Due to complicated anatomical and physical properties, targeted drug delivery to ocular tissues continues to be a key challenge for formulation scientists. Various attempts are currently being made to improve the in vivo performance of therapeutic molecules by encapsulating them in various nanocarrier systems or devices and administering them via invasive/non-invasive or minimally invasive drug administration methods. Biocompatible and biodegradable lipid nanoparticles have emerged as a potential alternative to conventional ocular drug delivery systems to overcome various ocular barriers. Lipid-based nanocarrier systems led to major technological advancements and therapeutic advantages during the last few decades of ocular therapy, such as high precorneal residence time, sustained drug release profile, minimum dosing frequency, decreased drug toxicity, targeted site delivery, and, therefore, an improvement in ocular bioavailability. In addition, such formulations can be given as fine dispersion in patient-friendly droppable preparation without causing blurred vision and ocular sensitivity reactions. The unique advantages of lipid nanoparticles, namely, solid lipid nanoparticles, nanostructured lipid carriers, nanoemulsions, and liposomes in intraocular targeted administration of various therapeutic drugs are extensively discussed. Ongoing and completed clinical trials of various liposome-based formulations and various characterization techniques designed for nanoemulsion in ocular delivery are tabulated. This review also describes diverse solid lipid nanoparticle preparation methods, procedures, advantages, and limitations. Functionalization approaches to overcome the drawbacks of lipid nanoparticles, as well as the exploration of new functional additives with the potential to improve the penetration of macromolecular pharmaceuticals, would quickly progress the challenging field of ocular drug delivery systems.

To investigate mechanisms by which thymoquinone (TQ) can prevent methotrexate‐ (MTX‐) induced hepatorenal toxicity, TQ (10 mg/kg) was administered orally for 10 days. In independent rat groups, MTX hepatorenal toxicity was induced via 20 mg/kg i.p. at the end of day 3 of experiment, with or without TQ. MTX caused deterioration in kidney and liver function, namely, blood urea nitrogen, creatinine, alanine aminotransferase, and aspartate aminotransferase. MTX also caused distortion in renal and hepatic histology, with significant oxidative stress, manifested by decrease in reduced glutathione and catalase, as well as increase in malondialdehyde levels. In addition, MTX caused nitrosative stress manifested by increased nitric oxide, with upregulation of inducible nitric oxide synthase. Furthermore, MTX caused hepatorenal inflammatory effects as shown by increased tumor necrosis factor‐α, besides upregulation of necrosis factor‐κB and cyclooxygenase‐2 expressions. MTX also caused apoptotic effect, as it upregulated caspase 3 in liver and kidney. Using TQ concurrently with MTX restored kidney and liver functions, as well as their normal histology. TQ also reversed oxidative and nitrosative stress, as well as inflammatory and apoptotic signs caused by MTX alone. Thus, TQ may be beneficial adjuvant that confers hepatorenal protection to MTX toxicity via antioxidant, antinitrosative, anti‐inflammatory, and antiapoptotic mechanisms.

Nanoemulsion is one of the potential drug delivery strategies used in topical ocular therapy. The purpose of this study was to design and optimize a nanoemulsion-based system to improve therapeutic efficacy of moxifloxacin in ophthalmic delivery. Moxifloxacin nanoemulsions were prepared by testing their solubility in oil, surfactants, and cosurfactants. A pseudoternary phase diagram was constructed by titration technique and nanoemulsions were obtained with four component mixtures of Tween 80, Soluphor^® P, ethyl oleate and water. An experiment with simplex lattice design was conducted to assess the influence of formulation parameters in seven nanoemulsion formulations (MM1–MM7) containing moxifloxacin. Physicochemical characteristics and in vitro release of MM1–MM7 were examined and optimized formulation (MM3) was further evaluated for ex vivo permeation, antimicrobial activity, ocular irritation and stability. Drug pharmacokinetics in rabbit aqueous humor was assessed for MM3 and compared with conventional commercial eye drop formulation (control). MM3 exhibited complete drug release in 3 h by Higuchi diffusion controlled mechanism. Corneal steady state flux of MM3 (~32.01 µg/cm²/h) and control (~31.53 µg/cm²/h) were comparable. Ocular irritation study indicated good tolerance of MM3 and its safety for ophthalmic use. No significant changes were observed in the physicochemical properties of MM3 when stored in the refrigerator for 3 months. The greater aqueous humor concentration (C_max; 555.73 ± 133.34 ng/mL) and delayed T_max value (2 h) observed in MM3 suggest a reduced dosing frequency and increased therapeutic efficacy relative to control. The area under the aqueous humor concentration versus time curve (AUC_{0–8 h}) of MM3 (1859.76 ± 424.51 ng·h/mL) was ~2 fold higher (p < 0.0005) than the control, suggesting a significant improvement in aqueous humor bioavailability. Our findings suggest that optimized nanoemulsion (MM3) enhanced the therapeutic effect of moxifloxacin and can therefore be used as a safe and effective delivery vehicle for ophthalmic therapy.

Curcumin, an organic phenolic molecule that is extracted from the rhizomes of Curcuma longa Linn, has undergone extensive evaluation for its diverse biological activities in both animals and humans. Despite its favorable characteristics, curcumin encounters various formulation challenges and stability issues that can be effectively addressed through the application of nanotechnology. Nano-based techniques specifically focused on enhancing solubility, bioavailability, and therapeutic efficacy while mitigating toxicity, have been explored for curcumin. This review systematically presents information on the improvement of curcumin’s beneficial properties when incorporated, either individually or in conjunction with other drugs, into diverse nanosystems such as liposomes, nanoemulsions, polymeric micelles, dendrimers, polymeric nanoparticles, solid-lipid nanoparticles, and nanostructured lipid carriers. Additionally, the review examines ongoing clinical trials and recently granted patents, offering a thorough overview of the dynamic landscape in curcumin delivery. Researchers are currently exploring nanocarriers with crucial features such as surface modification, substantial loading capacity, biodegradability, compatibility, and autonomous targeting specificity and selectivity. Nevertheless, the utilization of nanocarriers for curcumin delivery is still in its initial phases, with regulatory approval pending and persistent safety concerns surrounding their use.