absorption of nilotinib from SMEDDS. Conclusion: This research demonstrated that SMEDDS could be an effective approach to improve solubility and oral bioavailability for the BCS class II poorly soluble nilotinib.

Flash Fabrication of Orally Targeted Nanocomplexes for Improved Transport of Salmon Calcitonin across the Intestine.

Salmon calcitonin (sCT) is a potent calcium-regulating peptide hormone and widely applied for the treatment of some bone diseases clinically. However, the therapeutic usefulness of sCT is hindered by the frequent injection required, owing to its short plasma half-life and therapeutic need for a high dose. Oral delivery is a popular modality of administration for patients because of its convenience to self-administration and high patient compliance, while orally administered sCT remains a great challenge currently due to the existence of multiple barriers in the gastrointestinal (GI) tract. Here, we introduced an orally targeted delivery system to increase the transport of sCT across the intestine through both the paracellular permeation route and the bile acid pathway. In this system, sCT-based glycol chitosan-taurocholic acid conjugate (GC-T)/dextran sulfate (DS) ternary nanocomplexes (NC-T) were produced by a flash nanocomplexation (FNC) process in a kinetically controlled mode. The optimized NC-T exhibited well-controlled properties with a uniform and sub-60 nm hydrodynamic diameter, high batch-to-batch reproducibility, good physical or chemical stability, as well as sustained drug release behaviors. The studies revealed that NC-T could effectively improve the intestinal uptake and permeability, owing to its surface functionalization with the taurocholic acid ligand. In the rat model, orally administered NC-T showed an obvious hypocalcemia effect and a relative oral bioavailability of 10.9%. An in vivo assay also demonstrated that NC-T induced no observable side effect after long-term oral administration. As a result, the orally targeted nanocomplex might be a promising candidate for improving the oral transport of therapeutic peptides.

Synthesis, Characterization, and Pharmacodynamics Study of Enrofloxacin Mesylate.

IntroductionEnrofloxacin is used in the treatment of a wide variety of bacterial infections in mammals. However, its poor solubility limits the clinical use.MethodsIn order to improve the solubility of enrofloxacin, the enrofloxacin mesylate (EM) were obtained by a chemical synthesis method. The characterization of EM was carried out using ultraviolet scan (UV), synchronous thermal analysis (SDT), fourier transform infrared spectrometer (FTIR) and mass spectrometry (MS), nuclear magnetic resonance (NMR) and X-ray powder diffraction analysis (XRPD). Acute toxicity of EM in Kunming mice was studied. Besides, pharmacokinetic studies were performed in New Zealand rabbits at a single oral dose of 10 mg/kg, and the antibacterial activity of EM was also evaluated.ResultsEM was successfully synthesized and purified. The stoichiometric ratio of mesylate to enrofloxacin was 1:1 and the aqueous solubility of EM was 483.01±4.06 mg/mL, the solubility of EM was about 2000 times higher than enrofloxacin. The oral lethal dose (LD50) of EM was 1168.364 mg/kg, and the pharmacokinetics indicated that the oral relative bioavailability of EM was about 1.79 times and 1.48 times higher than that of enrofloxacin and enrofloxacin hydrochloride, respectively. In addition, the in vitro antibacterial activity of EM was not significantly changed compared with enrofloxacin and enrofloxacin hydrochloride.ConclusionEM has higher solubility, low toxicity for oral use, and increases the oral bioavailability in rabbit. This study may be of benefit for the development of new enrofloxacin drugs.

Effect of a Solid Lipid Nanoparticle Formulation on the Bioavailability of 4-(N)-Docosahexaenoyl 2', 2'-Difluorodeoxycytidine After Oral Administration.

Previously, we developed a solid lipid nanoparticle (SLN) formulation of 4-(N)-docosahexaenoyl 2', 2'-difluorodeoxycytidine (DHA-dFdC), a compound with promising antitumor activity. Herein, we studied the feasibility of administering the DHA-dFdC by the oral route using the solid lipid nanoparticles (i.e., DHA-dFdC-SLNs). In simulated gastrointestinal fluids, the DHA-dFdC-SLNs did not aggregate. The release of the DHA-dFdC from the solid lipid nanoparticles in simulated gastrointestinal fluid was slow, but was slightly faster in simulated intestinal fluid than in simulated gastric fluid. In mice orally administered with DHA-dFdC-SLNs, plasma DHA-dFdC concentration vs. time curve has a Tmax of ~ 1.7h and a Cmax of 17.01μg/mL. The absolute oral bioavailability of DHA-dFdC when given as DHA-dFdC-SLNs was ~ 68% (based on AUC0-24 h values), while the relative oral bioavailability DHA-dFdC (compared with DHA-dFdC in a Tween 80/ethanol-in-water solution) was 126%. Finally, in mice with pre-establish B16-F10 murine melanoma, oral DHA-dFdC-SLNs increased their survival significantly, as compared with oral administration of the DHA-dFdC solution. It is concluded that the solid lipid nanoparticle formulation increased the bioavailability of the DHA-dFdC upon oral administration, as compared with the DHA-dFdC solution.

