Development of<unk> s is one of the emerging fields of<unk>  nanotechnology (for a review on<unk>  nanotechnology, see ) with several potential applications in drug delivery, clinical medicine and research, as well as in other disciplines. Due to their unique size-dependent properties,<unk><unk> s offer the possibility to develop new therapeutics. The ability to incorporate drugs into nanocarriers offers a new prototype in drug delivery that could hold great promise for attaining the bioavailability enhancement along with controlled and site-specific drug delivery.<unk> 's are also considered to well tolerated in general, due to their composition from physiologically similar<unk> s. The conventional approaches such as use of permeation enhancers, surface modification, prodrug synthesis, complex formation and colloidal<unk>  carrier-based strategies have been developed for the delivery of drugs to intestinal lymphatics. In addition, polymeric<unk> s, self-emulsifying delivery systems, liposomes, microemulsions, micellar solutions and recently<unk> s <unk>  have been exploited as probable possibilities as carriers for oral intestinal lymphatic delivery. Drug delivery<unk> s can function as the basis for oral and parenteral drug delivery systems.<unk> s combine the advantages of<unk>  emulsion and polymeric<unk>  systems while overcoming the temporal and in vivo stability issues that troubles the conventional as well as polymeric<unk> s drug delivery approaches. It has been proposed that<unk> s combine numerous advantages over the other colloidal carriers i.e. incorporation of lipophilic and hydrophilic drugs feasible, no biotoxicity of the carrier, avoidance of organic solvents, possibility of controlled drug release and drug targeting, increased drug stability and no problems with respect to large scale production. A recent study has demonstrated the use of<unk> s as a platform for oral delivery of the nutrient mineral iron, by incorporating the hydrophilic molecule ferrous sulphate (FeSO4) in a<unk>  matrix composed of stearic acid. Carvedilol-loaded<unk> s were prepared using hot-homogenization technique for oral delivery using compritol and poloxamer 188 as a<unk>  and surfactant, respectively. Another example of drug delivery using<unk>  would be oral<unk> <unk>  suspended in distilled water, which was synthesized to trap drugs within the<unk>  structure. Upon indigestion, the<unk> s are exposed to gastric and intestinal acids that dissolve the<unk> s and release the drugs into the system. Many nano-structured systems have been employed for ocular drug delivery and yielded some promising results.<unk> s have been looked at as a potential drug carrier system since the 1990s.<unk> s do not show biotoxicity as they are prepared from physiological<unk> s.<unk> s are especially useful in ocular drug delivery as they can enhance the corneal absorption of drugs and improve the ocular bioavailability of both hydrophilic and lipophilic drugs.<unk> s have another advantage of allowing autoclave sterilization, a necessary step towards formulation of ocular preparations. Advantages of<unk> s include the use of physiological<unk> s (which decreases the danger of acute and chronic toxicity), the avoidance of organic solvents, a potential wide application spectrum (dermal, per os, intravenous) and the high pressure homogenization as an established production method. Additionally, improved bioavailability, protection of sensitive drug molecules from the outer environment water, light) and even controlled release characteristics were claimed by the incorporation of poorly water-soluble drugs in the<unk><unk>  matrix. Moreover,<unk>  can carry both lipophilic and hydrophilic drugs and are more affordable compared to polymeric/surfactant-based carriers. Nucleic acids A significant obstacle to using LNPs as a delivery vehicle for nucleic acids is that in nature,<unk> s and nucleic acids both carry a negative electric charge—meaning they do not easily mix with each other. While working at Syntex in the mid-1980s, Philip Felgner pioneered the use of artificially-created cationic<unk> s (positively-charged<unk> s) to bind<unk> s to nucleic acids in order to transfect the latter into cells. However, by the late 1990s, it was known from in vitro experiments that this use of cationic<unk> s had undesired side effects on cell membranes. During the late 1990s and 2000s, Pieter Cullis of the University of British Columbia developed ionizable cationic<unk> s which are "positively charged at an acidic pH but neutral in the blood." Cullis also led the development of a technique involving careful adjustments to pH during the process of mixing ingredients in order to create LNPs which could safely pass through the cell membranes of living organisms. As of 2021, the current understanding of LNPs formulated with such ionizable cationic<unk> s is that they enter cells through receptor-mediated endocytosis and end up inside endosomes. The acidity inside the endosomes causes LNPs' ionizable cationic<unk> s to acquire a positive charge, and this is thought to allow LNPs to escape from endosomes and release their RNA payloads. From 2005 into the early 2010s, LNPs were investigated as a drug delivery system for small interfering RNA (siRNA) drugs. In 2009, Cullis co-founded a company called Acuitas Therapeutics to commercialize his LNP research; Acuitas worked on developing LNPs for Alnylam Pharmaceuticals's siRNA drugs. In 2018, the FDA approved Alnylam's siRNA drug Onpattro (patisiran), the first drug to use LNPs as the drug delivery system. By that point in time, siRNA drug developers like Alnylam were already looking at other options for future drugs like chemical conjugate systems, but during the 2010s, the earlier research into using LNPs for siRNA became a foundation for new research into using LNPs for mRNA.<unk> s intended for short siRNA strands did not work well for much longer mRNA strands, which led to extensive research during the mid-2010s into the creation of novel ionizable cationic<unk> s appropriate for mRNA. As of late 2020, several mRNA vaccines for SARS-CoV-2 use LNPs as their drug delivery system, including both the Moderna COVID-19 vaccine and the Pfizer–BioNTech COVID-19 vaccines. Moderna uses its own proprietary ionizable cationic<unk>  called SM-102, while Pfizer and BioNTech licensed an ionizable cationic<unk>  called ALC-0315 from Acuitas. Lymphatic absorption mechanism Elucidation of intestinal lymphatic absorption mechanism from<unk> s using Caco-2 cell line as in vitro model was developed. Several researchers have shown the enhancement of oral bioavailibility of poorly water soluble drugs when encapsulated in<unk> . This enhanced bioavailibility is achieved via lymphatic delivery. To elucidate the absorption mechanism, from<unk> , human excised Caco-2 cell monolayer could be alternative tissue for development of an in-vitro model to be used as a screening tool before animal studies are undertaken. The results obtained in this model suggested that the main absorption mechanism of carvedilol loaded<unk>  could be endocytosis and, more specifically, clathrin-mediated endocytosis.
Solid lipid nanoparticle
Lipid emulsion
Polymer-protein hybrid
Immunoconjugate
Perfluorinated compound
Radioactive nanoparticle
Small molecule drug conjugate
Small modular immunopharmaceutical