Design of PEG-grafted-PLA nanoparticles as oral permeability enhancer for P-gp substrate drug model Famotidine

Bioavailability of oral drugs can be limited by an intestinal excretion process mediated by P-glycoprotein (P-gp). Polyethylene glycol (PEG) is a known P-gp inhibitor. Dispersion of Famotidine (a P-gp substrate) within PEGylated nanoparticles (NPs) was used to improve its oral bioavailability. In this work, we evaluated the potential impact of NPs prepared from a grafted copolymer of polylactic acid and PEG on P-gp function by studying in vitro permeability of Famotidine across Caco-2 cells. Copolymers of PEG grafted on polylactic acid (PLA) backbone (PLA-g-PEG) were synthesised with 1?mol% and 5?mol% PEG vs. lactic acid monomer using PEG 750 and 2000?Da. The polymers were used to prepare Famotidine-loaded NPs and tested in vitro on Caco-2 cells. Significant decrease in basolateral-to-apical transport of Famotidine was observed when Famotidine was encapsulated in NPs prepared from PLA-g-PEG5%. NPs prepared from PLA-g-PEG5% are promising to improve oral bioavailability of P-gp substrates.     

Iron casein succinylate-chitosan coacervate for the liquid oral delivery of iron with bioavailability and stability enhancement

Iron casein succinylate (ICS) liquid oral preparation as iron supplement has uncomfortable taste after a long period of storage because of its stability, and poor bioavailability of iron compared to any other iron preparations. To improve the chemical stability of ICS and enhance the bioavailability of iron, chitosan-ICS nanoparticles (NPs) were prepared by complex coacervation method and stabilized with polyethylene glycol (PEG) 400. NPs were spherical (mean diameter of 830–1070 nm) with positive charge (+30–60 mV) depending on the composition of NPs. Addition of PEG400 (2 w/v %) increased the zeta potential (26–50 %) and physical stability of chitosan-ICS NPs suspension. Also, NPs decreased iron release compared to ICS after 7-weeks of storage at 4 °C. NPs markedly increased the permeability of iron in Caco-2 cell up to 32–38-fold compared to ICS, while physical mixture of chitosan and ICS increased the iron permeability only 2.5-fold. In summary, NPs improved the physicochemical stability and enhanced the transport of iron compared to other iron preparations in Caco-2 cell model. Thus, chitosan-ICS coacervate might be a promising candidate as a liquid oral iron delivery system for iron deficiency patients with stability and bioavailability enhancement.     

PEG–lipid–PLGA hybrid nanoparticles loaded with berberine–phospholipid complex to facilitate the oral delivery efficiency

The natural product berberine (BBR), present in various plants, arouses great interests because of its numerous pharmacological effects. However, the further development and application of BBR had been hampered by its poor oral bioavailability. In this work, we report on polymer–lipid hybrid nanoparticles (PEG–lipid–PLGA NPs) loaded with BBR phospholipid complex using a solvent evaporation method for enhancing the oral BBR efficiency. The advantage of this new drug delivery system is that the BBR–soybean phosphatidylcholine complex (BBR–SPC) could be used to enhance the liposolubility of BBR and improve the affinity with the biodegradable polymer to increase the drug-loading capacity and controlled/sustained release. The entrapment efficiency of the PEG–lipid–PLGA NPs/BBR–SPC was observed to approach approximately 89% which is more than 2.4 times compared with that of the PEG–lipid–PLGA NPs/BBR. To the best of our knowledge, this is the first report on using polymer material for effective encapsulation of BBR to improve its oral bioavailability. The prepared BBR delivery systems demonstrated a uniform spherical shape, a well-dispersed core-shell structure and a small particle size (149.6?±?5.1?nm). The crystallographic and thermal analysis has indicated that the BBR dispersed in the PEG–lipid–PLGA NPs matrix is in an amorphous form. More importantly, the enhancement in the oral relative bioavailability of the PEG–lipid–PLGA NPs/BBR–SPC was ～343% compared with that of BBR. These positive results demonstrated that PEG–lipid–PLGA NPs/BBR–SPC may have the potential for facilitating the oral drug delivery of BBR.     

