Organocatalytic Enantioselective Chloroiminocyclization for the Synthesis of Imidazoline.

Imidazoline is an important scaffold in organic synthesis and a pharmacophore in medicinal chemistry. We apply basic imines as nucleophiles for the catalytic asymmetric chloroiminocyclization to furnish tetrasubstituted stereocenter-containing imidazolines in excellent yields and enantioselectivities. The reaction can be conducted in the polar solvent acetonitrile under concentrated reaction conditions.

Ginsenosides from Panax ginseng as potential therapeutic candidates for the treatment of inflammatory bowel disease.

BACKGROUND: Inflammatory bowel disease (IBD) is characterized by a chronic inflammation of the intestine, which significantly affects patients' quality of life. As a perennial plant with the homology of medicine and food, Panax ginseng is known for its substantial anti-inflammatory effects in various inflammatory disorders. Ginsenosides, the main bioactive compounds of P. ginseng, are recognized for their efficacy in ameliorating inflammation. PURPOSE: Over the past decade, approximately 150 studies have investigated the effects of P. ginseng and ginsenosides on IBD treatment and new issues have arisen. However, there has yet to be a comprehensive review assessing the potential roles of ginsenosides in IBD therapy. METHOD: This manuscript strictly adheres to the PRISMA guidelines, thereby guaranteeing systematic synthesis of data. The research articles referenced were sourced from major scientific databases, including Google Scholar, PubMed, and Web of Science. The search strategy employed keywords such as "ginsenoside", "IBD", "colitis", "UC", "inflammation", "gut microbiota", and "intestinal barrier". For image creation, Figdraw 2.0 was methodically employed. RESULTS: Treatment with various ginsenosides markedly alleviated clinical IBD symptoms. These compounds have been observed to restore intestinal epithelia, modulate cellular immunity, regulate gut microbiota, and suppress inflammatory signaling pathways. CONCLUSION: An increasing body of research supports the potential of ginsenosides in treating IBD. Ginsenosides have emerged as promising therapeutic agents for IBD, attributed to their remarkable efficacy, safety, and absence of side effects. Nevertheless, their limited bioavailability presents a substantial challenge. Thus, efforts to enhance the bioavailability of ginsenosides represent a crucial and promising direction for future IBD research.

Bioceramic scaffolds with two-step internal/external modification of copper-containing polydopamine enhance antibacterial and alveolar bone regeneration capability. / å«é“œèšå¤šå·´èƒºå† å¤–åŒä¿®é¥°æ³•æž„å»ºæŠ—èŒä¿ƒéª¨å†ç”Ÿç”Ÿç‰©é™¶ç“·æ”¯æž¶.

Magnesium-doped calcium silicate (CS) bioceramic scaffolds have unique advantages in mandibular defect repair; however, they lack antibacterial properties to cope with the complex oral microbiome. Herein, for the first time, the CS scaffold was functionally modified with a novel copper-containing polydopamine (PDA(Cu2+|)) rapid deposition method, to construct internally modified (*P), externally modified (@PDA), and dually modified (*P@PDA) scaffolds. The morphology, degradation behavior, and mechanical properties of the obtained scaffolds were evaluated in vitro. The results showed that the CS*P@PDA had a unique micro-/nano-structural surface and appreciable mechanical resistance. During the prolonged immersion stage, the release of copper ions from the CS*P@PDA scaffolds was rapid in the early stage and exhibited long-term sustained release. The in vitro evaluation revealed that the release behavior of copper ions ascribed an excellent antibacterial effect to the CS*P@PDA, while the scaffolds retained good cytocompatibility with improved osteogenesis and angiogenesis effects. Finally, the PDA(Cu2+)-modified scaffolds showed effective early bone regeneration in a critical-size rabbit mandibular defect model. Overall, it was indicated that considerable antibacterial property along with the enhancement of alveolar bone regeneration can be imparted to the scaffold by the two-step PDA(Cu2+) modification, and the convenience and wide applicability of this technique make it a promising strategy to avoid bacterial infections on implants.