Preparation of Ergosterol-Loaded Nanostructured Lipid Carriers for Enhancing Oral Bioavailability and Antidiabetic Nephropathy Effects.

In our previously studies, we confirmed that ergosterol could ameliorate diabetic nephropathy by suppressing the proliferation of mesangial cells and the accumulation of extracellular matrix (ECM). However, the therapeutic application of ergosterol may be confined due to poor aqueous solubility and low oral bioavailability. We aim to prepare ergosterol-loaded nanostructured lipid carriers (ERG-NLCs) to enhance the solubility and oral bioavailability of ergosterol. ERG-NLCs were prepared using glyceryl monostearate and decanoyl/octanoyl-glycerides by hot emulsification-ultrasonication method and characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD) analysis, entrapment efficiency (EE), and drug loading (DL) capacity studies. The prepared ERG-NLCs were spherical, with particle size of 81.39nm and negative zeta potential of 30.77mV. Ergosterol was successfully encapsulated in NLCs with a high EE of 92.95% and a DL capacity of 6.51%. In pharmacokinetic study, Cmax and AUC0-∞ of ergosterol in ERG-NLCs were obviously enhanced, and the relative oral bioavailability of ERG-NLCs was 277.56% higher than that of raw ergosterol. Moreover, the in vitro pharmacodynamic study indicated that ERG-NLCs inhibited high-glucose-stimulated mesangial cells over proliferation and ECM accumulation more effectively compared to raw ergosterol. In conclusion, the validated ERG-NLCs showed that NLCs mediated delivery could be used as potential vehicle to enhance solubility, oral bioavailability and therapeutic efficacy of ergosterol.

Synthesis of Tilmicosin Nanostructured Lipid Carriers for Improved Oral Delivery in Broilers: Physiochemical Characterization and Cellular Permeation.

This study aimed to develop nanostructured lipid carriers (NLCs) for improved oral absorption of tilmicosin (TMS) in broilers. Thus, palmitic acid, lauric acid, and stearic acid were selected as solid lipids to formulate TMS-pNLCs, TMS-lNLCs, and TMS-sNLCs, respectively. They showed similar physicochemical properties and meanwhile possessed excellent storage and gastrointestinal stability. The TMS interacted with the lipid matrix and was encapsulated efficiently in NLCs in an amorphous structure. NLCs could enhance oral absorption of TMS compared to 10% tilmicosin phosphate solution in broilers, among which the TMS-sNLCs were the most efficient drug delivery carriers, with a relative oral bioavailability of 203.55%. NLCs could inhibit the efflux of P-glycoprotein (P-pg) toward TMS, which may be involved with improved oral absorption. Taken together, these types of solid lipids influenced the enhanced level of NLCs toward oral bioavailability of TMS, and the sNLCs proved to be the most promising oral delivery carriers of TMS.

Pharmacokinetics of thalidomide in dogs: can feeding affect it? A preliminary study.

BackgroundTumor-associated neoangiogenesis is a crucial target for antitumor therapies. Thalidomide (TAL) is a promising anti-neoangiogenetic drug that has recently been used in the treatment of several malignancies in dogs.ObjectivesThe aim of the study was to assess the pharmacokinetics of TAL after single oral administration in dogs. Additionally, the influence of feeding on the pharmacokinetic profile of TAL in dogs has been preliminarily investigated.MethodsSix healthy adult female Labradors were enrolled according to a randomized single-dose, 2-treatment, 2-phase, paired 2 × 2 cross-over study design. The dogs were administered a single 400 mg capsule of TAL in fasted and fed conditions. Blood was collected from 15 min to 48 h after dosing, and TAL quantified in plasma by a validated high-performance liquid chromatography method. The pharmacokinetics of TAL were analyzed using a non-compartmental approach.ResultsTAL concentration was quantifiable up to 10 h and 24 h after fasted and fed conditions, respectively. Cmax (fasted, 1.34 ± 0.12 µg/mL; fed, 2.47 ± 0.19 µg/mL) and Tmax (fasted, 3 h; fed, 10 h) differed substantially between the 2 groups. AUC and t1/2λz were significantly higher in fed (42.46 ± 6.64 mg × h/L; 17.14 ± 4.68 h) compared to fasted (12.38 ± 1.13 mg × h/L; 6.55 ± 1.25 h) dogs. The relative oral bioavailability of TAL for the fasted group was low (36.92% ± 3.28%).ConclusionsFeeding affects the pharmacokinetics of oral TAL in dogs, showing a delayed, but higher absorption with different rate of elimination. These findings are of importance in clinical veterinary settings, and represent a starting point for further related studies.

