Biomimetic Antidote Nanoparticles: a Novel Strategy for Chronic Heavy Metal Poisoning.

Chronic lead poisoning has become a major factor in global public health. Chelation therapy is usually used to manage lead poisoning. Dimercaptosuccinic acid (DMSA) is a widely used heavy metal chelation agent. However, DMSA has the characteristics of poor water solubility, low oral bioavailability, and short half-life, which limit its clinical application. Herein, a long-cycle slow-release nanodrug delivery system was constructed. We successfully coated the red blood cell membrane (RBCM) onto the surface of dimercaptosuccinic acid polylactic acid glycolic acid copolymer (PLGA) nanoparticles (RBCM-DMSA-NPs), which have a long cycle and detoxification capabilities. The NPs were characterized and observed by particle size meters and transmission electron microscopy. The results showed that the particle size of RBCM-DMSA-NPs was approximately 146.66 ± 2.41 nm, and the zeta potential was - 15.34 ± 1.60 mV. The homogeneous spherical shape and clear core-shell structure of the bionic nanoparticles were observed by transmission electron microscopy. In the animal tests, the area under the administration time curve of RBCM-DMSA-NPs was 156.52 ± 2.63 (mg/L·h), which was 5.21-fold and 2.36-fold that of free DMSA and DMSA-NPs, respectively. Furthermore, the median survival of the RBCM-DMSA-NP treatment group (47 days) was 3.61-fold, 1.32-fold, and 1.16-fold for the lead poisoning group, free DMSA, and DMSA-NP groups, respectively. The RBCM-DMSA-NP treatment significantly extended the cycle time of the drug in the body and improved the survival rate of mice with chronic lead poisoning. Histological analyses showed that RBCM-DMSA-NPs did not cause significant systemic toxicity. These results indicated that RBCM-DMSA-NPs could be a potential candidate for long-term chronic lead exposure treatment.

[Optimization of formulation of paclitaxel nanosuspension encapsulated by erythrocyte membrane based on Box-Behnken method].

In view of the longevity and innate immune escape of red blood cells, this study designed the red blood cell membrane-coated paclitaxel nanosuspension [RBC-(PTX)NS] and investigated its physicochemical properties and antitumor effect in vitro. Paclitaxel nanosuspension [(PTX)NS] was prepared by ultrasonic precipitation and then RBC-(PTX)NS by ultrasonic coating. The formulation of(PTX)NS was optimized with Box-Behnken method and indexes of particle diameter, zeta potential, and stability. The morphology, particle diameter, stability, in vitro dissolution, and antitumor effect of(PTX)NS and RBC-(PTX)NS were characterized. The results showed that the particle diameter and zeta potential were(129.38±0.92) nm and(-22.41±0.48) mV, respectively, for the optimized(PTX)NS, while(142.5±0.68) nm and(-29.85±0.53) mV, respectively, for RBC-(PTX)NS. Under the transmission electron microscope,(PTX)NS was spherical and RBC-(PTX)NS had obvious core-shell structure. RBC-(PTX)NS remained stable for 5 days at 4 ℃. The in vitro dissolution test demonstrated that the cumulative release rate of RBC-(PTX)NS reached 79% within 20 min, which was significantly higher than that(25%) of(PTX)NS(P<0.05). As evidenced by MTT assay, RBC-(PTX)NS highly inhibited the proliferation of HepG2 cells in a dose-dependent manner. The cell membrane-coated nano-preparation preparation method is simple and reproducible. It improves the solubility of PTX and endows RBC-(PTX)NS with higher stability and stronger cytotoxicity. Thus, it is a new method for the delivery of PTX via nanocrystallization.

Hybrid membrane-coated nanosuspensions for multi-modal anti-glioma therapy via drug and antigen delivery.

