The contribution of absorption of integral nanocrystals to enhancement of oral bioavailability of quercetin

In this study,self-discriminating hybrid nanocrystals was utilized to explore the biological fate of quercetin hybrid nanocrystals(QT-HNCs)with diameter around 280 nm(QT-HNCs-280)and550 nm(QT-HNCs-550)following oral and intravenous administration and the contribution of integral nanocrystals to oral bioavailability enhancement of QT was estimated by comparing the absolute exposure of integral QT-HNCs and total QT in the liver.Results showed that QT-HNCs could reside in vivo as intact nanocrystals for as long as 48 h following oral and intravenous administration.A higher accumulation of integral QT-HNCs in liver and lung was observed for both oral and intravenous administration of QT-HNCs.The particle size affects the absorption and biodistribution of integral QT-HNCs and total QT.As compared to QT-HNCs-550,QT-HNCs-280 with smaller particle size is more easily absorbed,but dissolves faster in vivo,leading to higher distribution of QT(146.90 vs.117.91 h·mg/mL)but lower accumulation of integral nanocrystals(6.82 e10 vs.15.27 e10 h·[p/s]/[μW/cm2])in liver following oral administration.Due to its slower dissolution and enhanced recognition by RES,QT-HNCs-550 with larger diameter shows higher liver distribution for both of QT(1015.80 h·mg/mL)and integral nanocrystals(259.63 e10 h·[p/s]/[μW/cm2])than those of QT-HNCs-280(673.82&77.66 e10 h·[p/s]/[μW/cm2])following intravenous administration.The absolute exposure of integral QT-HNCs in liver following oral administration of QT-HNCs are 8.78%for QT-HNCs-280 and 5.88%for QT-HNCs-550,while the absolute exposure of total QT for QT-HNCs-280 and QT-HNCs-550 are 21.80%and 11.61%,respectively.Owing to imprecise quantifcation method,a surprisingly high contribution of integral QT-HNCs to oral bioavailability enhancement of QT(40.27%for QT-HNCs-280 and 50.65%for QT-HNCs-550)was obtained.These results revealed signifcant difference in absorption and biodistrbution between integral nanocrystals and overall drugs following oral and intravenous administration of QT-HNCs,and provided a meaningful reference for the contribution of integral nanocrystals to overall bioavailability enhancement.

Improved stability and oral bioavailability of Ganneng dropping pills following transforming lignans of herpeto- spermum caudigerum into nanosuspensions

The present study was designed to improve storage stability and oral bioavailability of Ganneng dropping pills(GNDP) by transforming lignans of Herpetospermum caudigerum(HL) composed of herpetrione(HPE) and herpetin(HPN) into nanosuspension(HL-NS), the main active ingredient of GNDP, HL-NS was prepared by high pressure homogenization and lyophilized to transform into solid nanoparticles(HL nanoparticles), and then the formulated HL nanoparticles were perfused into matrix to obtain NS-GNDP by melting method. For a period of 3 months, the content uniformity, storage stability and pharmacokinetics test in vivo of NS-GNDP were evaluated and compared with regular GNDP at room temperature. The results demonstrated that uniformity of dosage units of NS-GNDP was acceptable according to the criteria of Chinese Pharmacopoeia 2015 J. Physical stability of NS-GNDP was investigated systemically using photon correlation spectroscopy(PCS), zeta potential measurement, and scanning electron microscopy(SEM). There was a slight increase in particles and PI of HL-NS re-dispersed from NS-GNDP after storage for 3 months, compared with new formulated NS-GNDP, which indicated a good redispersibility of the NS-GNDP containing HL-NS after storage. Besides, chemical stability of NS-GNDP was studied and the results revealed that HPE and HPN degradation was less when compared with that of GNDP, providing more than 99% of drug residue after storage for 3 months. In the dissolution test in vitro, NS-GNDP remarkably exhibited an increased dissolution velocity compared with GNDP and no distinct dissolution difference existed within 3 months. The pharmacokinetic study showed that HPE and HPN in NS-GNDP exhibited a significant increase in AUC0–t, Cmax and decrease in Tmax when compared with regular GNDP. These results indicated that NS-GNDP possessed superiority with improved storage stability and increased dissolution rate and oral bioavailability.

