Yeast capsules for targeted delivery: the future of nanotherapy?

Recent Advances in Biomedical Nanotechnology Related to Natural Products

Natural product processing via nanotechnology has opened the door to innovative and significant applications in medical fields. On one hand, plants-derived bioactive ingredients such as phenols, pentacyclic triterpenes and flavonoids exhibit significant pharmacological activities, on another hand, most of them are hydrophobic in nature, posing challenges to their use. To overcome this issue, nanoencapsulation technology is employed to encapsulate these lipophilic compounds and enhance their bioavailability. In this regard, various nano-sized vehicles, including degradable functional polymer organic compounds, mesoporous silicon or carbon materials, offer superior stability and retention for bioactive ingredients against decomposition and loss during delivery as well as sustained release. On the other hand, some naturally occurring polymers, lipids and even microorganisms, which constitute a significant portion of Earth's biomass, show promising potential for biomedical applications as well. Through nano-processing, these natural products can be developed into nano-delivery systems with desirable characteristics for encapsulation a wide range of bioactive components and therapeutic agents, facilitating in vivo drug transport. Beyond the presentation of the most recent nanoencapsulation and nano-processing advancements with formulations mainly based on natural products, this review emphasizes the importance of their physicochemical properties at the nanoscale and their potential in disease therapy.

Advances in Oral Drug Delivery Systems: Challenges and Opportunities

The oral route is the most preferred route for systemic and local drug delivery. However, the oral drug delivery system faces the harsh physiological and physicochemical environment of the gastrointestinal tract, which limits the bioavailability and targeted design of oral drug delivery system. Innovative pharmaceutical approaches including nanoparticulate formulations, biomimetic drug formulations, and microfabricated devices have been explored to optimize drug targeting and bioavailability. In this review, the anatomical factors, biochemical factors, and physiology factors that influence delivering drug via oral route are discussed and recent advance in conventional and novel oral drug delivery approaches for improving drug bioavailability and targeting ability are highlighted. We also address the challenges and opportunities of oral drug delivery systems in future.

Yeast as carrier for drug delivery and vaccine construction

Yeast has been employed as an effective derived drug carrier as a unicellular microorganism. Many research works have been devoted to the encapsulation of nucleic acid compounds, insoluble small molecule drugs, small molecules, liposomes, polymers, and various nanoparticles in yeast for the treatment of disease. Recombinant yeast-based vaccine carriers (WYV) have played a major role in the development of vaccines. Herein, the latest reports on the application of yeast carriers and the development of related research are summarized, a conceptual description of gastrointestinal absorption of yeast carriers, as well as the various package forms of different drug molecules and nanoparticles in yeast carriers are introduced. In addition, the advantages and development of recombinant yeast vaccine carriers for the disease, veterinary and aquaculture applications are discussed. Moreover, the current challenges and future directions of yeast carriers are proposed.

Strategies to improve insulin delivery through oral route: A review

Diabetes mellitus is found to be among the most suffered and lethal diseases for mankind. Diabetes mellitus type-1 is caused by the demolition of pancreatic islets responsible for the secretion of insulin. Insulin is the peptide hormone (anabolic] that regulates the metabolism of carbohydrates, fats, and proteins. Upon the breakdown of the natural process of metabolism, the condition leads to hyperglycemia (increased blood glucose levels]. Hyperglycemia demands outsourcing of insulin. The subcutaneous route was found to be the most stable route of insulin administration but faces patient compliance problems. Oral Insulin delivery systems are the patient-centered and innovative novel drug delivery system, eliminating the pain caused by the subcutaneous route of administration. Insulin comes in contact across various barriers in the gastrointestinal tract, which has been discussed in detail in this review. The review describes about the different bioengineered formulations, including microcarriers, nanocarriers, Self-Microemulsifying drug delivery systems (SMEDDs), Self-Nanoemulsifying drug delivery systems (SNEDDs), polymeric micelles, cochleates, etc. Surface modification of the carriers is also possible by developing ligand anchored bioconjugates. A study on evaluation has shown that the carrier systems facilitate drug encapsulation without tampering the properties of insulin. Carrier-mediated transport by the use of natural, semi-synthetic, and synthetic polymers have shown efficient results in drug delivery by protecting insulin from harmful environment. This makes the formulation readily acceptable for a variety of populations. The present review focuses on the properties, barriers present in the GI tract, overcome the barriers, strategies to formulate oral insulin formulation by enhancing the stability and bioavailability of insulin.

Biomimetic and bioinspired strategies for oral drug delivery

Oral drug delivery remains the most preferred approach due to its multiple advantages. Recently there has been increasing interest in the development of advanced vehicles for oral delivery of different therapeutics. Among them, biomimetic and bioinspired strategies are emerging as novel approaches that are promising for addressing biological barriers encountered by traditional drug delivery systems. Herein we provide a state-of-the-art review on the current progress of biomimetic particulate oral delivery systems. Different biomimetic nanoparticles used for oral drug delivery are first discussed, mainly including ligand/antibody-functionalized nanoparticles, transporter-mediated nanoplatforms, and nanoscale extracellular vesicles. Then we describe bacteria-derived biomimetic systems, with respect to oral delivery of therapeutic proteins or antigens. Subsequently, yeast-derived oral delivery systems, based on either chemical engineering or bioengineering approaches are discussed, with emphasis on the treatment of inflammatory diseases and cancer as well as oral vaccination. Finally, bioengineered plant cells are introduced for oral delivery of biological agents. A future perspective is also provided to highlight the existing challenges and possible resolution toward clinical translation of currently developed biomimetic oral therapies.

Targeted Delivery of Cisplatin-Derived Nanoprecursors via a Biomimetic Yeast Microcapsule for Tumor Therapy by the Oral Route

Targeted therapy via the patient-friendly oral route remains the holy grail of chemotherapy for cancer. Herein we report a yeast-derived platform for targeted oral delivery of cisplatin (CDDP) that is one of the most effective drugs for chemotherapy of various types of cancers. Methods: The optimal conditions were first established to fabricate yeast microcapsules (YCs) with desirable loading capability. Then, CDDP-derived precursor nanoparticles (PreCDDP) were prepared and packaged into YC to produce orally deliverable PreCDDP/YC. The physiochemical properties, in vitro drug release profiles, in vitro antitumor activity, oral targeting capability, in vivo pharmacokinetics, and in vivo efficacy of the YC-based biomimetic delivery system were examined. Results: YCs obtained under the optimized condition showed desirable loading efficiency for quantum dots that were used as a model nanocargo. In vitro experiments demonstrated rapid endocytosis and prolonged retention of YC in macrophages. By electrostatic force-mediated self-deposition, PreCDDP was efficiently loaded into YC. PreCDDP/YC showed potent cytotoxicity in different tumor cells, indicating that PreCDDP loaded in YC maintained its antitumor activity after intracellular release. As compared to CDDP and PreCDDP, orally administered PreCDDP/YC displayed significantly higher bioavailability. Post oral delivery, YC could accumulate in A549 human lung carcinoma xenografts in mice, achieving by monocyte/macrophage-mediated translocation via the lymphatic system. Through this targeting effect, orally administered PreCDDP/YC showed desirable efficacy in A549 xenograft-bearing mice, which was comparable to that of free CDDP administered by intravenous injection. Orally administered free CDDP, however, did not afford antitumor effects. Furthermore, oral treatment with PreCDDP/YC displayed better safety than free CDDP administered via the oral or intravenous route. Conclusions: This biomimetic approach can serve as an effective strategy to develop targeted oral chemotherapies based on CDDP or its derivatives.