BACKGROUND: Glioma is one of the deadliest human cancers. Although many therapeutic strategies for glioma have been explored, these strategies are seldom used in the clinic. The challenges facing the treatment of glioma not only involve the development of chemotherapeutic drugs and immunotherapeutic agents, but also the lack of a powerful platform that could deliver these two moieties to the targeted sites. Herein, we developed chemoimmunotherapy delivery vehicles based on C6 cell membranes and DC membranes to create hybrid membrane-coated DTX nanosuspensions (DNS-[C6&DC]m). RESULTS: Results demonstrated successful hybrid membrane fusion and nanosuspension functionalization, and DNS-[C6&DC]m could be used for different modes of anti-glioma therapy. For drug delivery, membrane coating could be applied to target the source cancer cells via a homotypic-targeting mechanism of the C6 cell membrane. For cancer immunotherapy, biomimetic nanosuspension enabled an immune response based on the professional antigen-presenting characteristic of the dendritic cell membrane (DCm), which carry the full array of cancer cell membrane antigens and facilitate the uptake of membrane-bound tumor antigens for efficient presentation and downstream immune n. CONCLUSION: DNS-[C6&DC]m is a multifunctional biomimetic nano-drug delivery system with the potential to treat gliomas through tumor-targeted drug delivery combined with immunotherapy, thereby presenting a promising approach that may be utilized for multiple modes of cancer therapy.

First report of Fusarium fujikuroi causing bulb rot on Lilium lancifolium in China.