Enhanced Oral Paclitaxel Bioavailability After Administration of Paclitaxel-Loaded Lipid Nanocapsules

Purpose The aim of this study was to evaluate the pharmacokinetics of paclitaxel-loaded lipid nanocapsules (LNC) in rats to assess the intrinsic effect of the dosage form on the improvement of paclitaxel oral exposure. Methods Paclitaxel-loaded LNC were prepared and characterized in terms of size distribution, drug payload, and the kinetics of paclitaxel crystallization. Taxol?, Taxol? with verapamil, or paclitaxel-loaded LNC were administered orally to rats. The plasma concentration of paclitaxel was determined using liquid chromatography mass spectrometry. Results The average size of LNC was 60.9 ± 1.5 nm. The drug payload of paclitaxel was 1.91 ± 0.01 mg/g of aqueous dispersion. The encapsulation efficiency was 99.9 ± 1.0%, and 1.7 ± 0.1% of paclitaxel was crystallized after 24 h. The oral bioavailability of Taxol? alone was 6.5%. After oral administration of paclitaxel-loaded LNC or paclitaxel associated with verapamil, the area under the plasma concentration–time curve was significantly increased (about 3-fold) in comparison to the control group (p < 0.05). Conclusions The results indicated that LNC provided a promising new formulation to enhance the oral bioavailability of paclitaxel while avoiding the use of pharmacologically active P-gp inhibitors, such as verapamil.     

Dipeptide-modified nanoparticles to facilitate oral docetaxel delivery: new insights into PepT1-mediated targeting strategy

Oligopeptide transporter 1 (PepT1) has been a striking prodrug-designing target. However, the underlying mechanism of PepT1 as a target to facilitate the oral absorption of nanoparticles (NPs) remains unclear. Herein, we modify Poly (lactic-co-glycolic acid) (PLGA) NPs with the conjugates of dipeptides (L-valine-valine, L-valine-phenylalanine) and polyoxyethylene (PEG Mw: 1000, 2000) stearate to facilitate oral delivery of docetaxel (DTX) to investigate the oral absorption mechanism and regulatory effects on PepT1 of the dipeptide-modified NPs. The cellular uptake of the dipeptide-modified NPs is more efficient than that of the unmodified NPs in the stably transfected hPepT1- Hela cells and Caco-2 cells, suggesting the involvement of PepT1 in the endocytosis of NPs. The internalization of the dipeptide-modified NPs is proved to be a proton-dependent process. Moreover, the L-valine-valine modified NPs with shorter PEG chain exhibit distinct advantages in terms of intestinal permeability and oral absorption, resulting in significantly improved oral bioavailability of DTX. In summary, PepT1 could serve as a desirable target for oral nanoparticulate drug delivery and the dipeptide-modified NPs represent a promising nanoplatform to facilitate oral delivery of hydrophobic drugs with low bioavailability.     

Bioavailability enhancement of a poorly water-soluble drug by solid dispersion in polyethylene glycol-polysorbate 80 mixture