Path Analysis of Self-Efficacy, Coping Style and Resilience on Depression in Patients with Recurrent Schizophrenia.

Purpose: Based on the two mediating variables of self-efficacy and coping style, a multiple mediating model was constructed to explore the mechanism by which psychological resilience affects depression in patients with recurrent schizophrenia. Methods: A total of 210 patients with recurrent schizophrenia who were hospitalized in a tertiary hospital in Hunan Province, China, were enrolled. The Connor Davidson Resilience Scale (CD-RISC), Self-rating Depression Scale (SDS), General Self-Efficacy Energy Scale (GSES) and Simplified Coping Style Questionnaire (SCSQ) were used to evaluate resilience, self-efficacy, coping style and depression. Path analysis was performed by constructing a structural equation model, and the mediating effect between variables was verified by the bias-corrected nonparametric percentile bootstrap method. Results: Resilience, self-efficacy and positive coping together explained 53.2% of the variance in depression. (1) The total scores of self-efficacy, coping style, resilience and depression in patients with recurrent schizophrenia were 2.54±0.61, 31.73±9.62, 58.06±17.26 and 50.48±12.55, respectively. (2) Pearson analysis showed that the scores of self-efficacy, positive coping, resilience and depression were significantly correlated with depression (r=-0.24-0.51, P<0.01). (3) The path analysis showed that resilience directly affects depression (ß=-0.401); additionally, resilience indirectly affects depression through self-efficacy (ß=-0.179) and through the chain mediating effect of self-efficacy and positive coping style (ß=-0.024). Conclusion: There is a high incidence of depression in patients with recurrent schizophrenia in China, and intervention is needed. This research revealed that resilience directly affects depression in patients with recurrent schizophrenia and that self-efficacy and positive coping play a part in mediating resilience and depression in patients with recurrent schizophrenia in China. Implementing targeted interventions based on action paths to improve the level of resilience and reduce the incidence of depression has guiding significance in the field of occupational rehabilitation of patients with recurrent schizophrenia.

Modularized bioceramic scaffold/hydrogel membrane hierarchical architecture beneficial for periodontal tissue regeneration in dogs.

BACKGROUND: Destruction of alveolar bone and periodontal ligament due to periodontal disease often requires surgical treatment to reconstruct the biological construction and functions of periodontium. Despite significant advances in dental implants in the past two decades, it remains a major challenge to adapt bone grafts and barrier membrane in surgery due to the complicated anatomy of tooth and defect contours. Herein, we developed a novel biphasic hierarchical architecture with modularized functions and shape based on alveolar bone anatomy to achieve the ideal outcomes. METHODS: The integrated hierarchical architecture comprising of nonstoichiometric wollastonite (nCSi) scaffolds and gelatin methacrylate/silanized hydroxypropyl methylcellulose (GelMA/Si-HPMC) hydrogel membrane was fabricated by digital light processing (DLP) and photo-crosslinked hydrogel injection technique respectively. The rheological parameters, mechanical properties and degradation rates of composite hydrogels were investigated. L-929 cells were cultured on the hydrogel samples to evaluate biocompatibility and cell barrier effect. Cell scratch assay, alkaline phosphatase (ALP) staining, and alizarin red (AR) staining were used to reveal the migration and osteogenic ability of hydrogel membrane based on mouse mandible-derived osteoblasts (MOBs). Subsequently, a critical-size one-wall periodontal defect model in dogs was prepared to evaluate the periodontal tissue reconstruction potential of the biphasic hierarchical architecture. RESULTS: The personalized hydrogel membrane integrating tightly with the nCSi scaffolds exhibited favorable cell viability and osteogenic ability in vitro, while the scratch assay showed that osteoblast migration was drastically correlated with Si-HPMC content in the composite hydrogel. The equivalent composite hydrogel has proven good physiochemical properties, and its membrane exhibited potent occlusive effect in vivo; meanwhile, the hierarchical architectures exerted a strong periodontal regeneration capability in the periodontal intrabony defect models of dogs. Histological examination showed effective bone and periodontal ligament regeneration in the biomimetic architecture system; however, soft tissue invasion was observed in the control group. CONCLUSIONS: Our results suggested that such modularized hierarchical architectures have excellent potential as a next-generation oral implants, and this precisely tuned guided tissue regeneration route offer an opportunity for improving periodontal damage reconstruction and reducing operation sensitivity.