Lilium lancifolium Thunb., commonly known as Juandan lily and tiger lily, is widely cultivated in China for its edible bulbs and medicinal properties, with a commercial value worth of ~RMB 6 billion Yuan per year. Bulb rot is an increasingly common disease on L. lancifolium, significantly impacting both the quantity and quality of the main product, the scaled bulbs. Typically, the causal pathogens invade the plant through wounds in the root or the ends of the bulb, causing the roots and bulb to brown and rot, which can eventually lead to stem wilt and death of the whole plants. During pathogenesis, the infected bulbs typically turn from white to brown, with sunken lesions and later the scales flaking off from the base of the bulb (Figure 1A and 1B). Plants growing from infected bulbs are generally short, with discolored leaves, wilting, and death at an early stage. Bulb rot is commonly observed in fields with excess water and a history of continuous Juandan lily cultivation. For this study, wilted L. lancifolium plants with rotted bulbs were collected from Longshan in Hunan, Enshi in Hubei, Yixing in Jiangsu, and Lu'an in Anhui in 2018 and 2019. Infected bulbs were surface sterilized with 75% ethanol for 30 seconds, followed by disinfection with 2% sodium hypochlorite for 5 minutes, and then rinsing with sterile water three times. The surface-sterilized tissue was divided into small pieces of 0.5 × 0.5 cm in size, placed on potato dextrose agar (PDA) medium containing 50 mg/l streptomycin sulfate, and incubated at 25℃. Mycelia growing from diseased tissues were sub-cultured onto fresh PDA medium to obtain pure culture, which formed dense white hyphae after a few days (Figure 1C and 1D). Colonies on PDA produced abundant condia about 15 days after subculturing. Microconidia were abundant, solitary, thin walled, hyaline, ovoid, 0 to 1 septate, with an average size of 6.1 × 2.6 µm (n=50) (Figure 1E). Macroconidia had a curved apical cell and foot-like basal cell with 3 to 5 septa, with an average size of 35.4 × 4.3 µm (n=30) (Figure 1E). No chlamydospore was observed. These morphological characteristics of the causal pathogen were similar to those of Fusarium spp. (Leslie et al., 2006). To identify the Fusarium isolates to species level, DNA fragments of the internal transcribed spacer (ITS) regions of the ribosomal RNA gene cluster, translation elongation factor subunit 1-alpha (TEF1-α), and RNA polymerase II subunit 2 (RPB2) genes were amplified using primers ITS1/ITS4, EF1/EF2, and 7cF/11aR respectively and sequenced (Choi et al. 2018; Jiang et al. 2018; Choi et al. 2017). BLAST analyses showed that the ITS (GenBank Accession No. MT549849), TEF1-α (GenBank Accession No. MT553348), and RPB2 (Accession No. MW201686) sequences of our isolates shared the highest sequence identities (98-100%) with those of F. fujikuroi reference strains in GenBank. A phylogenetic tree showing the relationship between one of our strains, S106, and those of the closely related species within the F. fujikuroi species complex was constructed by the maximum likelihood method using MEGA X (Kumar et al. 2018) (Figure 2). Based on the morphological characteristics and DNA sequences, the strains were identified as F. fujikuroi sensu stricto. We used two methods, an ex vivo assay using Juandan lily bulb scales and an in vivo assay using potted Juandan lily plants, to confirm pathogenicity for one representative F. fujikuroi strain from each of the four geographic regions to fulfill Koch's postulates (Bian et al. 2016; Zeng et al. 2019). In the ex vivo assay, actively growing mycelia on PDA plates were cut into 5mm diameter fungal blocks as inocula. To prepare healthy Juandan lily bulb scales as test tissues, healthy fresh scales were first surface sterilized using 75% alcohol for 30 seconds, followed by treatment of 2% sodium hypochlorite for 5 minutes, and then rinsed with sterile water 3 times. The scales were punctured with sterilized dissecting needles, the 5mm mycelial blocks containing the PDA medium were then inoculated on the punctured wound of the scales. Sterile PDA culture medium without mycelia was inoculated on the punctured wound as a negative control. After inoculation, Juandan lily scales were placed in sterile culture dishes with two layers of sterilized filter paper and 5ml of sterile water in each dish. Six Juandan lily scales were placed in each dish, with different treatments placed in different dishes, and the dishes were placed in an incubator in the dark at 25℃. After 10 days of incubation, we found that the F. fujikuroi-inoculated Juandan lily bulb scales showed disease symptoms (brownish lesion) similar to those in the original field collected infected bulb samples (Figure 1F). However, such symptoms were not observed in the negative control group. The pathogenicity test was performed 3 times for each isolate, each with six repeats. In the in vivo pathogenicity test using potted lily plants, we prepared actively growing cultures of our F. fujikuroi strains by incubating them in a liquid medium, the potato dextrose broth, for 3 days in a shaker-incubator at 25℃ and 180rpm. The asexual spores conidia from the fungal cultures were harvested by filtration through eight layers of sterile cheese clothes and with spore concentrations adjusted to 1×107 conidia per ml. Healthy Juandan lily bulbs were selected and one bulb was planted in each pot containing sterilized soil. Each pot was inoculated with 1ml conidia suspension, at the base soil where the bulbs were planted. The pots were placed in a growth chamber at 25℃ with a 12 h light and 12 h dark cycle. Symptoms similar to those observed in diseased bulbs in the field were observed, with symptoms at 30 days after inoculations shown in Figure 3. Specifically, most of the roots, bulb plate and scale tissues of Juandan lily plants inoculated with F. fujikuroi conidia were rotten and turned black, with few new roots. In addition, the infected plants showed stunted growth (Figure 3). In contrast, the uninoculated plants grew normally, with dense new roots and healthy-looking bulbs, and no rot symptom (Figure 3). The fungi were re-isolated from the infected Juandan lily tissues from both pathogenicity assays, following the procedures described above for isolating and identifying the fungal cultures from infected field samples. These re-isolated fungi were shown to have colony morphology and DNA sequences at the three loci identical to those of our inoculated F. fujikuroi strains. Several Fusarium species have been reported as pathogens of lily plants in China, including F. oxysporum, F. solani and F. tricinctum (Li, et al., 1995; Li, et al., 2013). In addition, F. redolens has been reported previously in ornamental lily in Ukraine (Zerova, 1940). Indeed, Fusarium moniliforme, one of the disused synonyms of F. fujikuroi (Seifert et al. 2003), has been reported as a causal agent for diseases in lily. However, it's now known that the originally defined F. fujikuroi sensu lato is in fact a large species complex consisting of over 60 recognized species, including F. fujikuroi sensu stricto (Moussa et al. 2017; Choi et al. 2018). In addition, there are over 100 species in the genus Lilium as well as many other species with their common names including the word "lily" but are not in the Lilium genus. To our knowledge, this is the first confirmed report of bulb rot of Juandan lily L. lancifolium caused by F. fujikuroi sensu stricto in China. Our result should help with future monitoring and control of Juandan lily diseases.

Genome-Wide Analysis of Alternative Splicing and Non-Coding RNAs Reveal Complicated Transcriptional Regulation in Cannabis sativa L.