Spray-Dried Silica Xerogel Nanoparticles as a Promising Gastroretentive Carrier System for the Management of Chemotherapy-Induced Nausea and Vomiting.

PurposeThe current work aimed to develop spray-dried silica xerogel nanoparticles (SXNs) as a gastroretentive carrier for the dual delivery of chlorambucil (CHL) and granisetron hydrochloride (GR). As a low-density system, it was proposed to float over gastric fluids; allowing for the retention of CHL in the acidic medium where it is more stable while ensuring the solubility of GR.MethodsSilica xerogels were developed by sol-gel process, using Tetraethyl orthosilicate (TEOS) water and acetic acid, followed by spray drying. SXNs were evaluated for particle size, zeta potential, entrapment efficiency (EE%), CHL and GR release after 1 hr (P1h) and after 8 hrs (P8h). The best achieved system (SXN4) was evaluated for morphology, pore diameter, total porosity, bulk density, wetting time, floating characteristics. Furthermore, the pharmacokinetics of the loaded drugs were evaluated in rats; relative to an aqueous CHL suspension containing GR.ResultsSXN4 system had the highest desirability (0.69); showing spherical nanoparticles (181.63 nm), negative zeta potential (−5.18 mV), promising EE% of 59.39% and 73.94% (for CHL and GR, respectively) and sustained CHL and GR release profiles characterized by low P1h (22.75% and 30.74%) and high P8h (60.36% and 99.33%), respectively. It had a mean pore diameter of 8.622 nm, a total porosity of 62.27%, a bulk density of 0.605 g/mL, a wetting time of 292 sec, zero lag time and a floating duration of at least 8 h.ConclusionThe prolongation in the mean residence time (MRT(0-∞)) and the promotion of the relative oral bioavailabilities of both drugs could unravel the potential of this system for the management of chemotherapy-induced nausea and vomiting.

Enlarged Pore Size Chiral Mesoporous Silica Nanoparticles Loaded Poorly Water-Soluble Drug Perform Superior Delivery Effect.

Large mesopores of chiral silica nanoparticles applied as drug carrier are worth studying. In this study, chiral mesoporous silica nanoparticles (CMSN) and enlarged chiral mesoporous silica nanoparticles (E-CMSN) with a particle size from 200 to 300 nm were synthesized. Fourier transform infrared spectrometer (FTIR), circular dichroism spectrum, scanning electron microscopy (SEM), transmission electron microscope (TEM), and nitrogen adsorption/desorption measurement were adopted to explore their characteristics. The results showed that the surface area, pore volume, and pore diameter of E-CMSN were higher than those of CMSN due to enlarged mesopores. Poorly water-soluble drug nimesulide (NMS) was taken as the model drug and loaded into carriers using adsorption method. After NMS was loaded into CMSN and E-CMSN, most crystalline NMS converted to amorphous phase and E-CMSN was superior. The anti-inflammatory pharmacodynamics and in vivo pharmacokinetics results were consistent with the wetting property and in vitro drug dissolution results, verifying that NMS/E-CMSN exhibited superior NMS delivery system based on its higher oral relative bioavailability and anti-inflammatory effect because its enlarge mesopores contributed to load and release more amorphous NMS. The minor variations in the synthesis process contributed to optimize the chiral nano-silica drug delivery system.

Nanoparticles from Gantrez® AN-poly(ethylene glycol) conjugates as carriers for oral delivery of docetaxel