Formulation of dried lignans nanosuspension with high redispersibility to enhance stability,dissolution,and oral bioavailability

Herpetospermum caudigerum lignans(HTL), one of the potential drugs with anti-hepatitis B virus and hepatoprotective effects, has limited clinical applications because of poor aqueous solubility and low bioavailability. Both herpetrione(HPE) and herpetin(HPN) are the most abundant ingredients in HTL and exhibit weak acidity. The purpose of the present study was to produce dried preparations of HTL(composed of HPE and HPN) nanosuspensions(HTL-NS) with high redispersibility using lyophilization technology. The HTL-NS was prepared by utilizing precipitation-combined homogenization technology based on acid-base neutralization reactions, and critical formulation and process parameters affecting the characteristics of HTL-NS were optimized. The resultant products were characterized by particle size analysis, SEM, XRD, stability, solubility, dissolution and in vivo bioavailability. HTL-NS showed near-spherical-shaped morphology and the size was 243 nm with a narrow PDI value of 0.187. The dried preparations with a relatively large particle size of 286 nm and a PDI of 0.215 were achieved by using 4%(W/V) mannitol as cryoprotectants, and had a better stability at 4 or 25 oC for 2 months, compared to HTL-NS. In the in vitro test, the dried preparations showed markedly increased solubility and dissolution velocity. Besides, in the in vivo evaluation, it exhibited significant increases in AUC0–t, C_(max), MRT and a decrease in T_(max), compared to the raw drug.. In conclusion, our results provide a basis for the development of a drug delivery system for poorly water-soluble ingredients with p H-dependent solubility.

Semi-elastic core-shell nanoparticles enhanced the oral bioavailability of peptide drugs

The rigidity of nanoparticles was newly reported to influence their oral delivery.Semi-elastic nanoparticles can enhance the penetration in mucus and uptake by epithelial cells.However,it is still challenging and unclear that the semi-elastic core-shell nanoparticles can enhance the oral bioavailability of peptide drugs.This study was for the first time to validate the semi-elastic coreshell poly(lactic-co-glycolic acid)(PLGA)-lipid nanoparticles(LNPs)as the carrier of the oral peptide drug.The antihypertensive peptide Val-Leu-Pro-Val-Pro(VP5)loaded LNPs(VP5-LNPs)were prepared by a modified thin-film ultrasonic dispersion method.Uptake experiment was performed in Caco-2 and HT-29 cells and monito red by high content screening(HCS)and flow cyto metric(FCM).Pharmacokinetics of VP5-LNPs was carried out in Sprague-Dawley(SD)rats and analyzed by DAS 2.0.The optimal VP5-LNPs had an average particle size of 247.3±3.8 nm,zeta potential of-6.57±0.45 mV and excellent entrapment efficiency(EE)of 89.88%±1.23%.Transmission electron microscope(TEM)and Differential scanning calorimeter(DSC)further confirmed the core-shell structure.VP5-LNPs could increase the cellular uptake in vitro and have a 2.55-fold increase in AUC0-72 h,indicating a great promotion of the o ral bioavailability.The semi-elastic LNPs remarkably improved the oral availability of peptide and could be a promising oral peptide delivery system for peptide drugs in the future.