It is of significance to mine the structural genes related to the biosynthetic pathway of fatty acid (FA) and cellulose as well as explore the regulatory mechanism of alternative splicing (AS), microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) in the biosynthesis of cannabinoids, FA and cellulose, which would enhance the knowledge of gene expression and regulation at post-transcriptional level in Cannabis sativa L. In this study, transcriptome, small RNA and degradome libraries of hemp 'Yunma No.1' were established, and comprehensive analysis was performed. As a result, a total of 154, 32 and 331 transcripts encoding key enzymes involved in the biosynthesis of cannabinoids, FA and cellulose were predicted, respectively, among which AS occurred in 368 transcripts. Moreover, 183 conserved miRNAs, 380 C. sativa-specific miRNAs and 7783 lncRNAs were predicted. Among them, 70 miRNAs and 17 lncRNAs potentially targeted 13 and 17 transcripts, respectively, encoding key enzymes or transporters involved in the biosynthesis of cannabinoids, cellulose or FA. Finally, the crosstalk between AS and miRNAs or lncRNAs involved in cannabinoids and cellulose was also predicted. In summary, all these results provided insights into the complicated network of gene expression and regulation in C. sativa.

Cancer Cell Membrane-Coated Nanosuspensions for Enhanced Chemotherapeutic Treatment of Glioma.

Effective intracerebral delivery is key for glioma treatment. However, the drug delivery system within the brain is largely limited by its own adverse physical and chemical properties, low targeting efficiency, the blood-brain barrier and the blood-brain tumor barrier. Herein, we developed a simple, safe and efficient biomimetic nanosuspension. The C6 cell membrane (CCM) was utilized to camouflaged the 10-hydroxycamptothecin nanosuspension (HCPT-NS) in order to obtain HCPT-NS/CCM. Through the use of immune escape and homotypic binding of the cancer cell membrane, HCPT-NS/CCM was able to penetrate the blood-brain barrier and target tumors. The HCPT-NS is only comprised of drugs, as well as a small amount of stabilizers that are characterized by a simple preparation method and high drug loading. Similarly, the HCPT-NS/CCM is able to achieve targeted treatment of glioma without any ligand modification, which leads it to be stable and efficient. Cellular uptake and in vivo imaging experiments demonstrated that HCPT-NS/CCM is able to effectively cross the blood-brain barrier and was concentrated at the glioma site due to the natural homing pathway. Our results reveal that the glioma cancer cell membrane is able to promote drug transport into the brain and enter the tumor via a homologous targeting mechanism.

Co-delivery of CPP decorated doxorubicin and CPP decorated siRNA by NGR-modified nanobubbles for improving anticancer therapy.

A combination of doxorubicin (DOX) and small interfering RNA (siRNA) is proven effective for the reverse of multidrug resistance. However, rapid degradation and poor cellular internalization of siRNA hinder their synergistic action. To improve the combination effect, asparagine-glycine-arginine peptide (NGR) -modified nanobubbles (NBs) containing cell-penetrating peptide (CPP) decorated DOX and CPP decorated c-myc siRNA were constructed. Diameters of these NBs were about 245 nm and zeta potentials were about -3 mV. Encapsulation efficiencies (EE) of DOX exceeded 80%. Release of DOX could be triggered by ultrasound (US) since above 80% DOX was released from NBs after sonication while less than 5% DOX was discharged without treatment of US. These NBs were considered stable during 24 h since the decrease of particle size was no more than 10 nm, variances of EE were less than 5%, and changes of transmission (ΔT) were less than 3%. More drugs in formulation decorated with CPP and NGR were accumulated in the tumor when combined with sonication. The evident synergistic action of DOX, siRNA, NBs, and US was verified in mice with strong antitumor efficacy. Taken together, NGR-modified NBs containing CPP-DOX and CPP-siRNA are able to realize time- and spatial-controlled drug delivery and show potential application prospects.

Genome Sequence Resource for the Ramie Oomycete Pathogen Phytopythium vexans HF1.

The oomycete Phytopythium vexans is a causative agent of patch canker, damping-off, and crown, stem, and root rot in many economically important plants. P. vexans HF1 was isolated in China, where it caused brown root rot of ramie, a fiber crop broadly cultivated in Asia. The genome of HF1 was sequenced by a combination of technologies producing short (Illumina HiSeq X) and long (PacBio RS) reads. The genome is 41.73 Mbp long, assembled into 44 contigs. It has a GC content of 58.17% and contains 13,051 predicted coding genes, including 1,461 putative virulence genes and 220 putative antimicrobial resistance genes. This genome sequence provides a resource for determining the molecular mechanisms of disease development in this pathosystem.

