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Oral administration is the most simple, noninvasive, convenient treatment. With the increasing demands on the targeted drug delivery, the traditional oral treatment now is facing some challenges: 1) biologics how to implement the oral treatment and ensure the bioavailability is not lower than the subcutaneous injections; 2) How to achieve targeted therapy of some drugs in the gastrointestinal tract? Based on these two issues, drug delivery microrobots have shown great application prospect in oral drug delivery due to their characteristics of flexible locomotion or driven ability. Therefore, this paper summarizes various drug delivery microrobots developed in recent years and divides them into four categories according to different driving modes: magnetic-controlled drug delivery microrobots, anchored drug delivery microrobots, self-propelled drug delivery microrobots and biohybrid drug delivery microrobots. As oral drug delivery microrobots involve disciplines such as materials science, mechanical engineering, medicine, and control systems, this paper begins by introducing the gastrointestinal barriers that oral drug delivery must overcome. Subsequently, it provides an overview of typical materials involved in the design process of oral drug delivery microrobots. To enhance readers' understanding of the working principles and design process of oral drug delivery microrobots, we present a guideline for designing such microrobots. Furthermore, the current development status of various types of oral drug delivery microrobots is reviewed, summarizing their respective advantages and limitations. Finally, considering the significant concerns regarding safety and clinical translation, we discuss the challenges and prospections of clinical translation for various oral drug delivery microrobots presented in this paper, providing corresponding suggestions for addressing some existing challenges.

Abstract Staphylococcal Enterotoxin C2 (SEC2), a classical superantigen, is an antitumor immunotherapy agent. However, the injectable formulation of SEC2 limits its clinical application. Here, it is reported that oral administration of SEC2 activates the intestinal immune system and benefits intestinal health in a mouse model. These results indicate that intact SEC2 is detected in the stomach, intestine, and serum after oral administration. Continuous oral administration of SEC2 activates immune cells in gut‐associated lymphoid tissues, promoting extensive differentiation and proliferation of CD4+ and CD8+ T cells and CD19+ B cells, leading to increased production of cytokines and secretory immunoglobulin A. SEC2 also enhances intestinal barrier function, as demonstrated by an increased villus length/crypt depth ratio and elevated expression of mucins and tight junction proteins. Additionally, SEC2 indirectly influenced gut microbiota, reinforcing potential probiotics and short‐chain fatty acid synthesis. Enhanced differentiation of T and B cells in the spleen, coupled with elevated serum interleukin‐2 levels, suggests systemic immune enhancement following oral administration of SEC2. These findings provide a scientific basis for the development of SEC2 as an oral immunostimulant for immune enhancement and anti‐tumor immunotherapy.

Abstract The objective was to evaluate the effect of oral administration of strontium (Sr) on the regeneration of a critical bone defect. Twenty Wistar rats were divided into two groups, assessed at 15 and 60 days postoperatively: GSr - oral administration of Sr; and CG - without oral administration of Sr. At 15 and 60 days, blood was collected to measure Sr and calcium (Ca), and the calvaria was removed for histomorphological and histomorphometric analyses. Sr+2 plasmatic concentrations were higher in GSr than in CG. The dosage of Ca+2 showed a small increase in the CG about the GSr. In all evaluated groups, new bone formation was restricted to the edges of the defect, and the residual area was filled with fibrous connective tissue. The oral administration of Sr associated with HA microspheres substituted by the metal, in a concentration of 23 mol%, did not affect the formation of the osteoid matrix.

Oral delivery of an inexpensive COVID-19 (coronavirus disease 2019) vaccine could dramatically improve immunization rates, especially in low- and middle-income countries. Previously, we described a potential universal COVID-19 vaccine, rLVS ΔcapB/MN, comprising a replicating bacterial vector, LVS (live vaccine strain) ΔcapB, expressing the highly conserved SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) membrane and nucleocapsid (N) proteins, which, when administered intradermally or intranasally, protects hamsters from severe COVID-19-like disease after high-dose SARS-CoV-2 respiratory challenge. Here, we show that oral administration of the vaccine also protects against high-dose SARS-CoV-2 respiratory challenge; its protection is comparable to that of intradermal, intranasal, or subcutaneous administration. Hamsters were protected against severe weight loss and lung pathology and had reduced oropharyngeal and lung virus titers. Protection against weight loss and histopathology by the vaccine, which in mice induces splenic and lung cell interferon gamma in response to N protein stimulation, was correlated in hamsters with pre-challenge serum anti-N TH1-biased IgG (IgG2/3). Thus, rLVS ΔcapB/MN has potential as an oral universal COVID-19 vaccine. IMPORTANCE The COVID-19 pandemic continues to rage into its fourth year worldwide. To protect the world's population most effectively from severe disease, hospitalization, and death, a vaccine is needed that is resistant to rapidly emerging viral variants of the causative agent SARS-CoV-2, inexpensive to manufacture, store, and transport, and easy to administer. Ideally, such a vaccine would be capable of oral administration, especially in resource-poor countries of the world where there are shortages of needles, syringes and trained personnel to administer injectable vaccines. Here, we show that oral administration of a bacterium-vectored vaccine meeting all these criteria protects naturally susceptible Syrian hamsters from severe COVID-19-like disease, including severe weight loss and lung pathology, after high-dose SARS-CoV-2 respiratory challenge. As the vaccine is based upon inducing immunity to highly conserved SARS-CoV-2 membrane and nucleocapsid proteins, as opposed to the rapidly mutating Spike protein, it should remain resistant to newly emerging SARS-CoV-2 variants.