Mediating Effect of Self-Efficacy on the Relationship Between Perceived Social Support and Resilience in Patients with Recurrent Schizophrenia in China.

Purpose: To explore the mediating effect of self-efficacy on the relationship between perceived social support and resilience in patients with recurrent schizophrenia in China. Patients and Methods: In this cross-sectional study, a total of 176 patients with recurrent schizophrenia who were hospitalized in a tertiary hospital in Hunan Province, China, completed a general data questionnaire, the Connor Davidson Resilience Scale (CD-RISC), the Perceived Social Support Scale (PSSS) and the General Self-Efficacy Energy Scale (GSES). Results: Among the 176 patients, the mean GSES score was 2.02±0.61, the mean PSSS score was 56.77±14.61, and the mean CD-RISC score was 58.06±17.26. Self-efficacy played a partial mediating role between social support and resilience, and the mediating effect accounted for 42.56% of the total effect. Conclusion: The resilience level of patients with recurrent schizophrenia in China is moderate and needs to be improved. This research revealed that self-efficacy played a part in mediating perceived social support and resilience in patients with recurrent schizophrenia in China. Perceived social support can indirectly affect resilience in patients with recurrent schizophrenia through self-efficacy. Comprehensive interventions in perceived social support and self-efficacy would help to improve the resilience of patients with recurrent schizophrenia.

Autistic children's age difference in affiliate stigma and resilience of their parents in China: A cross-sectional study.

BACKGROUND: Parents of children with Autism Spectrum Disorders (ASD) experience high levels of stigma, especially in China where the culture is shame socialized. Resilience can help overcome stigma; while parent characteristics predict resilience, other factors may also be significant such as the child's age. OBJECTIVE: The study sought to identify the differences in affiliate stigma and resilience among Chinese parents of children with ASD according to the child's age, and to determine whether the levels of resilience and experience of stigma are related. METHODS: A cross-sectional survey of 184 parents of children with ASD was conducted. Affiliate stigma and resilience were measured using the Chinese version of the 22-item Affiliate Stigma Scale and the Chinese version of the Connor-Davidson Resilience Scale. Differences were examined by using regression and correlation analysis. RESULTS: Parents of school-age children experienced more affiliate stigma than parents of preschoolers, but there was no difference in resilience when other factors were controlled. CONCLUSIONS: Considering the child's age is important to understand affiliate stigma and resilience, particularly where resilience is protective and could inform the design of support strategies for preschooler parents.

3D printed bioceramic scaffolds: Adjusting pore dimension is beneficial for mandibular bone defects repair.