Neuron tau-targeting biomimetic nanoparticles for curcumin delivery to delay progression of Alzheimer's disease.

BACKGROUND: Although many therapeutic strategies for Alzheimer's disease (AD) have been explored, these strategies are seldom used in the clinic. Therefore, AD therapeutic research is still urgently needed. One major challenge in the field of nanotherapeutics is to increase the selective delivery of drugs to a targeted location. Herein, we devised and tested a strategy for delivery of nanoparticles to neurons to inhibit tau aggregation by directly targeting p-tau. RESULTS: Curcumin (CUR) is loaded onto red blood cell (RBC) membrane-coated PLGA particles bearing T807 molecules attached to the RBC membrane surface (T807/RPCNP). With the advantage of the suitable physicochemical properties of the PLGA nanoparticles and the unique biological functions of the RBC membrane, the RPCNP are stabilized and promote sustained CUR release, which provided improved biocompatibility and resulted in long-term presence in the circulation. Under the synergistic effects of T807, T807/RPCNP can not only effectively penetrate the blood-brain barrier (BBB), but they also possess high binding affinity to hyperphosphorylated tau in nerve cells where they inhibit multiple key pathways in tau-associated AD pathogenesis. When CUR was encapsulated, our data also demonstrated that CUR-loaded T807/RPCNP NPs can relieve AD symptoms by reducing p-tau levels and suppressing neuronal-like cells death both in vitro and in vivo. The memory impairment observed in an AD mouse model is significantly improved following systemic administration of CUR-loaded T807/RPCNP NPs. CONCLUSION: Intravenous neuronal tau-targeted T807-modified novel biomimetic nanosystems are a promising clinical candidate for the treatment of AD.

Novel Class of Ultrasound-Triggerable Drug Delivery Systems for the Improved Treatment of Tumors.

The controlled release of anticancer drugs at the tumor site is a central challenge in treating cancer. To achieve this goal, our strategy was based on tumor-specific targeting and ultrasound-triggered release of an anticancer agent from liposomal nanocarriers. To enhance the ultrasound-triggered drug release, we incorporated a lipophilic sonosensitizer, chlorin e6 (Ce6) ester, into the lipid bilayer of liposomes. Additionally, asparagine-glycine-arginine (NGR) that binds to CD13, which is overexpressed in tumor cells, was introduced into these liposomes. Under the navigation effects of the NGR, the novel ultrasound-triggerable NGR-modified liposomal nanocarrier (NGR/UT-L) accumulates in tumor sites. Once irradiated by ultrasound in tumor tissues, the sonodynamic effect produced by Ce6 could create more efficient disruptions of the lipid bilayer of the liposomal nanocarriers. After encapsulating doxorubicin (DOX) as the model drug, the ultrasound triggered lipid bilayer breakdown can spring the immediate release of DOX, making it possible for ultrasound-responsive chemotherapy with great selectivity. By combining tumor-specific targeting and stimuli-responsive controlled release into one system, NGR/UT-L demonstrated a perfect antitumor effect. Moreover, this report provides an example of controlled-release by means of a novel class of ultrasound triggering systems.

Construction of a Glutathione-Responsive and Silica-Based Nanocomposite for Controlled Release of Chelator Dimercaptosuccinic Acid.

Dimercaptosuccinic acid (DMSA) is an oral heavy metal chelator. Although DMSA is the most acceptable chelator in the urinary excretion of toxic elements from children and adults, its defects in plasma binding and the membrane permeability limit its interaction with intracellular elements and affect its efficacy in chelation therapy. Herein, a novel nanocomposite composed of mesoporous silica nanoparticles (MSNs), disulfide bond, and DMSA was synthesized and characterized with a scanning/transmission electron microscope, IR and Raman spectra, and TGA analysis. The in vitro interactions with glutathione (GSH) and cellular uptake assays showed that it was able to be stable in extracellular environments such as in blood, be internalized by cells, and release DMSA inside via GSH-triggered disulfide cleavage reaction. The in vitro adsorption assays showed that MSNs-SH as its intracellular metabolite had strong adsorbability for models of Hg2+ or Pb2+. The hemolysis and cell viability assays showed that it was compatible with blood and cells even at a concentration of 1000 µg·mL-1. All above could not only enable it to be a GSH-responsive drug delivery system (DDS) for DMSA delivery but also to be a solution for its defects and efficacy. Thus, introduction of intelligent DDS might open a new avenue for DMSA-based chelation therapy.

