Spanlastics: Versatile Elastic Vesicles for Advanced Drug Delivery

Background: Spanlastics, also known as elastic niosomes, represent a modified advancement in the field of colloidal system-based drug delivery carriers over the past decade. The term “Spanlastics” was first introduced in 2011 by Kakkar and Kaur, notably for ocular delivery of ketoconazole, marking the beginning of this innovative delivery system. These systems comprise a non-ionic surfactant (Span) and an “edge activator” which imparts high elasticity to the vesicles, making them deformable and allowing them to traverse narrow intercellular spaces, thereby enhancing drug permeation across biological membranes. Spanlastics are being explored as potential drug carriers for a vast spectrum of drugs via myriad administration routes. Objective: This review provides a comprehensive understanding of spanlastics by exploring their various methods of preparation and examining their wide-ranging applications across different routes of administration, including topical, transdermal, oral, ocular, ototopical, and ungual. Additionally, the review aims to highlight their potential in the delivery of chemotherapeutic agents and to discuss recent advancements in the field, such as the development of spanethosomes, glycerospanlastics, and glucospanlastics, as reported in current literature. Method: The literature search was conducted using Web of Science, PubMed, Scopus, and the search engine Google Scholar. The results were then screened and filtered based on the relevance of titles, abstracts, and the availability of full texts. Results: Studies on spanlastics revealed that these systems have shown improved drug permeation and enhanced therapeutic efficacy across multifarious routes of delivery. These novel formulations underline the growing interest and potential of spanlastics in modern pharmaceutical research. Conclusion: Over the last decade, spanlastics have grown from a niche ocular delivery concept into a robust platform with broad delivery potential. However, their transition from lab bench to clinical use will depend on overcoming manufacturing and stability challenges and confirming efficacy through clinical trials.