Bioceramic scaffolds for repairing mandibular bone defects have considerable effects, whereas pore architecture in porous scaffolds on osteogenesis in specific structures is still controversial. Herein 6 mol% magnesium-substituted calcium silicate scaffolds were fabricated with similar porosity (∼58%) but different cylindrical pore dimensions (Ø 480, 600, and 720 µm) via digital light processing-based three-dimensional (3D) printing technique. The mechanical properties, bioactive ion release, and bio-dissolution of the bioceramic scaffolds were evaluated in vitro, and the facilitation of scaffolds on bone formation was investigated after implanting in vivo. The results showed that as the pore dimension increased, the scaffolds indicated similar surface microstructures, but their compressive strength was enhanced gradually. There was no significant difference in vitro bio-dissolution between the 480 and 600 µm groups, whereas the 720 µm group showed a much slower dissolution and ion release. Interestingly, the two-dimensional/three-dimensional (2D/3D) micro-CT reconstruction analysis of rabbits' mandibular bone defects model showed that the 600 µm group exhibited evidently higher ratio of the newly formed bone volume to total volume (BV/TV) and trabecular number (Tb. N) values and lower ratio of the scaffolds residual volume to total volume (RV/TV) compare to the other two sizes. Furthermore, the histological analysis also revealed a considerably higher new bone ingrowth rate in the 600 µm group than the other two groups at 4-12 weeks post-implantation. Totally, it is proved from these experimental studies that the DLP-based accurately fabricated calcium (Ca) silicate bioceramic scaffolds with appropriate pore dimensions (i.e., 600 µm in pore size) are promising to guide new bone ingrowth and thus accelerate the regeneration and repair of cranial maxillofacial or periodontal bone defects.

Catalytic Enantioselective Halocyclizations to Access Benzoxazepinones and Benzoxazecinones.

We report a catalytic asymmetric halocyclization protocol to furnish benzoxazepinones and benzoxazecinones using (DHQ)2PHAL as the catalyst. Various halogenated benzoxazepinones and benzoxazecinones were achieved in excellent yields and enantioselectivities under mild conditions. A cocrystal structure of the substrate and the catalyst was studied.

Relationship between stressful life events, coping styles, and schizophrenia relapse.

This study aimed to explore the relationship between stressful life events, coping styles, and schizophrenia relapse. The sample for this study included 248 patients with schizophrenia from a psychiatric outpatient clinic in Hunan Province, China. Stressful life events, occurrence of schizophrenia relapse, and coping style were assessed by the Scale for the Social Readjustment Rating, Brief Psychiatric Rating Scale, and Simplified Coping Style Questionnaire, respectively. Spearman correlation analysis and binary logistic regression analysis were adopted to explore the relationships among coping styles, schizophrenia relapse, and stressful life events. Stressful life events and negative coping exhibited significant positive association with schizophrenia relapse, while positive coping exhibited a significant negative association with schizophrenia relapse. Stressful life events and positive coping exerted significant effects on schizophrenia relapse, while negative coping did not. We also found that both positive coping and negative coping have moderating effects on the relationship between stressful life events and schizophrenia relapse, but the relationship is weak. The study highlighted the importance of interventions designed to reduce stressful life events, promote positive coping, and address negative coping in patients with schizophrenia.

Interleukin-17 induces pyroptosis in osteoblasts through the NLRP3 inflammasome pathway in vitro.

OBJECTIVE: Interleukin-17 (lL-17), a pro-inflammatory cytokine produced by Th17 cells, is also considered to play an important role in bone metabolism, but the exact mechanism of bone destruction remains unclear. In this study, we explored whether IL-17 could induce osteoblasts pyroptosis in vitro. METHODS: The murine primary osteoblasts were isolated from the calvarial bones of mice. The proliferation of osteoblasts was evaluated by cell counting kit-8 (CCK-8) assay. The mRNA levels of NOD-like receptor family pyrin domain containing 3 (NLRP3), apoptosis associated speck like protein containing a card (ASC), caspase-1, gasdermin-D (GSDMD), IL-1ß and receptor activator of nuclear factor-kappa B ligand (RANKL) were measured by real-time quantitative PCR. Pyroptosis after IL-17 treatment was evaluated by lactate dehydrogenase (LDH) Release Assay Kit and the morphological characteristics of osteoblasts were observed via Scanning Electron Microscopy (SEM). Pyroptosis associated proteins, cleaved IL-1ß and RANKL were evaluated through western blot. The release of IL-1ß and RANKL was measured by ELISA. In addition, calcium nodule was tested by alizarin red staining. RESULTS: High concentration IL-17 (100 ng/mL) could affect the proliferation of osteoblasts, promote the gene expression of NLRP3, caspase-1, GSDMD, IL-1ß and RANKL. In contrast to control group, osteoblasts treated with IL-17 had the appearance of numerous pores, swelling and rupture. Also, the release of LDH, IL-1ß and RANKL increased in the presence of IL-17. However, inhibition of NLRP3 prevented activation of the NLRP3 inflammasome, thereby restoring osteoblasts morphology and function. CONCLUSION: IL-17 induced osteoblasts pyroptosis, and the pyroptosis of osteoblasts may prompt the release of IL-1ß and RANKL,which may further contribute to disruption of bone metabolism. Besides, the NLRP3 inflammasome pathway was involved in the pyroptosis of osteoblasts.