Oral bioavailability of a poorly water-soluble drug was greatly enhanced by using its solid dispersion in a surface-active carrier. The weakly basic drug (pK(a) approximately 5.5) had the highest solubility of 0.1mg/ml at pH 1.5, < 1 microg/ml aqueous solubility between pH 3.5 and 5.5 at 24+/-1 degrees C, and no detectable solubility (< 0.02 microg/ml) at pH greater than 5.5. Two solid dispersion formulations of the drug, one in Gelucire 44/14 and another one in a mixture of polyethylene glycol 3350 (PEG 3350) with polysorbate 80, were prepared by dissolving the drug in the molten carrier (65 degrees C) and filling the melt in hard gelatin capsules. From the two solid dispersion formulations, the PEG 3350-polysorbate 80 was selected for further development. The oral bioavailability of this formulation in dogs was compared with that of a capsule containing micronized drug blended with lactose and microcrystalline cellulose and a liquid solution in a mixture of PEG 400, polysorbate 80 and water. For intravenous administration, a solution in a mixture of propylene glycol, polysorbate 80 and water was used. Absolute oral bioavailability values from the capsule containing micronized drug, the capsule containing solid dispersion and the oral liquid were 1.7+/-1.0%, 35.8+/-5.2% and 59.6+/-21.4%, respectively. Thus, the solid dispersion provided a 21-fold increase in bioavailability of the drug as compared to the capsule containing micronized drug. A capsule formulation containing 25 mg of drug with a total fill weight of 600 mg was subsequently selected for further development. The selected solid dispersion formulation was physically and chemically stable under accelerated storage conditions for at least 6 months. It is hypothesized that polysorbate 80 ensures complete release of drug in a metastable finely dispersed state having a large surface area, which facilitates further solubilization by bile acids in the GI tract and the absorption into the enterocytes. Thus, the bioavailability of this poorly water-soluble drug was greatly enhanced by formulation as a solid dispersion in a surface-active carrier.     

Novel tablet formulation of amorphous candesartan cilexetil solid dispersions involving P-gp inhibition for optimal drug delivery: in vitro and in vivo evaluation

Objective: The aim of this study was to develop a novel tablet formulation of amorphous candesartan cilexetil (CAN) solid dispersion involving effective P-gp inhibition for optimal drug delivery by direct compression (DC) method.

Methods: To accomplish DC, formulation blends were evaluated for micromeritic properties. The Carr index, Hausner ratio, flow rate and cotangent of the angle α were determined. The tablets with and without naringin prepared by DC technique were evaluated for average weight, hardness, disintegration time and friability assessments. The drug release profiles were determined to study the dissolution kinetics. In vivo pharmacokinetic studies were conducted in rabbits. Accelerated stability studies were performed for tablets at 40?±?2?°C/75% RH?±?5% for 6 months.

Results: FTIR studies confirmed no discoloration, liquefaction and physical interaction between naringin and drug. The results indicated that tablets prepared from naringin presented a dramatic release (82%) in 30?min with a similarity factor (76.18), which is most likely due to the amorphous nature of drug and the higher micromeritic properties of blends. Our findings noticed 1.7-fold increase in oral bioavailability of tablet prepared from naringin with mean C_max and AUC_0–12?h values as 35.81?±?0.13?μg/mL and 0.14?±?0.09?μg h/mL, respectively. The tablets with and without naringin prepared by DC technique were physically and chemically stable under accelerated stability conditions upon storage for 6 months.

Conclusion: These results are attractive for further development of an oral tablet formulation of CAN through P-gp inhibition using naringin, a natural flavonoid as a pharmaceutical excipient.     

In vitro-in vivo evaluation of supercritical processed solid dispersions: permeability and viability assessment in Caco-2 cells

In this study improvement in the bioavailability of carbamazepine (CBZ) prepared as solid dispersions by conventional solvent evaporation and supercritical fluid (SCF) processing methods was assessed, along with the elucidation of the mechanism of improved absorption. Solid dispersions of CBZ in polyethylene glycol (PEG) with either Gelucire 44/14 or vitamin E-TPGS (TPGS) were evaluated by intrinsic dissolution. Directional transport through Caco-2 cell monolayers was determined in the presence and absence of TPGS. Cell viability in presence of various concentrations of amphiphilic carriers was seen. In vivo oral bioavailability was determined in rats. The apparent intrinsic dissolution rates (IDR) of both conventional- and SCF-CBZ/PEG 8000/TPGS solid dispersions were increased by 13- and 10.6-fold, respectively, relative to neat CBZ. CBZ was not a substrate of P-glycoprotein. Higher CBZ permeability was seen in presence of 0.1% TPGS. Cell viability studies showed significant cytotoxicity only at or above 0.1% amphiphilic carrier. Supercritical treated formulation (without amphiphilic carrier) displayed oral bioavailability on par with those conventional solid dispersions augmented with amphiphilic carriers. An in vitro-in vivo correlation was seen between IDR and the AUC of the various CBZ solid dispersions. Bioavailability of CBZ was more a function of dissolution as opposed to membrane effects. Although bioavailability from SCF processed dispersions was better than conventionally processed counterparts (except for one formulation containing Gelucire 44/14), an interaction of processing method and inclusion of an amphiphilic carrier, rather by one factor alone contributed to optimal absorption, thus giving contradictory results for Gelucire 44/14 and TPGS formulations.     