The oral delivery of docetaxel (DTX) is challenging due to a low bioavailability, related to an important pre-systemic metabolism. With the aim of improving the bioavailability of this cytotoxic agent, nanoparticles from conjugates based on the copolymer of methyl vinyl ether and maleic anhydride (poly(anhydride)) and two different types of PEG, PEG2000 (PEG2) or methoxyPEG2000 (mPEG2), were evaluated. Nanoparticles, with a DTX loading close to 10%, were prepared by desolvation and stabilized with calcium, before purification and lyophilization. For the pharmacokinetic study, nanoparticles were orally administered to mice at a single dose of 30 mg/kg. The plasma levels of DTX were high, prolonged in time and, importantly, quantified within the therapeutic window. The relative oral bioavailability was calculated to be up to 56% when DTX was loaded in nanoparticles from poly(anhydride)-mPEG2000 conjugate (DTX-NP-mPEG2). Finally, a comparative toxicity study between equitoxic doses of free iv DTX and oral DTX-NP-mPEG2 was conducted in mice. Animals orally treated with DTX-loaded nanoparticles displayed less severe signs of hypersensitivity reactions, peripheral neurotoxicity, myelosuppression and hepatotoxicity than free iv docetaxel. In summary, poly(anhydride)-PEG conjugate nanoparticles appears to be adequate carries for the oral delivery of docetaxel.

Casein nanoparticles in combination with 2-hydroxypropyl-β-cyclodextrin improves the oral bioavailability of quercetin.

The aim of this work was to optimize the preparative process of quercetin loaded casein nanoparticles as well as to evaluate the pharmacokinetics of this flavonoid when administered orally in Wistar rats. Nanoparticles were obtained by coacervation after the incubation of casein, 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) and quercetin in an aqueous environment. Then, nanoparticles were purified and dried. The resulting nanoparticles displayed a size of 200 nm with a negative zeta potential and a payload of about 32 μg/mg. Release studies showed a zero-order kinetic, suggesting a mechanism based on erosion of the nanoparticle matrix. For the pharmacokinetic study, quercetin was orally administered to rats as a single dose of 25 mg/kg. Animals treated with quercetin-loaded casein nanoparticles displayed higher plasma levels than those observed in animals receiving the solution of the flavonoid (control). Thus, the relative oral bioavailability of quercetin when administered as casein nanoparticles (close to 37%) was found to be about 9-times higher than the oral solution of the flavonoid in a mixture of PEG 400 and water. In summary, the combination of casein and 2-hydroxypropyl-β-cyclodextrin produces nanoparticles that may be a good option to load quercetin for both nutraceutical and pharmaceutical purposes.

Preparation, characterization and pharmacokinetic evaluation of rosuvastatin calcium incorporated cyclodextrin-polyanhydride nanoparticles

Objective: The aim of the study was to formulate, cyclodextrin (CD)-polyanhydride (PA) nanoparticles (CPNs) with rosuvastatin calcium (RCa) in order to enhance the poor oral bioavailability.Methods: CPNs containing RCa/CD complexes were prepared by a modified solvent displacement method and morphological analyses, particle size (PS), polydispersity index (PDI), zeta potential (ZP), encapsulation efficiency (EE), DSC, FT-IR, XRD, 1H-NMR analyses were performed. In vitro release properties, release kinetics, cytotoxicity, in vitro permeability and pharmacokinetic studies were also studied. The stability of the formulations were evaluated during the storage period of 3 months.Results: The physicochemical studies showed that the RCa/CD complexes were well incorporated into CPNs resulted in nanosized particles (215.22 and 189.13 nm) with homogenous size distribution (PDI: 0.203 and 0.182) with relatively high incorporation capacity (76.11 and 68.18%) for the CPN1 and CPN2 formulations respectively. Sustained release of RCa from CPNs were achieved. The cytotoxicity values showed that the safety of the formulations. According to permeability studies, pure RCa had lowest permeability data (3.08 × 10−7 cm⋅s−1 Papp value) while CPNs gained higher permeability data (1.36 × 10−5 and 1.12 × 10−5 cm⋅s−1 Papp values) for the CPN1 and CPN2 formulations respectively. CPN2 formulation was selected for pharmacokinetic studies and analyses results demonstrated that approximately 8-fold relative oral bioavailability enhancement compared to the pure RCa was achieved.Conclusion: Considering the analyses results of the study, CPNs can be regarded as suitable, safe, functional oral delivery systems for RCa with enhanced oral bioavailability.