Synthesis and cytotoxic evaluation of halogenated α-exo-methylene-lactones.

α-exo-Methylene-γ-butyrolactones and α-exo-methylene-δ-valerolactones constitute an important group of natural and bioactive products. A simple and general protocol of halolactonization of dienoic acids to obtain various α-exo-methylene-lactones in excellent yields is described. The resulting halogenated α-exo-methylene-lactones were found to exhibit potent cytotoxic activities.

Enantioselective Halolactonizations Using Amino-Acid-Derived Phthalazine Catalysts.

Amino-acid-derived phthalazine catalysts have been designed and synthesized for enantioselective halolactonization of prochiral dienoic acids. The scope of the reaction is evidenced by 17 examples of spiro α-exo-methylene-halolactones with up to 99.8% enantiomeric excess. The resulting enantio-enriched spiro halolactone products are found to exhibit potent antitumor effects. In addition, both antipodes of products with equally excellent enantioselevity could be obtained since a pair of enantiomeric catalysts is guaranteed.

Bioequivalence Study Methods with Pharmacokinetic Endpoints for Topical Ophthalmic Corticosteroid Suspensions and Effects of Subject Demographics.

PURPOSE: To establish bioequivalence for topical ophthalmic corticosteroid suspensions, some of U.S. product-specific guidances (PSGs) for generic drug products recommend evaluation of aqueous humor (AH) pharmacokinetics (PK). However, the AH PK study is complex because the relationships among AH PK, subject demographics, ocular anatomy, physiology and the compounds' physicochemical characteristics are not well understood. The objective of this research is to provide an overview of the in vivo human AH studies submitted to the U.S. Food and Drug Administration (FDA) for ophthalmic corticosteroid suspensions and to investigate the impact of subject demographics on the human AH PK. METHODS: We summarized demographic data, sampling time points, sample size per time point and PK parameters to investigate correlations in the studies submitted to the FDA. RESULTS: In the evaluation of subject-specific covariates, the area under the concentration-time curves (AUC) and maximum concentrations (Cmax) were significantly different among ethnicities and age groups. Gender was not primarily associated with differences in AH PK. CONCLUSIONS: Our results suggest that the difference in ethnicity and age of the study population play an important role in the AH PK profiles of topical ophthalmic corticosteroid suspensions. Considering the subject-specific covariate effects in designing bioequivalence studies with AH PK endpoints could reduce bias from covariate imbalance and help identify true effects of formulation differences.

Enantioselective Bromolactonization of Deactivated Olefinic Acids.

A novel enantioselective bromolactonization of α,ß-unsaturated ketones using bifunctional amino-urea catalysts has been developed. The scope of the reaction is evidenced by 23 examples of halolactones bearing various functionalities with up to 99% yield and 99:1 er. Unlike typical urea catalysts that require electron-deficient substituents to enhance the hydrogen bond strength, it is interesting to realize that electron-rich ureas are essential for high enantioselectivity in this case. Moreover, experimental data reveals that the halolactone compounds exhibit considerable anti-inflammatory effects on LPS-induced RAW 264.7 cells.

S1P/S1PR3 signaling mediated proliferation of pericytes via Ras/pERK pathway and CAY10444 had beneficial effects on spinal cord injury.