Abstract Radiation-induced intestinal injury is the most common side effect during radiotherapy of abdominal or pelvic solid tumors, significantly impacting patients’ quality of life and even resulting in poor prognosis. Until now, oral application of conventional formulations for intestinal radioprotection remains challenging with no preferred method available to mitigate radiation toxicity in small intestine. Our previous study revealed that nanomaterials derived from spore coat of probiotics exhibit superior anti-inflammatory effect and even prevent the progression of cancer. The aim of this work is to determine the radioprotective effect of spore coat (denoted as spore ghosts, SGs) from three clinically approved probiotics (B.coagulans, B.subtilis and B.licheniformis). All the three SGs exhibit outstanding reactive oxygen species (ROS) scavenging ability and excellent anti-inflammatory effect. Moreover, these SGs can reverse the balance of intestinal flora by inhibiting harmful bacteria and increasing the abundance of Lactobacillus. Consequently, administration of SGs significantly reduce radiation-induced intestinal injury by alleviating diarrhea, preventing X-ray induced apoptosis of small intestinal epithelial cells and promoting restoration of barrier integrity in a prophylactic study. Notably, SGs markedly improve weight gain and survival of mice received total abdominal X-ray radiation. This work may provide promising radioprotectants for efficiently attenuating radiation-induced gastrointestinal syndrome and promote the development of new intestinal predilection.

Introduction. The development and registration of antiviral drugs is an urgent task. Flavonoids, in particular, luteolin-7-glycoside (cinaroside, luteolin-7-O-glycoside) demonstrate high broad-spectrum antiviral activity in vitro, and the industrial regulations for the production of luteolin-7-glycoside from the leaves of holly willow have already been developed at the VILAR. One of the problems with the introduction of flavonoids into medical practice is their low bioavailability and intensive biotransformation. Existing publications provide contradictory data on the pharmacokinetics of luteolin-7-glycoside, and therefore our own research was conducted.Aim. To develop a methodology for the quantitative analysis of luteolin-7-glycoside and its metabolites in blood plasma and to test it on laboratory animals.Materials and methods. Animal experiments were carried out in accordance with the requirements of the "Guidelines for conducting preclinical studies of medicines". To develop a method of analysis and further clarify the time intervals of blood sampling, time points were analyzed: 30, 60 minutes, 2, 4, 8, 24 hours after administration of the test substance. Tubes with citrate blood of laboratory animals were centrifuged at 2000 rpm for 10 minutes. The plasma was placed in an Eppendorf-type test tube, frozen and stored at –20 °C until chromatographic analysis was performed. Blood plasma sample preparation was carried out by precipitation with methyl alcohol, the supernatant was chromatographically separated on a column Luna® 5 µm C18 column 100 Å 250 × 4.6 mm in a gradient mode in a water-acetonitrile system and a modifier – 0.2 % formic acid. The metabolites were identified by high-performance liquid chromatography with mass spectrometric detection. To do this, the spectral characteristics of the peaks that appeared on the chromatograms of blood plasma samples after oral administration of luteolin-7-glycoside were interpreted. The concentration of the analyzed substances was assessed by the internal standard method, which was rutin. To determine the concentration of luteolin, a standardized luteolin substance was used as a standard sample, the concentration of the remaining metabolites was estimated in terms of luteolin.Results and discussion. It was found that after oral administration of luteolin-7-glycoside in starch paste to laboratory animals, native luteolin-7-glycoside was not detected in blood plasma. The main metabolites were luteolin-diglucuronide and luteolin-glucuronide, their maximum plasma concentrations are about three times higher than luteolin and methyllyuteolin-diglucuronide. The results are compared with data from other studies.Conclusion. The absence of native luteolin-7-glycoside in blood plasma after oral administration makes it necessary to seriously reconsider the relevance of the conclusions obtained during studies of its activity in vitro. However, in the presence of antiviral activity in vivo, there is an urgent need for further research to establish the real mechanisms of action of this medicinal substance.