Current prodrug strategies for improving oral absorption of nucleoside analogues

Nucleoside analogues are first line chemotherapy in various severe diseases:AIDS(acquired immunodeficiency disease syndrome),cytomegalovirus infections,cancer,etc.However,many nucleoside analogues exhibit poor oral bioavailability because of their high polarity and low intestinal permeability.In order to get around this drawback,prodrugs have been utilized to improve lipophilicity by chemical modification of the parent drug.Alternatively,prodrugs targeting transporters present in the intestine have been applied to promote the transport of the nucleoside analogues.Valacyclovir and valganciclovir are two classic valine ester prodrugs transported by oligopeptide transporter 1.The ideal prodrug achieves delivery of a parent drug by attaching a non-toxic moiety that is stable during transport,but is readily degraded to the parent drug once at the target.This article presents advances of prodrug approaches for enhancing oral absorption of nucleoside analogues.

Exploring the potential of functional polymer-lipid hybrid nanoparticles for enhanced oral delivery of paclitaxel

Most biopharmaceutics classification system(BCS)class IV drugs,with poor solubility and inferior permeability,are also substrates of P-glycoprotein(P-gp)and cytochrome P450(CYP450),leading to their low oral bioavailability.The objective of this study is to explore the potential of using functional polymer-lipid hybrid nanoparticles(PLHNs)to enhance the oral absorption of BCS IV drugs.In this paper,taking paclitaxel(PTX)as a drug model,PTX-loaded PLHNs were prepared by a self-assembly method.Chitosan was selected to modify the PLHN to enhance its mucoadhesion and stability.Three P-gp inhibitors(D-α-tocopherol polyethylene glycol 1000 succinate,pluronic P123 and Solutol RHS15)were incorporated into selected PLHNs,and a CYP450 inhibitor(the extract of VBRB,BC0)was utilized to jointly promote the drug absorption.Properties of all the PLHNs were characterized systemically,including particle size,zeta potential,encapsulation efficiency,morphology,stability,in vitro drug release,mucoadhesion,in situ intestinal permeability and in vivo systemic exposure.It was found mucoadhesion of the CS-modified PLHNs was the strongest among all the formulations tested,with absolute bioavailability 21.95%.P-gp and CYP450 inhibitors incorporation further improved the oral bioavailability of PTX to 42.60%,8-fold increase compared with that of PTX itself(4.75%).Taken together,our study might shed light on constructing multifunctional PLHNs based on drug delivery barriers for better oral absorption,especially for BCS IV drugs.

Preparation and Evaluation of Insulin-loaded Nanoparticles based on Hydroxypropyl-β-cyclodextrin Modified Carboxymethyl Chitosan for Oral Delivery

Novel insulin-loaded nanoparticles based on hydroxypropyl-β-cyclodextrin modified carboxymethyl chitosan（CMC-HP-β-CD） were prepared to improve the oral bioavailability of insulin. The CMC-HP-β-CD was characterized by FT-IR spectroscopy and 1H-NMR spectra. The insulin-loaded nanoparticles were prepared through crosslinking with calcium ions, and the morphology and size of the prepared nanoparticles were characterized by transmission electron microscopy（TEM） and dynamic light scattering（DLS）. Cumulative release in vitro study was performed respectively in simulated gastric medium fluid（SGF, p H=1.2）, simulated intestinal fluid（SIF, p H=6.8） and simulated colonic fluid（SCF, p H=7.4）. The encapsulation efficiency of insulin was up to 87.14 ± 4.32% through high-performance liquid chromatography（HPLC）. Statistics indicated that only 15% of the encapsulated insulin was released from the CMC-HP-β-CD nanoparticles in 36 h in SGF, and about 50% of the insulin could be released from the nanoparticles in SIF, whereas more than 80% was released in SCF. In addition, the solution containing insulin nanoparticles could effectively reduce the blood glucose level of diabetic mice. The cytotoxicity test showed that the samples had no cytotoxicity. CMC-HP-β-CD nanoparticles are promising candidates as potential carriers in oral insulin delivery systems.

