This study depicts coenzyme Q10 (CoQ10) and retinaldehyde (RAL) co-loaded nanostructured lipid carriers (NLCs); having activity on different targets of photoageing, which can overcome deficits of conventional topical dosage forms. The developed NLCs were characterised for particle size, polydispersity index and percent entrapment efficiency (%EE), followed by their incorporation into Carbopol® 934 P-NF gel. In vitro cellular uptake and cytotoxicity assay was performed to evaluate NLCs and in vivo study on ultraviolet- (UV) induced wrinkle model to determine efficacy of NLCs. The developed stable, homogenous and spherical NLCs with size range of 200-230 nm and more than 80 %EE, showed prolonged, biphasic in vitro release pattern for CoQ10 and RAL. Ex vivo study portrayed negligible permeation through skin but appreciable penetration and distribution in skin layers. This has shown good uptake of both drugs with least cytotoxicity in cell culture studies. In vivo irritation study on Sprague Dawley (SD) rats and pharmacodynamic study on female Swiss albino mice proved it less irritant and efficacious. The developed NLCs thus hold promise in the efficient management of wrinkle and their reduction as indicated by the data obtained.

Dexamethasone (Dex) is one of the most commonly used anti-vascular endothelial growth factor (anti-VEGF) drug being used in ocular diseases whether it is associated with anterior segment or posterior segment. For diseases of posterior segment of eye, Dex is delivered as intravitreal implant but the route used for the same is very invasive and poses several hazards on long term use. Thus, topical formulation with ability to outreach retina from ocular surface was intended. Thus, polyethyleneglycolylated (PEGylated) microemulsion (ME) was attempted as it can cross the membranous barrier of eye (cornea, conjunctiva, and sclera) and remain afloat in fluidic barrier (aqueous humor, choroid etc) as well. Present investigation involved development of Dex loaded PEGylated ME which was stable, non-toxic to ocular surface, capable to cross cornea and enhanced residence as well as availability of loaded drug in retina. The developed PEGylated ME had physicochemical properties like size (15.98 ± 3.05 nm), polydispersity index (0.25 ± 0.04), zeta potential (-0.04 ± 0.47 mV), % transmittance (99.84 ± 1.17 %), and drug content (99.32 ± 3.21 %). It showed sustained Dex release in in vitro conditions. It also displayed efficiency in enhancing retention of drug in retina in in vivo pharmacokinetic study on Sprague dawley rats. PEGylated ME can retain the drug in retina of rats longer than simple eye drop solution via topical ocular route.