Preparation and evaluation of a microemulsion for oral delivery of berberine

The principal aim of this study was to develop an oral microemulsion formulation of berberine in order to improve its bioavailability. The Microemulsion was prepared with pharmaceutically acceptable ingredients such as oleic acid, Tween 80 and PEG400. Phase diagrams were drawn to elucidate the phase behavior of systems, which were composed of Tween 80 as surfactant and PEG400 as cosurfactant. A single isotropic region, considered to be a bicontinuous microemulsion, was detected in the pseudo ternary phase diagrams. The berberine-loaded microemulsion was characterized by viscosity, refractive index, electrical conductivity and particle size. In vivo pharmacokinetic profile and oral bioavailability were also investigated in rats. The optimized formulation was as follows: 15 wt.% oleic acid, 17 wt.% Tween-80, 17 wt.% PEG400, and 51 wt.% water. The formulated microemulsion was found to be relatively uniform in size (24.0 nm). The in vivo study indicated that the bioavailability of the oral berberine-loaded microemulsion formulation was 6.47 times greater than that of the berberine tablet suspensions. The results suggest that the microemulsion is a promising oral drug delivery system for berberine.     

Nanoparticle formulation of 11-keto-β-boswellic acid (KBA): anti-inflammatory activity and in vivo pharmacokinetics

Context: The oleo-gum-resin of Boswellia serrata Roxb. (Burseraceae) is widely used for the treatment of inflammatory diseases such as osteoarthritis, rheumatoid arthritis and cancer. Anti-inflammatory activity of 11-keto-β-boswellic acid (KBA) is impeded by poor oral bioavailability due to its high lipid solubility, rapid phase-1 metabolism and poor intestinal permeability.

Objective: This study developed a poly-dl-lactide-co-glycolide-based nanoparticle formulation of KBA to improve its oral bioavailability and in vivo anti-inflammatory activity.

Materials and methods: KBA was isolated from the oleo-gum resin of B. serrata, and its nanoparticle formulation (KBA-NPs) was prepared by the emulsion–diffusion–evaporation method. Oral bioavailability of KBA and KBA-NPs was studied at 50?mg/kg p.o. dose in Sprague–Dawley rats, and further evaluated for in vivo anti-inflammatory activity in carrageenan-induced rat paw oedema assay at the same dose level.

Results: The prepared KBA-NPs had a particle size of 152.6?nm with polydispersity index of 0.194, 79.7% entrapment efficiency and a cumulative 61.5% release of KBA from KBA-NPs, at 72?h. KBA-NPs showed 60.8% inhibition of rat paw oedema at 5?h as compared to 34.9% as that of KBA. The results of oral bioavailability study and in vivo anti-inflammatory activity showed 7- and 1.7-fold increase in bioavailability and anti-inflammatory activity, respectively, of KBA in KBA-NPs as compared to KBA alone.

Conclusion: The results of improved oral bioavailability and in vivo anti-inflammatory activity of KBA-NPs suggested successful development of KBA nanoparticle formulation.     

