The most widely used methods for transdermal administration of the drugs are hypodermic needles, topical creams, and transdermal patches. The effect of most of the therapeutic agents is limited due to the stratum corneum layer of the skin, which serves as a barrier for the molecules and thus only a few molecules are able to reach the site of action. A new form of delivery system called the microneedles helps to enhance the delivery of the drug through this route and overcoming the various problems associated with the conventional formulations. The primary principle involves disruption of the skin layer, thus creating micron size pathways that lead the drug directly to the epidermis or upper dermis region from where the drug can directly go into the systemic circulation without facing the barrier. This review describes the various potential and applications of the microneedles. The various types of microneedles can be fabricated like solid, dissolving, hydrogel, coated and hollow microneedles. Fabrication method selected depends on the type and material of the microneedle. This system has increased its application to many fields like oligonucleotide delivery, vaccine delivery, insulin delivery, and even in cosmetics. In recent years, many microneedle products are coming into the market. Although a lot of research needs to be done to overcome the various challenges before the microneedles can successfully launch into the market.

Ocular diseases have a significant effect on vision and quality of life.

Nanocarriers have the utmost significance for advancements in drug delivery and nanomedicine technology. They are classified as polymer-based nanocarriers, lipid-based nanocarriers, viral nanoparticles, or inorganic nanoparticles, depending on their constituent parts. Lipid-based nanocarrier systems have gained tremendous attention over the years because of their noteworthy properties like high drug-loading capacity, lower toxicity, better bioavailability and biocompatibility, stability in the gastrointestinal tract, controlled release, simpler scale-up, and validation process. Nanocarriers still have some disadvantages like poor drug penetration, limited drug encapsulation, and poor targeting. These disadvantages can be overcome by their surface modification. Surface-modified nanocarriers result in controlled release, enhanced penetration efficiency, and targeted medication delivery. In this review, the authors summarize the numerous lipid-based nanocarriers and their functionalization through various surface modifiers such as polymers, ligands, surfactants, and fatty acids. Recent examples of newly developing surface-modified lipid-based nanocarrier systems from the available literature, along with their applications, have been compiled in this work.

Nano-emulgel is an emerging drug delivery system intended to enhance the therapeutic profile of lipophilic drugs. Lipophilic formulations have a variety of limitations, which includes poor solubility, unpredictable absorption, and low oral bioavailability. Nano-emulgel, an amalgamated preparation of different systems aims to deal with these limitations. The novel system prepared by the incorporation of nano-emulsion into gel improves stability and enables drug delivery for both immediate and controlled release. The focus on nano-emulgel has also increased due to its ability to achieve targeted delivery, ease of application, absence of gastrointestinal degradation or the first pass metabolism, and safety profile. This review focuses on the formulation components of nano-emulgel for topical drug delivery, pharmacokinetics and safety profiles.