Novel cuminaldehyde self-emulsified nanoemulsion for enhanced antihepatotoxicity in carbon tetrachloride-treated mice

Cuminaldehyde self-emulsified nanoemulsion (CuA-SEN) was prepared and optimised to improve its oral bioavailability and antihepatotoxicity. Cuminaldehyde self-emulsified nanoemulsion was developed through the self-nanoemulsification method using Box-Behnken Design (BBD) tool while appropriate physicochemical indices were evaluated. The optimised CuA-SEN was characterised via droplet size (DS), morphology, polydispersity index (PDI), zeta potential (ZP), entrapment efficiency, in-vitro release, and pharmacokinetic studies while its antihepatotoxicity was evaluated. Cuminaldehyde self-emulsified nanoemulsion with acceptable characteristics (mean DS-48.83 ± 1.06 nm; PDI-0.232±0.140; ZP-29.92±1.66mV; EE-91.51±0.44%; and drug-loading capacity (DL)-9.77±0.75%) was formulated. In-vitro drug release of CuA-SEN significantly increased with an oral relative bioavailability of 171.02%. Oral administration of CuA-SEN to CCl4 -induced hepatotoxicity mice markedly increased the levels of superoxide dismutase, glutathione and catalase in serum. Also, CuA-SEN reduced the levels of tumour necrosis factor-alpha and interleukin-6 in both serum and liver tissues while aspartate aminotransferase, alanine aminotransferase and malonaldehyde levels were significantly decreased. These findings showed that the improved bioavailability of cuminaldehyde via SEN provided an effective approach for enhancing antioxidation, anti-inflammation and antihepatotoxicity of the drug.

Improved self-assembled micelles based on supercritical fluid technology as a novel oral delivery system for enhancing germacrone oral bioavailability.

The main objective of this study was to develop a novel self-assembled micelle system to improve the oral bioavailability of the water-insoluble and thermal instable germacrone (GEM). Micelles were prepared with an improved supercritical reverse phase evaporation (ISCRPE) method, and the thin-film hydration (TFH) method was used for comparison. Physicochemical characterization confirmed the nanospherical morphology of the micelles prepared by the ISCRPE method (GEM@SDL-SCF Micelles) had smaller particle size and greater encapsulation efficiency than that of the micelles prepared by the TFH method (GEM@SDL-THF Micelles). Dilution resistance and stability experiments were performed to assess the structural integrity. In vitro GEM release was analyzed by the dialysis diffusion method, and the micelle system showed sustained and cumulative release. Furthermore, the fluorescence results from the cellular uptake study revealed improved drug absorption of GEM since the green fluorescence intensity of C6@SDL-SCF Micelles were stronger than that of C6@SDL-TFH Micelles. The transcellular transport study showed a distinct increase in the apparent permeability coefficient (AP → BL) in a Caco-2 cell transport model, and free GEM solution, GEM@SDL-TFH Micelles and GEM@SDL-SCF Micelles had permeability coefficients of 7.30 × 10-6, 8.01 × 10-6, and 10.57 × 10-6 cm·s-1, respectively. The pharmacokinetics study in Sprague-Dawley rats showed that the oral absorption capacity of the GEM@SDL-SCF Micelles was obviously enhanced, with a relative oral bioavailability of 298% and 147% compared with that of free GEM solution and GEM@SDL-TFH Micelles, respectively. The gastrointestinal safety assessment demonstrated that the micelles used in the experiment did not cause gastrointestinal toxicity. These results indicated that self-assembled micelles are promising nanocarriers aimed at enhancing the oral absorption of drugs with thermal sensitivity and low aqueous solubility, and micelles prepared by supercritical fluid (SCF) technology showed better performance than those prepared by the TFH method.

Rapamycin loaded TPGS-Lecithins-Zein nanoparticles based on core-shell structure for oral drug administration.

Rapamycin as a novel macrolide immunosuppressive agent has been commonly used in organ transplantation owing to its stronger immunosuppressive effect, non-nephrotoxicity and lower side effect. However its drawbacks of low bioavailability and big individual difference remain to be improved in clinical application. Here rapamycin loaded TPGS-Lecithins-Zein nanoparticles (RTLZ-NPs) with core-shell structure were prepared by the phase separation method. The RTLZ-NPs were approximately 190.3 nm in size, with PDI and zeta potential about 0.256 and -19.71 mV respectively. Drug entrapment and loading achieved were about 86.64 and 25.73% respectively. Meanwhile RTLZ-NPs exhibited favorable enzymolysis resistance abilities in gastrointestinal environments and enhanced uptake in Caco-2 cells. The optimum absorption sites of rapamycin in the intestine were duodenum and jejunum as single-pass intestinal perfusion assay. Upon also considering the results of Caco-2 cell assay, it could be speculated that the transport of rapamycin in vivo involved active transport as well as P-glycoprotein (P-gp) based efflux. Finally, the relative oral bioavailability of RTLZ-NPS was 4.33 fold higher than free rapamycin in SD rat. Altogether the designed nanoparticles can be an efficient oral delivery strategy for rapamycin analogues to prevent the attacks from destructive enzymes, reduce cell efflux, increase cell uptake, and then enhance the oral bioavailability.