Atazanavir-loaded Eudragit RL 100 nanoparticles to improve oral bioavailability: optimization and in vitro/in vivo appraisal

Abstract

Atazanavir (ATV) is a HIV protease inhibitor. Due to its intense lipophilicity, the oral delivery of ATV encounters several problems such as poor aqueous solubility, pH-dependent dissolution, rapid first-pass metabolism in liver by CYP3A5, which result in low bioavailability. To overcome afore mentioned limitations, ATV-loaded Eudragit RL100 nanoparticles (ATV NPs) were prepared to enhance oral bioavailability. ATV NPs were prepared by nanoprecipitation method. The ATV NPs were systematically optimized (OPT) using 3² central composite design (CCD) and the OPT formulation located using overlay plot. The pharmacokinetic study of OPT formulation was investigated in male Wistar rats, and in-vitro/in-vivo correlation level was established. Intestinal permeability of OPT formulation was determined using in situ single pass perfusion (SPIP) technique. Transmission electron microscopy studies on OPT formulation demonstrated uniform shape and size of particles. Augmentation in the values of K_a (2.35-fold) and AUC_0-24 (2.91-fold) indicated significant enhancement in the rate and extent of bioavailability by the OPT formulation compared to pure drug. Successful establishment of in vitro/in vivo correlation (IVIVC) Level A substantiated the judicious choice of the in vitro dissolution milieu for simulating the in vivo conditions. In situ SPIP studies ascribed the significant enhancement in absorptivity and permeability parameters of OPT formulation transport through the Peyer's patches. The studies, therefore, indicate the successful formulation development of NPs with distinctly improved bioavailability potential and can be used as drug carrier for sustained or prolonged drug release.     

Oral administration of amphotericin B nanoparticles: antifungal activity,bioavailability and toxicity in rats

Amphotericin B (AMB) is used most commonly in severe systemic life-threatening fungal infections. There is currently an unmet need for an efficacious (AMB) formulation amenable to oral administration with better bioavailability and lower nephrotoxicity. Novel PEGylated polylactic-polyglycolic acid copolymer (PLGA-PEG) nanoparticles (NPs) formulations of AMB were therefore studied for their ability to kill Candida albicans (C. albicans). The antifungal activity of AMB formulations was assessed in C. albicans. Its bioavalability was investigated in nine groups of rats (n?=?6). Toxicity was examined by an in vitro blood hemolysis assay, and in vivo nephrotoxicity after single and multiple dosing for a week by blood urea nitrogen (BUN) and plasma creatinine (PCr) measurements. The MIC of AMB loaded to PLGA-PEG NPs against C. albicans was reduced two to threefold compared with free AMB. Novel oral AMB delivery loaded to PLGA-PEG NPs was markedly systemically available compared to Fungizone® in rats. The addition of 2% of GA to the AMB formulation significantly (p??790% that of Fungizone®. The novel AMB formulations showed minimal toxicity and better efficacy compared to Fungizone®. No nephrotoxicity in rats was detected after a week of multiple dosing of AMB NPs based on BUN and PCr, which remained at normal levels. An oral delivery system of AMB-loaded to PLGA-PEG NPs with better efficacy and minimal toxicity was formulated. The addition of glycyrrhizic acid (GA) to AMB NPs formulation resulted in a significant oral absorption and improved bioavailability in rats.     

Enhanced Oral Bioavailability of Paclitaxel Formulated in Vitamin E-TPGS Emulsified Nanoparticles of Biodegradable Polymers: In Vitro and In Vivo Studies

This work evaluates the effects of paclitaxel loaded polymeric nanoparticles (NPs) composed of poly(D,L-lactic-co-glycolic acid) (PLGA) with vitamin E TPGS as emulsifier for oral chemotherapy. NPs prepared by a modified solvent extraction/evaporation technique were observed in spherical shape of 200-300 nm diameter with a high drug encapsulation efficiency (EE) of 80.9%. The TPGS-emulsified PLGA NPs formulation of paclitaxel was found of great advantages over that of Taxol®. The in vitro viability experiment showed that the NP formulation could be 1.28,1.38,1.12 times more effective than Taxol® after 24, 48, 72 h incubation with MCF-7 human breast cancer cell line at 2.5 μg/mL paclitaxel concentration. In vivo evaluation confirmed the advantages of the TPGS-emulsified PLGA NP formulation versus Taxol® in promoting oral bioavailability of paclitaxel. Such a NP formulation achieved more than 10 times higher oral bioavailability than Taxol®, which resulted 9.74-fold higher therapeutic effect and 12.56-fold longer sustainable therapeutic time than Taxol®. The present proof-of-concept experimental data proved that the formulation of vitamin E TPGS emulsified PLGA NPs is a promising approach for paclitaxel oral administration. Oral chemotherapy by NPs formulation is feasible. © 2010 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 99:3552-3560, 2010     

