Nanostructured lipid carriers (NLCs) are novel pharmaceutical formulations which are composed of physiological and biocompatible lipids, surfactants and co-surfactants. Over time, as a second generation lipid nanocarrier NLC has emerged as an alternative to first generation nanoparticles. This review article highlights the structure, composition, various formulation methodologies, and characterization of NLCs which are prerequisites in formulating a stable drug delivery system. NLCs hold an eminent potential in pharmaceuticals and cosmetics market because of extensive beneficial effects like skin hydration, occlusion, enhanced bioavailability, and skin targeting. This article aims to evoke an interest in the current state of art NLC by discussing their promising assistance in topical drug delivery system. The key attributes of NLC that make them a promising drug delivery system are ease of preparation, biocompatibility, the feasibility of scale up, non-toxicity, improved drug loading, and stability.

In the present study, haloperidol (HP)-loaded solid lipid nanoparticles (SLNs) were prepared to enhance the uptake of HP to brain via intranasal (i.n.) delivery. SLNs were prepared by a modified emulsification–diffusion technique and evaluated for particle size, zeta potential, drug entrapment efficiency, in vitro drug release, and stability. All parameters were found to be in an acceptable range. In vitro drug release was found to be 94.16±4.78% after 24 h and was fitted to the Higuchi model with a very high correlation coefficient (R2=0.9941). Pharmacokinetics studies were performed on albino Wistar rats and the concentration of HP in brain and blood was measured by high performance liquid chromatography. The brain/blood ratio at 0.5 h for HP-SLNs i.n., HP sol. i.n. and HP sol. i.v. was 1.61, 0.17 and 0.031, respectively, indicating direct nose-to-brain transport, bypassing the blood–brain barrier. The maximum concentration (Cmax) in brain achieved from i.n. administration of HP-SLNs (329.17±20.89 ng/mL, Tmax 2 h) was significantly higher than that achieved after i.v. (76.95±7.62 ng/mL, Tmax 1 h), and i.n. (90.13±6.28 ng/mL, Tmax 2 h) administration of HP sol. The highest drug-targeting efficiency (2362.43%) and direct transport percentage (95.77%) was found with HP-SLNs as compared to the other formulations. Higher DTE (%) and DTP (%) suggest that HP-SLNs have better brain targeting efficiency as compared to other formulations.

Surfactants are found in many existing therapeutic, cosmetic, and agro-chemical preparations. In recent years, surfactants have been employed to enhance the permeation rates of several drugs via transdermal route. The application of transdermal route to a wider range of drugs is limited due to significant barrier to penetration across the skin which is associated with the outermost stratum corneum layer. Surfactants have effects on the permeability characteristics of several biological membranes including skin. They have the potential to solubilize lipids within the stratum corneum. The penetration of the surfactant molecule into the lipid lamellae of the stratum corneum is strongly dependent on the partitioning behavior and solubility of surfactant. Surfactants ranging from hydrophobic agents such as oleic acid to hydrophilic sodium lauryl sulfate have been tested as permeation enhancer to improve drug delivery. This article reviews the status of surfactants as permeation enhancer in transdermal drug delivery of various drugs.

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A prominent research topic in contemporary advanced functional materials science is the production of smart materials based on polymers that may independently adjust their physical and/or chemical characteristics when subjected to external stimuli. Smart hydrogels based on poly(N-isopropylacrylamide) (PNIPAM) demonstrate distinct thermoresponsive features close to a lower critical solution temperature (LCST) that enhance their capability in various biomedical applications such as drug delivery, tissue engineering, and wound dressings. Nevertheless, they have intrinsic shortcomings such as poor mechanical properties, limited loading capacity of actives, and poor biodegradability. Formulation of PNIPAM with diverse functional constituents to develop hydrogel composites is an efficient scheme to overcome these defects, which can significantly help for practicable application. This review reports on the latest developments in functional PNIPAM-based smart hydrogels for various biomedical applications. The first section describes the properties of PNIPAM-based hydrogels, followed by potential applications in diverse fields. Ultimately, this review summarizes the challenges and opportunities in this emerging area of research and development concerning this fascinating polymer-based system deep-rooted in chemistry and material science.

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The topically administered drugs through conventional delivery systems have low bioavailability. Henceforth, the present study was designed to prepare and optimize clarithromycin (CTM)-loaded chitosan nanoparticles (CHNPs) to demonstrate the efficacy against microorganisms. Methods: Clarithromycin-loaded chitosan nanoparticles (CTM-CHNPs) were prepared by ionotropic gelation method. The formulation was optimized by box-Behnken design using the formulation variables like CH (A), STPP concentration (B), and stirring speed (C). Their effects were evaluated on the independent variables like particle size (Y 1) and entrapment efficiency (Y 2). Further, CTM-CHNPs were evaluated for physicochemical parameters, invitro drug release, ex-vivo permeation, bioadhesive study, corneal hydration, histopathology, HET-CAM, and antibacterial study. Results: The optimized formulation (CTM-CHNPopt) showed the low particle size (152±5 nm), which is desirable for ocular delivery. It also showed high encapsulation (70.05%), zeta potential (+35.2 mV), and was found in a spherical shape. The drug release study revealed a sustained drug release profile (82.98±3.5% in 12 hours) with Korsmeyer peppas kinetic (R 2 =0.996) release model. It showed a 2.7-fold higher corneal permeation than CTMsolution. CHNPs did not exhibit any sign of damage to excised goat cornea, which is confirmed by hydration, histopathology, and HET-CAM test. It exhibited significant (P<0.05) higher antibacterial susceptibility than CTM-solution. Conclusion: The finding of the study concluded that CTM-CHNPs can be used for effective management of bacterial conjunctivitis by increasing the precorneal residence time.

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