Therapeutic agents such as proteins/peptides, nucleic acids and other drugs have the drawbacks of low bioavailability, rapid clearance, and high toxicity. Therefore, there is a great demand to develop delivery methods and carriers, which will bring a more efficient delivery for therapeutics.  Drug delivery systems (DDS) are more effective when it comes to increasing the bioavailability of drugs, controlling drug delivery, and maintaining the drug intact transport to the site of action while avoiding the non-diseased host tissues. 
One of these potential DDS may be phospholipids, a main component of the cellular membrane, with great biocompatibility. Research has suggested that phospholipids have been found promising for better and effective delivery of drugs. 
Phospholipids are lipids containing phosphorus, a polar potion and non-polar potion in their structures. The amphiphilicity of these molecules confers them the capacity of self-assembly, emulsifying, and wetting characteristics. These characteristics allow phospholipids to generate super-molecular structures, when in contact with an aqueous solvent, such as liposomes, ethossomes, transferosomes and phytosomes. 
Lipossomes: micro-sized spheres in which an aqueous core is surrounded by one or more lipid bilayer. The lipid bilayers are separated by water or aqueous buffer compartments. Liposomes can entrap hydrophilic or lipophilic drugs in its system and can be used as a transdermal and topical drug delivery system for many drugs for treating locally or systemic diseases. It offers many advantages as drug delivery carriers-for example they are biodegradable, non-toxic, presents cell affinity, tissue compatibility, reduces drug toxicity and improves drug stability and are able to encapsulate both water-soluble and lipophilic substances. However, conventional liposomes have some disadvantage for its permeation power on stratum corneum barrier to the skin.[1,2,3]
Transferosomes: second generation of flexible liposomes with a combination of phospholipids and a single chain surfactant that causes the destabilization of the lipid bilayer of the vesicle and increases the vesicle-elasticity or fluidity. These structures are ultra-deformable or ultra-flexible liposomes that have the property to cross the microporous barrier very efficiently, even when the available passage is much smaller than the average aggregate size. [2,3]
Ethossomes: the third generation of elastic lipid carriers. It corresponds to ethanol modified liposomes that acts as reservoir systems and offer continual delivery of medication to the desired site. Ethossomes are malleable vesicles which act with ethanol effect and lipid penetration, result in releasing of the drugs to the different layer of skin. Ethanol may also provide vesicles with soft flexible characteristics, which allow them to penetrate more easily into the deeper layers of the skin and enhance compound delivery both to deep skin strata and systemically. [2,3]
Phytosomes: formulation developed by encapsulating the plant material or plant extract within the spherical cell-like structure, which is an advanced nano-sphere or cell forms of herbal products that are better absorbed. Phytosomes produces a better pharmacokinetic and pharmacodynamic profile of drug than conventional herbal formulations. Certain water-soluble phytomolecules (mainly flavonoids and other polyphenols) can be converted into lipid-friendly complexes, by reacting herbal extract owing to their enhanced capacity to cross the lipid-rich biomembranes and finally reach the blood. It’s a novel emerging technique that is applied to phytopharmaceuticals for the enhancement of bioavailability of natural plant extract for medicinal applications. 
Nowadays, there is a recent upsurge and idea that everything that is natural is healthy. Therefore, the discovery of these drug delivery systems such as phytossomes proves to be scientific effective and also to be true to this premise. 
When it comes to all of these DDS, it might be interesting to combine them with a transdermal route for having fast and targeted delivery of the drug. There would be many health problems such as skin diseases, skin burns, migraine, allergies, cardiac problems, diabetes and trauma like a bone fracture that could easily benefit from it. 
 Jing Li, Xuling Wang, Ting Zhang, Chunling Wang, Zhenjun Huang, Xiang Luo, Yihui Deng. A review on phospholipids and their main applications in drug delivery systems. Asian Journal of Pharmaceutical Sciences. Volume 10, Issue 2. 2015. Pages 81-98. https://doi.org/10.1016/j.ajps.2014.09.004.
 K. Sudhakar, S. Jain, R. N. Charyulu. A Comparison Study of Lipossomes, Transfersomes and Ethosomes Bearing Lamivudine. International Pharmaceutical Sciences and Research. Pages 4214-2110.13040/IJPSR.0975-8232.7(10).4214-21.
 Rana, M., Kumar, A., & J. Rana, A. (2020). Drug Delivery through Targeted Approach with Special References to Phytosomes. Role of Novel Drug Delivery Vehicles in Nanobiomedicine. doi:10.5772/intechopen.86644.