Development of metoprolol tartrate-loaded sustained-release pellets: effect of talc on the mechanism of drug release.

Talc is one of the most commonly used antiadherents in the coating film. However, the mechanism of influence of talc on drug release has yet to be fully understood. In this study, metoprolol tartrate (MT)-loaded Eudragit NE 30 D-coated sustained-release (SR) pellets were prepared using talc as an antiadherent in the layering and coating processes. Talc significantly reduced the stickiness of the layered or coated substrates, thus enhancing the process smoothness. Moreover, the incorporation of talc into the coating film significantly affected drug release. The water vapor permeability and drug permeability of free films increased as the concentration of talc increased. Importantly, talc had a dynamic effect on the drug release. The drug release rate of the pellets in the initial stage (within 2 h) increased with increasing talc concentrations, which exceeded the critical pigment volume concentration resulted in leaks formation in the coated film. However, subsequent swelling of the membrane and expansion of the copolymer network eliminated the influence of talc and the drug release was then controlled by the polymeric membrane. These results suggest that talc contributed to the reduction of the sticking of layered or coated substrates, and facilitated the manufacturing process and drug release properties.

Bioavailability Improvement Strategies for Poorly Water-Soluble Drugs Based on the Supersaturation Mechanism: An Update.

The formulation development for poorly soluble drugs still remains a challenge. Supersaturating drug delivery systems (SDDS) or drug delivery systems based on supersaturating provide a promising way to improve the oral bioavailability of poorly water-soluble drugs. In supersaturable formulations, drug concentration exceeds the equilibrium solubility when exposed to gastrointestinal fluids, and the supersaturation state is maintained long enough to be absorbed, resulting in compromised bioavailability. In this article, the mechanism of generating and maintaining supersaturation and the evaluation methods of supersaturation assays are discussed. Recent advances in different drug delivery systems based on supersaturating are the focus and are discussed in detail.This article is open to POST-PUBLICATION REVIEW. Registered readers (see "For Readers") may comment by clicking on ABSTRACT on the issue's contents page.

De novo assembly and characterization of the spleen transcriptome of common carp (Cyprinus carpio) using Illumina paired-end sequencing.

Common carp (Cyprinus carpio) is one of the most important aquacultured species of the family Cyprinidae, and breeding this species for disease resistance is becoming more and more important. However, at the genome or transcriptome levels, study of the immunogenetics of disease resistance in the common carp is lacking. In this study, 60,316,906 and 75,200,328 paired-end clean reads were obtained from two cDNA libraries of the common carp spleen by Illumina paired-end sequencing technology. Totally, 130,293 unique transcript fragments (unigenes) were assembled, with an average length of 1400.57 bp. Approximately 105,612 (81.06%) unigenes could be annotated according to their homology with matches in the Nr, Nt, Swiss-Prot, COG, GO, or KEGG databases, and they were found to represent 46,747 non-redundant genes. Comparative analysis showed that 59.82% of the unigenes have significant similarity to zebrafish Refseq proteins. Gene expression comparison revealed that 10,432 and 6889 annotated unigenes were, respectively, up- and down-regulated with at least twofold changes between two developmental stages of the common carp spleen. Gene ontology and KEGG analysis were performed to classify all unigenes into functional categories for understanding gene functions and regulation pathways. In addition, 46,847 simple sequence repeats (SSRs) were detected from 35,618 unigenes, and a large number of single nucleotide polymorphism (SNP) and insertion/deletion (INDEL) sites were identified in the spleen transcriptome of common carp. This study has characterized the spleen transcriptome of the common carp for the first time, providing a valuable resource for a better understanding of the common carp immune system and defense mechanisms. This knowledge will also facilitate future functional studies on common carp immunogenetics that may eventually be applied in breeding programs.