Pericytes have long been regarded merely to maintain structural and functional integrity of blood-brain barrier (BBB). Nevertheless, it has also been identified as a component of scar-forming stromal cells after spinal cord injury (SCI). In process of enlargement of spinal cavity after SCI, the number of pericytes increased and outnumbered astrocytes. However, the mechanism of proliferation of pericytes remains unclear. Sphingosine-1-phosphate (S1P) has been reported to play important roles in the formation of glia scar, but previous studies had paid more attention to the astrocytes. The present study aimed to observe the effects of S1P and S1P receptors (S1PRs) on proliferation of pericytes and investigate the underlying mechanism. By double immunostaining, we found that the number of PDGFRß-positive pericytes was gradually increased and sealed the cavity, which surrounded by reactive astrocytes. Moreover, the subtype of S1PR3 was found to be induced by SCI and mainly expressed on pericytes. Further, by use of CAY10444, an inhibitor of S1PR3, we showed that S1P/S1PR3 mediated the proliferation of pericytes through Ras/pERK pathway. Moreover, CAY10444 was found to have the effects of enhancing neuronal survival, alleviating glial scar formation, and improving locomotion recovery after SCI. The results suggested that S1P/S1PR3 might be a promising target for clinical therapy for SCI.

Common Deficiencies of in vitro Binding Bioequivalence (BE) Studies Submitted in Abbreviated New Drug Applications (ANDAs).

There are several drug products that bind phosphate or bile acid in the gastrointestinal (GI) tract to exert their therapeutic efficacy. In vitro binding studies are used to assess bioequivalence (BE) of these products. The objective of this study is to identify the common deficiencies in Abbreviated New Drug Applications (ANDAs) for these products. Deficiencies were compiled from ANDAs containing in vitro binding BE studies. The deficiencies were classified into eight categories: Pre-Study Method Validation, During-Study Sample Analysis, Study Design, Study Procedure, Dissolution/Disintegration, Analytical Site Inspection, Data Submission, and Formulations. Within each category, additional subcategories were defined to characterize the deficiencies. A total of 712 deficiencies from 95 ANDAs for 11 drug products were identified and included in the analysis. The four categories with the most deficiencies were During-Study Sample Analysis (27.8%), Pre-Study Method Validation (17.3%), Data Submission (16.7%), and Study Design (15.7%). For the During-Study Sample Analysis category, failure to submit complete raw data or analytical runs ranked as the top deficiency (32.8%). For the Study Design category, using an unacceptable alternate study design (26.8%) was the most common deficiency. Within this category, other commonly occurring deficiencies included incorrect/insufficient number of absorbent concentrations, failure to pre-treat drug product with acid, insufficient number of replicates in study, incorrect calculation of k1 and k2 values, incorrect dosage form or pooled samples used in the study, and incorrect pH of study medium. The review and approval of these products may be accelerated if these common deficiencies are addressed in the original ANDA submissions.

LncRNA SNHG5 regulates imatinib resistance in chronic myeloid leukemia via acting as a CeRNA against MiR-205-5p.

Imatinib resistance has become a major obstacle for the treatment of chronic myeloid leukemia (CML). The present study aimed to investigate the effects of the long non-coding RNA, SNHG5 on imatinib resistance in CML and explored the underlying mechanisms. The quantitative real-time PCR results showed that SNHG5 and ABCC2 expressions were up-regulated in the isolated peripheral blood cells of the CML patients when compared with healthy controls, and SNHG5 expression levels was positively correlated with ABCC2 in CML patients. In vitro studies showed that the expressions of SNHG5 and ABCC2 were up-regulated in imatinib resistant cells (K562-R) when compared to K562 cells. Bioinformatics analysis showed the interaction between SNHG5 and miR-205-5p, which was further confirmed by luciferase reporter assay and RNA immune-precipitation in K562 cells. Overexpression of SNHG5 suppressed the expression of miR-205-5p and the expression of SNHG5 was negatively correlated with the miR-205-5p expression in CML patients. In addition, ABCC2 was predicted as a downstream target of miR-205-5p, which was further confirmed by the luciferase reporter assay in K562-R cells, and overexpression of miR-205-5p suppressed the expression of ABCC2 in K562-R cells. In vitro functional assay showed that overexpression of SNHG5 in K562 cells increased imatinib resistance and knock-down of SNHG5 reduced the imatinib resistance in K562-R cells. Further experiments showed that SNHG5 promotes imatinib resistance through regulating ABCC2. Taken together, SNHG5 promotes imatinib resistance in CML via acting as a competing endogenous RNA against miR-205-5p.