Pharmacokinetics/Pharmacodynamics study of Fixtral SB as compared to supra bioavailable itraconazole and conventional itraconazole

BACKGROUND Itraconazole is a broad-spectrum triazole antifungal inhibiting fungal growth by inhibiting ergosterol synthesis and exhibits a nonlinear pharmacokinetic profile.Erratic absorption pattern with wide fluctuations in blood levels causes inconsistent and unpredictable clinical behaviour of this drug despite its low minimum inhibitory concentration(MIC)as compared to other antifungal agents.AIM To compare the oral bioavailability and bioequivalence of Fixtral SB(supra bioavailable itraconazole)with reference product R2(supra bioavailable 2×50 mg itraconazole).METHODS The study population consisted of 54 healthy volunteers,aged between 18-45 years and randomized to receive a single oral dose of either test[T;Fixtral SB(supra bioavailable itraconazole)100 mg]or reference product(R1;Sporanox 100 mg×2 capsules and R2;Lozanoc capsules 50 mg×2 capsules).Blood samples were taken pre-dose and post-dose up to 96 h.The study evaluated bioequivalence by comparing the oral bioavailability of the test product with reference product R2.The pharmacodynamic characteristics of the drug were evaluated by comparing the test product with reference product R1.Pharmacokinetics(PK)-PD comparative analysis[area under the concentration-time curve(AUC)/minimum inhibitory concentration(MIC)>25]was performed for conventional itraconazole 100 mg and supra bioavailable itraconazole 50 mg.Adverse events(AEs)assessments were performed in each study period and post-study evaluation.RESULTS Statistical analysis of primary PK variables revealed bioequivalence,with confidence intervals being completely inside the acceptance criteria of 80%-125%.The peak concentration levels of itraconazole were achieved at 10 h(T)and 8.5 h(R2),respectively.Pharmacodynamic parameter assessment showed that AUC/MIC for R1 are comparable to Fixtral SB 100mg for MIC levels up to 16mcg/mL(P>0.05 and observed P=0.3196).Six AEs were observed that were mild to moderate in severity and resolved.No severe AE was reported.CONCLUSION Test product itraconazole Capsule 100 mg is bioequivalent with the reference product(R2)at 100 mg dose(2 capsules of Lozanoc®50 mg)under fed conditions.Pharmacodynamics activity in terms of AUC/MIC is comparable between the test product at 100 mg dose and marketed itraconazole 200 mg.Fixtral SB is expected to have therapeutically similar efficacy at half the equivalent dose.Tested formulations were found to be safe and well tolerated.

Interactions between gut microbiota and berberine,a necessary procedure to understand the mechanisms of berberine

Berberine(BBR),an isoquinoline alkaloid,has been found in many plants,such as Coptis chinensis Franch and Phellodendron chinense Schneid.Although BBR has a wide spectrum of pharmacological effects,its oral bioavailability is extremely low.In recent years,gut microbiota has emerged as a cynosure to understand the mechanisms of action of herbal compounds.Numerous studies have demonstrated that due to its low bioavailability,BBR can interact with the gut microbiota,thereby exhibiting altered pharmacological effects.However,no systematic and comprehensive review has summarized these interactions and their corresponding influences on pharmacological effects.Here,we describe the direct interactive relationships between BBR and gut microbiota,including regulation of gut microbiota composition and metabolism by BBR and metabolization of BBR by gut microbiota.In addition,the complex interactions between gut microbiota and BBR as well as the side effects and personalized use of BBR are discussed.Furthermore,we provide our viewpoint on future research directions regarding BBR and gut microbiota.This review not only helps to explain the mechanisms underlying BBR activity but also provides support for the rational use of BBR in clinical practice.