Preparation and evaluation of orally disintegrating tablets of taste masked phencynonate HCl using ion-exchange resin.

This study was intended to design an orally disintegrating tablet (ODT) formulation that can mask the extremely bitter and metallic taste of phencynonate HCl by novel ion-exchange resins. The drug-resin complexes (DRCs) were prepared and characterized by scanning electron microscopy, X-ray powder diffraction and differential scanning calorimetry. In vitro properties (dissolution, wetting time and disintegration time) and in vivo behavior (disintegration time and taste-masking effect) in healthy volunteers of the prepared ODTs were also investigated. The drug was changed from the crystal structure to the amorphous form in the DRC. Compared with commercial tablets, the in vitro and in vivo disintegration of optimized DRC-loaded ODTs with a drug-resin ratio of 1:1 was greatly improved and better palatability with a low bitterness index (0.33) was obtained. The current DRC-loaded ODT could promise a good way to mask the unpleasant taste of certain drugs and accordingly improve the patient compliance.

Preformulation characterization and in vivo absorption in beagle dogs of JFD, a novel anti-obesity drug for oral delivery.

JFD (N-isoleucyl-4-methyl-1,1-cyclopropyl-1-(4-chlorine)phenyl-2-amylamine·HCl) is a novel investigational anti-obesity drug without obvious cardiotoxicity. The objective of this study was to characterize the key physicochemical properties of JFD, including solution-state characterization (ionization constant, partition coefficient, aqueous and pH-solubility profile), solid-state characterization (particle size, thermal analysis, crystallinity and hygroscopicity) and drug-excipient chemical compatibility. A supporting in vivo absorption study was also carried out in beagle dogs. JFD bulk powders are prismatic crystals with a low degree of crystallinity, particle sizes of which are within 2-10 µm. JFD is highly hygroscopic, easily deliquesces to an amorphous glass solid and changes subsequently to another crystal form under an elevated moisture/temperature condition. Similar physical instability was also observed in real-time CheqSol solubility assay. pK(a) (7.49 ± 0.01), log P (5.10 ± 0.02) and intrinsic solubility (S0) (1.75 µg/ml) at 37 °C of JFD were obtained using potentiometric titration method. Based on these solution-state properties, JFD was estimated to be classified as BCS II, thus its dissolution rate may be an absorption-limiting step. Moreover, JFD was more chemically compatible with dibasic calcium phosphate, mannitol, hypromellose and colloidal silicon dioxide than with lactose and magnesium stearate. Further, JFD exhibited an acceptable pharmacokinetic profiling in beagle dogs and the pharmacokinetic parameters T(max), C(max), AUC(0-t) and absolute bioavailability were 1.60 ± 0.81 h, 0.78 ± 0.47 µg/ml, 3.77 ± 1.85 µg·h/ml and 52.30 ± 19.39%, respectively. The preformulation characterization provides valuable information for further development of oral administration of JFD.

Novel ethylcellulose-coated pellets for controlled release of metoprolol succinate without lag phase: characterization, optimization and in vivo evaluation.

The objective of this study was to develop a novel ethylcellulose (EC)-coated pellet with partial active dose as a pore former for the controlled release of water-soluble metoprolol succinate (MS) without an initial lag phase (slow/non-drug release phase). MS-layered cores with a high drug-loading efficiency (97%, w/w), a smooth surface, and an acceptable level of resistance to abrasion were first obtained by spraying a concentrated drug solution (60% w/w at 70 °C) on non-pareils in the absence of other binders. The presence of the drug in an EC coating solution significantly improved the coating process by reducing pellet stickiness. Central composite design and response surface methodology was employed to optimize and explore the effect of pore former MS level (X1) and EC coating level (X2) on the drug release. The pore former level had a positive effect on the MS release and the coating level had a negative effect. The level of X1 and X2 of the optimization were 17% and 23%, respectively, and the cumulative percent of MS released within 1 h was up to 9.2%. Accordingly, the initial lag phase associated with in vitro drug release from EC-coated pellets was absent when MS drug was used as a pore former, which was further confirmed by in vivo drug release in beagle dogs. Thus, a novel approach for the controlled release of MS from coated pellets without lag phase has been successfully developed, which is valuable for the advancement of sustained-release pellets.