In last decade Vitamin B12 (VB12) had been used as carrier for successful delivery of drugs. The focus of the present article is to review the different applications of Vitamin B12 in drug delivery including as an absorption enhancer, as targeting moiety to cancer cells, to increase transepidermal transport across the airway epithelium, to enhance immunoadjuvant properties and as a pH-responsive carrier for improved oral drug delivery of poorly permeable drug molecules. Vitamin B12 has self intestinal uptake pathway by which it can be transported to the systemic circulation. In the present article the role of intrinsic factor in the absorption of Vitamin B12 is also discussed in depth to learn about the different approaches, processes, and mechanisms involved in improving the absorption of drugs having poor permeability. Continued research and optimization of formulations based on nanoparticles modified or conjugated with active moiety like Vitamin B12 are expected to lead to a much sought- after non invasive delivery of peptide based therapeutics. This review has been designed to summarize the research studies and applications of vitamin B12 used for improving drug delivery of drug substances by oral route due to its own intestinal uptake pathway. This review can be of great importance to researchers working in the field of drug delivery of peptide or protein based therapeutics and drug molecules having poor oral bioavailability.

中文翻译：

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维生素B12在药物输送中的应用研究进展。

在过去的十年中，维生素B12（VB12）被用作成功递送药物的载体。本文的重点是综述维生素B12在药物递送中的不同应用，包括作为吸收增强剂，作为癌细胞的靶向部分，增加跨气道上皮的经皮运输，增强免疫佐剂特性以及对pH敏感用于改善渗透性差的药物分子的口服药物递送的载体。维生素B12具有自我肠道吸收的途径，可以将其运输到体循环。在本文中，还深入讨论了内在因素在维生素B12吸收中的作用，以了解与改善通透性差的药物吸收有关的不同方法，过程和机制。预计将继续对基于纳米颗粒进行修饰或与活性部分（如维生素B12）缀合的制剂进行研究和优化，这将导致非侵入性地开发基于肽的治疗药物。这篇综述旨在总结维生素B12的研究和应用，该维生素B12由于其自身的肠道吸收途径，可通过口服途径改善药物的药物输送。该综述对于从事基于肽或蛋白质的治疗药物以及口服生物利用度较差的药物分子的药物输送领域的研究人员而言具有重要意义。这篇综述旨在总结维生素B12的研究和应用，该维生素B12由于其自身的肠道吸收途径，可通过口服途径改善药物的药物输送。该综述对于从事基于肽或蛋白质的治疗药物以及口服生物利用度较差的药物分子的药物输送领域的研究人员而言具有重要意义。这篇综述旨在总结维生素B12的研究和应用，该维生素B12由于其自身的肠道吸收途径，可通过口服途径改善药物的药物输送。该综述对于从事基于肽或蛋白质的治疗药物以及口服生物利用度较差的药物分子的药物输送领域的研究人员而言具有重要意义。