Advances in oral peptide drug nanoparticles for diabetes mellitus treatment

Peptide drugs play an important role in diabetes mellitus treatment.Oral administration of peptide drugs is a promising strategy for diabetes mellitus because of its convenience and high patient compliance compared to parenteral administration routes.However,there are a series of formidable unfavorable conditions present in the gastrointestinal(GI)tract after oral administration,which result in the low oral bioavailability of these peptide drugs.To overcome these challenges,various nanoparticles(NPs)have been developed to improve the oral absorption of peptide drugs due to their unique in vivo properties and high design flexibility.This review discusses the unfavorable conditions present in the GI tract and provides the corresponding strategies to overcome these challenges.The review provides a comprehensive overview on the NPs that have been constructed for oral peptide drug delivery in diabetes mellitus treatment.Finally,we will discuss the rational application and give some suggestions that can be utilized for the development of oral peptide drug NPs.Our aim is to provide a systemic and comprehensive review of oral peptide drug NPs that can overcome the challenges in GI tract for efficient treatment of diabetes mellitus.

Probing the new strategy for the oral formulations of taxanes:changing the method with the situation

The first-generation taxanes(including paclitaxel and docetaxel)are widely used for the treatment of various cancers in clinical settings.In the past decade,a series of new-generation taxanes have been developed which are effective in the inhibition of tumor resistance.However,intravenous(i.v.)infusion is still the only route of administration,and may result in serious adverse reactions with respect to the utilization of Cremophor EL or Tween-80 as solvent.Besides,the dosing schedule is also limited.Therefore,oral administration of taxanes is urgently needed to avoid the adverse reactionss and increase dosing frequency.In this review,we first outlined the discovery and development of taxane-based anticancer agents.Furthermore,we summarized the research progress on the oral formulations of taxanes and proposed some thoughts on the future development of oral taxane formulations.

Can remdesivir and its parent nucleoside GS-441524 be potential oral drugs? An in vitro and in vivo DMPK assessment

Remdesivir(RDV) is the only US Food and Drug Administration(FDA)-approved drug for treating COVID-19.However,RDV can only be given by intravenous route,and there is a pressing medical need for oral antivirals.Significant evidence suggests that the role of the parent nucleoside GS-441524 in the clinical outcomes of RDV could be largely underestimated.We performed an in vitro and in vivo drug metabolism and pharmacokinetics(DMPK) assessment to examine the potential of RDV,and particularly GS-441524,as oral drugs.In our in vitro assessments,RDV exhibited prohibitively low stability in human liver microsomes(HLMs,t1/2=-1 min),with the primary CYP-mediated metabolism being the mono-oxidation likely on the phosphoramidate moiety.This observation is poorly aligned with any potential oral use of RDV,though in the presence of cobicistat,the microsomal stability was drastically boosted to the level observed without enzyme cofactor NADPH.Conversely,GS-441524 showed excellent metabolic stability in human plasma and HLMs.In further in vivo studies in CD-1 mice,GS-441524 displayed a favorable oral bioavailability of 57%.Importantly,GS-441524 produced adequate drug exposure in the mice plasma and lung,and was effectively converted to the active triphosphate,suggesting that it could be a promising oral antiviral drug for treating COVID-19.

Discovery of an orally active VHL-recruiting PROTAC that achieves robust HMGCR degradation and potent hypolipidemic activity in vivo

HMG-CoA reductase(HMGCR) protein is usually upregulated after statin(HMGCR inhibitor) treatment, which inevitably diminishes its therapeutic efficacy, provoking the need for higher doses associated with adverse effects. The proteolysis targeting chimera(PROTAC) technology has recently emerged as a powerful approach for inducing protein degradation. Nonetheless, due to their bifunctional nature, developing orally bioavailable PROTACs remains a great challenge. Herein, we identified a powerful HMGCR-targeted PROTAC(21 c) comprising a VHL ligand conjugated to lovastatin acid that potently degrades HMGCR in Insig-silenced HepG2 cells(DC50 Z 120 nmol/L) and forms a stable ternary complex, as predicated by a holistic modeling protocol. Most importantly, oral administration of the corresponding lactone 21 b reveled favorable plasma exposures referring to both the parent 21 b and the conversed acid 21 c. Further in vivo studies of 21 b demonstrated robust HMGCR degradation and potent cholesterol reduction in mice with diet-induced hypercholesterolemia, highlighting a promising strategy for treating hyperlipidemia and associated diseases.