In vitro Approaches to Support Bioequivalence and Substitutability of Generic Proton Pump Inhibitors via Nasogastric Tube Administration.

Administration of proton pump inhibitors (PPIs) through nasogastric tubes may present risks. If the PPI drug products are not prepared properly, clogging or obstruction of nasogastric tubes can pose a safety concern. In addition, the integrity of the enteric coating of the drug product may be damaged resulting in reduced bioavailability of the active moiety. From the perspective of administration of generic PPIs when compared to the reference drug product, differences in formulation can potentially result in a greater relative risk for the generic drug product. As part of the assessment of bioequivalence, the Office of Generic Drugs (OGD) has developed a suite of in vitro testing to compare the delivery of the generic and reference products via nasogastric tubes. These in vitro tests assess essential attributes associated with the likelihood of clogging and maintenance of the enteric coating. These in vitro tests include studies evaluating sedimentation, granule size distribution, drug recovery, and acid resistance. One of the challenges is that while the administration of PPIs through nasogastric tubes is common in clinical practice, this issue is not uniformly addressed in the FDA approved label of the reference drug products. This paper discusses the design and rationale for in vitro testing of PPI formulations with respect to bioequivalence via nasogastric tube administration and in addition, it summarizes commonly occurring deficiencies in the in vitro nasogastric tube testing of 14 recent Abbreviated New Drug Applications (ANDA) submitted for five generic PPI drug products.

Analysis of Non-Pivotal Bioequivalence Studies Submitted in Abbreviated New Drug Submissions for Delayed-Release Drug Products.

The US FDA's rule on "Requirements for Submission of Bioequivalence Data" requiring submission of all bioequivalence (BE) studies conducted on the same formulation of the drug product submitted for approval was published in Federal Register in January 2009. With the publication of this rule, we evaluated the impact of data from non-pivotal BE studies in assessing BE and identified the reasons for failed in vivo BE studies for generic oral delayed-release (DR) drug products only. We searched the Agency databases from January 2009 toDecember 2016 to identify Abbreviated New Drug Applications (ANDAs) submitted for DR drug products containing non-pivotal BE studies. Out of 202 ANDAs, 43 ANDAs contained 102 non-pivotal BE studies. Forty-nine non-pivotal BE studies were conducted on the to-be-marketed (TBM) formulation and 53 were conducted on formulations different from the TBM formulation. These experimental formulations primarily differed in the ratio of components of the enteric coating layer and/or amount (i.e., %w/w) of enteric coating layer. Of the 49 non-pivotal BE studies conducted on the TBM formulation, 41 failed to meet the BE acceptance criteria. The majority of failed non-pivotal BE studies on the TBM DR generic products had insufficient power, which was expected as these studies are exploratory in nature and not designed to have adequate power to pass the BE statistical criteria. In addition, among the failed non-pivotal BE studies on the TBM DR generic products, the most commonly failing pharmacokinetic parameter was Cmax. The data from these non-pivotal BE studies indicate that inadequate BE study design can lead to failure of the BE on the same formulation. Also, the non-pivotal BE studies on formulations different from the TBM formulation help us link the formulation design to the product performance in vivo. 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.