法莫替丁泡腾片的制备与质量考察

目的研制法莫替丁泡腾片并建立质量控制方法。方法单因素筛选处方,粉末直接压片制备法莫替丁泡腾片,并对其性状、重量差异、崩解时限、酸度、含量等进行检查。结果确定了泡腾片的处方,即酒石酸-碳酸氢钠=1∶1,崩解剂用量为60%,乳糖为填充剂,润滑剂为PEG6000 3%,硬脂酸镁0.3%,本品在5 min内可完全崩解。结论本品处方合理,制备工艺简单,可进行推广开发。     

Pre-clinical and clinical evaluation of solution and soft gelatin capsule formulations for a BCS class 3 compound with atypical physicochemical properties

R1481 is a sub-type selective muscarinic receptor antagonist with the potential treatment of overactive bladder. R1481 presents two challenges for drug development. The first is the viscous semi-solid nature of the active pharmaceutical ingredient (API). The second challenge is the poor oral bioavailability of this water soluble, metabolically stable compound due to low intestinal permeability, and the P-glycoprotein (P-gp) efflux mechanism. Vitamin E TPGS is reported by others to enhance bioavailability by increasing the solubility of active compounds and by inhibiting P-gp in the intestine. In this report, compatibility of R1481 in Capmul MCM-based formulations with and without vitamin E TPGS is summarized. Review of accelerated stability studies of oral formulations led to the identification of a soft gelatin capsule formulation using neat Capmul MCM as an acceptable formulation for Phase 1 clinical studies. Soft gelatin capsules (5 mg strength) were manufactured with and without the addition of vitamin E TPGS. Clinical data show that vitamin E TPGS does not improve systemic exposure of R1481 in humans.     

Development of mucoadhesive floating hollow beads of acyclovir with gastroretentive properties

Abstract

This study aimed at improving the oral bioavailability of acyclovir (ACV) through incorporating it into gastroretentive dosage form based on floating hollow chitosan beads. Hollow chitosan beads were prepared using a solvent free, ionotropic gelation method. The effect of formulation parameters, including chitosan molecular weight and drug concentration, on bead characteristics was studied. The drug containing formulations had yields >70.5?±?0.31%. The entrapment efficiencies for the medium molecular weight chitosan formulations (56.29?±?0.94%–62.75?±?0.86%) was greater than the high molecular weight chitosan formulation (29.21?±?0.89%). The density of all formulations was below that of gastric fluid, the greatest density observed was 0.60?±?0.01?g?cm^?3. Unsurprisingly, the formulations were immediate bouyant to different degrees in both pH 1.2 and pH 6.8 media. In addition, the chitosan beads were all seen to swell in pH 1.2 media and demonstrated mucoadhesive properties. A sustained release profile was observed from the chitosan beads, the developed formulations released drug at slower rates than a marketed ACV oral tablet. The developed system has the dual advantages of being gastroretentive, to increase oral bioavailability and releasing drug in a controlled manner, to reduce the required frequency of administration thereby promoting patient adherence.     

Bioavailability enhancement,Caco-2 cells uptake and intestinal transport of orally administered lopinavir-loaded PLGA nanoparticles

Nanoparticles (NPs) can be absorbed via M cells of Peyer’s patches after oral delivery leading to passive lymphatic targeting followed by systemic drug delivery. Hence, the study was aimed to formulate PLGA NPs of lopinavir. The NPs were prepared by nanoprecipitation, optimized by 3³ factorial design and characterized by TEM, DSC, FTIR studies and safety was assessed by MTT assay. In vivo pharmacokinetic studies were performed in rats. The NPs were discrete spherical structures having particle size of 142.1?±?2.13?nm and entrapment of 93.03?±?1.27%. There was absence of drug-polymer interaction. Confocal images revealed the penetration and absorption of coumarin-loaded NPs in Caco-2 cells and intestine after oral delivery. There was 3.04 folds permeability and 13.9 folds bioavailability enhancement from NPs. The NPs can be promising delivery system for antiretroviral drug by delivering the drug to lymph (major HIV reservoir site) via direct absorption through intestine before reaching systemic circulation.     