Current strategies for improving limitations of proteolysis targeting chimeras

Proteolysis targeting chimeras(PROTACs)are bifunctional degrader molecules via hijacking the ubiquitinproteasome system(UPS)to specifically eliminate targeted proteins.PROTACs have gained momentum as a new modality of attractive technologies in the drug discovery landscape,since it allows to degrade disease-related proteins effectively.Although some PROTACs drugs reached the clinical research,they are still facing some bottlenecks and challenges that should not be neglected,such as poor oral bioavailability and potential toxic side effects.To overcome these limitations,herein,we provide an overview of recent strategies for improving the durability of PROTACs by enhancing cell permeability and reducing toxic side effects.Meanwhile,the impact of these strategies on improving oral bioavailability as well as their advantages and drawbacks will also be discussed.This review will give a useful reference toolbox for PROTACs design and further promote its clinical application.

Alcohol consumption promotes arsenic absorption but reduces tissue arsenic accumulation in mice

Alcohol consumption alters gut microflora and damages intestinal tight junction barriers,which may affect arsenic(As)oral bioavailability.In this study,mice were exposed to arsenate in the diet(6μg/g)over a 3-week period and gavaged daily with Chinese liquor(0.05 or 0.10 mL per mouse per day).Following ingestion,78.0%and 72.9%of the total As intake was absorbed and excreted via urine when co-exposed with liquor at daily doses of 0.05 or 0.10 mL,significantly greater than when As was supplied alone(44.7%).Alcohol co-exposure significantly altered gut microbiota but did not significantly alter As biotransformation in the intestinal tract or tissue.Significantly lower relative mRNA expression was observed for genes encoding for tight junctions in the ileum of liquor co-exposed mice,contributing to greater As bioavailability attributable to enhanced As absorption via the intestinal paracellular pathway.However,As concentration in the liver,kidney,and intestinal tissue of liquortreated mice was decreased by 24.4%-42.6%,27.5%-38.1%,and 28.1%-48.9%compared to control mice.This was likely due to greater renal glomerular filtration rate induced by alcohol,as suggested by significantly lower expression of genes encoding for renal tight junctions.In addition,in mice gavaged daily with 0.05 mL liquor,the serum antidiuretic hormone level was significantly lower than control mice(2.83±0.59 vs.5.40±1.10 pg/mL),suggesting the diuretic function of alcohol consumption,which may facilitate As elimination via urine.These results highlight that alcohol consumption has a significant impact on the bioavailability and accumulation of As.

A lipophilic prodrug of Danshensu:preparation,characterization,and in vitro and in vivo evaluation

Danshensu [3-(3, 4-dihydroxyphenyl) lactic acid, DSS], one of the significant cardioprotective components, is extracted from the root of Salvia miltiorrhiza. In the present study, an ester prodrug of Danshensu(DSS), palmitoyl Danshensu(PDSS), was synthesized with the aim to improve its oral bioavailability and prolong its half-life. The in vitro experiments were carried out to evaluate the physicochemical properties and stability of PDSS. Although the solubility of PDSS in water was only 0.055 mg·mL^(-1), its solubility in Fa SSIF and Fe SSIF reached 4.68 and 9.08 mg·mL^(-1), respectively. Octanol-water partition coefficient(log P) was increased from-2.48 of DSS to 1.90 of PDSS. PDSS was relatively stable in the aqueous solution in pH range from 5.6 to 7.4. Furthermore, the pharmacokinetics in rats was evaluated after oral administration of PDSS and DSS. AUC and t1/2 of PDSS were enhanced up to 9.8-fold and 2.2-fold, respectively, compared to that of DSS. Cmax was 1.67 ± 0.11 μg·mL^(-1) for PDSS and 0.81 ± 0.06 μg·m L-1 for DSS. Thus, these results demonstrated that PDSS had much higher oral bioavailability and longer circulation time than its parent drug.