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

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

PLGA nanoparticles for the oral delivery of nuciferine: preparation,physicochemical characterization and in vitro/in vivo studies

This article reports a promising approach to enhance the oral delivery of nuciferine (NUC), improve its aqueous solubility and bioavailability, and allow its controlled release as well as inhibiting lipid accumulation. NUC-loaded poly lactic-co-glycolic acid nanoparticles (NUC-PLGA-NPs) were prepared according to a solid/oil/water (s/o/w) emulsion technique due to the water-insolubility of NUC. PLGA exhibited excellent loading capacity for NUC with adjustable dosing ratios. The drug loading and encapsulation efficiency of optimized formulation were 8.89?±?0.71 and 88.54?±?7.08%, respectively. NUC-PLGA-NPs exhibited a spherical morphology with average size of 150.83?±?5.72?nm and negative charge of ?22.73?±?1.63?mV, which are suitable for oral administration. A sustained NUC released from NUC-PLGA-NPs with an initial exponential release owing to the surface associated drug followed by a slower release of NUC, which was entrapped in the core. In addition, ～77?±?6.67% was released in simulating intestinal juice, while only about 45.95?±?5.2% in simulating gastric juice. NUC-PLGA-NPs are more efficient against oleic acid (OA)-induced hepatic steatosis in HepG₂ cells when compared to naked NUC (n-NUC, *p < 0.05). The oral bioavailability of NUC-PLGA-NPs group was significantly higher (**p < 0.01) and a significantly decreased serum levels of total cholesterol (TC), triglycerides (TG) and low-density lipoprotein cholesterol (LDL-C), as well as a higher concentration of high-density lipoprotein cholesterol (HDL-C) was observed, compared with that of n-NUC treated group. These findings suggest that NUC-PLGA-NPs hold great promise for sustained and controlled drug delivery with improved bioavailability to alleviating lipogenesis.     

Involvement of P-glycoprotein,Multidrug Resistance Protein 2 and Breast Cancer Resistance Protein in the Transport of Belotecan and Topotecan in Caco-2 and MDCKII Cells

Purpose  To investigate the underlying mechanism of low bioavailabilities of the water-soluble camptothecin derivatives, belotecan and topotecan. Methods  The bioavailability of belotecan and topotecan in rats was determined following oral administration of each drug at a dose of 5 mg/kg body weight. The vectorial transport of each drug was measured in Caco-2 and engineered MDCK II cells. Results  The bioavailability of belotecan (11.4%) and topotecan (32.0%) in rats was increased to 61.5% and 40.8%, respectively, by the preadministration of CsA at a dose of 40 mg/kg. Contrary to the absorptive transport, the secretory transport of these drugs across the Caco-2 cell monolayer was concentration-dependent, saturable, and significantly inhibited by the cis presence of verapamil (a P-gp substrate), MK-571 (an MRP inhibitor), bromosulfophthalein (BSP, an MRP2 inhibitor), fumitremorgin C (FTC, a BCRP inhibitor) and cyclosporine A (CsA, an inhibitor of P-gp and BCRP, and a substrate of P-gp) suggesting the involvement of these transporters, which could be further confirmed in MDCKII/P-gp, MDCKII/MRP2 and MDCKII/BCRP cells. Conclusion  The involvement of secretory transporters P-gp, MRP2 and BCRP, particularly for belotecan, as well as a low passive permeability, appears to be responsible for the low bioavailability of belotecan and topotecan. Hong Li and Hyo-Eon Jin have contributed equally to this work.