Nanoemulsion (NE) of amlodipine besilate (AB) was developed by spontaneous emulsification method with the aim to enhance the solubility and oral bioavailability of AB and to achieve localized delivery of drug at target site. Pseudoternary phase diagrams were constructed to identify the NE region. The selected formulations from NE region were subjected to droplet size analysis, partitioning study and in vitro drug release. The partition coefficient was calculated and correlated with percent dissolution efficiency as a tool to predict in vitro drug release from NEs. The release of drug from NEs was significantly higher (p < 0.01) than the marketed tablet formulation. The optimal formulation contained 15% Labrafil M, 35% [Tween 80: ethanol (2:1)], and 50% by weight aqueous phase (NE3) was characterized by transmission electron microscopy (TEM) and for thermodynamic stability. The pharmacokinetics and biodistribution studies of the optimized radiolabeled formulation (99mTc-labeled) in mice (p.o.) demonstrated a relative bioavailability of 475% against AB suspension. In almost all the tested organs, the uptake of AB from NE was significantly higher (p < 0.05) than AB suspension especially in heart with a drug targeting index of 44.1%, also confirming the efficacy of nanosized formulation at therapeutic site. A three times increase in the overall residence time of NE further signifies the advantage of NEs as drug carriers for enhancing bioavailability of AB.

The objective of the present research was to develop a novel pH triggered nanoemulsified in-situ gel (NE-ISG) for ophthalmic delivery of fluconazole (FLZ) to enhance the permeation and residence time of the formulation, by overcoming the limitations associated with protective ocular barriers. Pseudoternary phase diagrams were constructed using capmul MCM (oil phase), tween 80 (surfactant) and transcutol P (cosurfactant) to identify the NE region. Nanoemulsions (NE1-NE6) of FLZ were prepared by spontaneous emulsification method and evaluated for various pharmacotechnical characteristics. NE4 was selected as optimized NE and was dispersed in carbopol 934 solution to form nanoemulsified sols (NE-ISG1 to NE-ISG5) that were expected to convert in to in-situ gels at corneal pH (7.4). The optimized NE-ISG was selected on the basis of gelation ability with a residence time up to or more than 6 h. Ex-vivo transcorneal permeation study displayed significantly higher (p < 0.05) permeation of FLZ from NE-ISG5 (337.67 µg/cm(2)) and NE4 (419.30 µg/cm(2)) than the commercial eye drops (112.92 µg/cm(2)). Hen's egg test-Chorioallantoic membrane (HET-CAM) test with zero score indicated the non-irritant property of developed NE-ISG5. Corneal toxicity study revealed no visual signs of tissue damage. Hence it can be concluded that NE-ISG5 may offer a more intensive treatment of ocular fungal infections due to higher permeation, prolonged precorneal residence time and sustained drug release along with higher in-vitro efficacy, safety and greater patient compliance.

The objective of research was to develop a novel pH-triggered polymeric nanoparticulate in situ gel (NP-ISG) for ophthalmic delivery of acetazolamide (ACZ) to enhance the conjunctival permeation and precorneal residence time of the formulation by overcoming the limitations of protective ocular barriers. Nanoparticles (NP1--NP12) were developed by nanoprecipitation method and evaluated for pharmacotechnical characteristics including transmission electron microscopy. The optimized formulation, NP10 was dispersed in carbopol 934 P to form nanoparticulate in situ gels (NP-ISG1--NP-ISG5). NP-ISG5 was selected as optimized formulation on the basis of gelation ability and residence time. Ex vivo transcorneal permeation study exhibited significantly higher ACZ permeation from NP-ISG5 (74.50 ± 2.20 mg/cm(2)) and NP10 (93.5 ± 2.25 mg/cm(2)) than eye drops (20.08 ± 3.12 mg/cm(2)) and ACZ suspension (16.03 ± 2.14). Modified Draize test with zero score indicated nonirritant property of NP-ISG5. Corneal toxicity study revealed no visual signs of tissue damage. Further, NP-ISG5 when tested for hypotensive effect on intraocular pressure (IOP) in rabbits revealed that NP-ISG5 caused significant decrease in IOP (p < 0.05) in comparison to eye drops. Conclusively, NP-ISG5 may offer intensive management of glaucoma via higher permeation, prolonged precorneal residence time and sustained drug release along with higher in vitro efficacy, safety and patient compliance.

The current research was undertaken to develop and evaluate dissolution profiles of thermodynamically stabilized sugar dispersions of the poorly water-soluble, model drug etoricoxib (ETX). Fused-sugar dispersions were formulated using sorbitol, xylitol, and maltose separately, and the binary systems were stabilized by incorporation of the antiplasticizing agents poloxamer 407 and PVP K30 to obtain ternary and quaternary systems. The sugar dispersions (F1-F12) were subjected to in vitro dissolution studies, and based on model-independent dissolution parameters, ETX-sorbitol binary/ ternary/composite systems were selected for thermodynamic stability study. The aged ETX-sorbitol composite dispersion (SF8) displayed the highest percent dissolution efficiency (%DE 80min of 78.48), the minimum t 50% of 4.45 min, and the least tendency to recrystallize (D cryst of 0.68), confirming maximum amorphization and thermodynamic stability among all the composite dispersions. The SEM photomicrographs reveal complete miscibility of drug in the aged quaternary dispersion SF8, and its diffuse reflectance (DR) spectrum confirms the absence of any chemical change. Conclusively, sorbitol binary systems can be effectively stabilized by incorporation of PVP K30-poloxamer 407 and retain the dissolution characteristics of sugar dispersions upon aging.

T he objective of the present research was to statistically optimize the sustained release of solid lipid nanoparticles (SLNs) of promethazine theoclate. The SLNs prepared by the solvent injection method were optimized by central composite design using compritol 888 ATO as lipid, poloxamer 407 as surfactant andisopropyl alcohol as solvent, and evaluated for dependent variables. The responses of the design were analyzed using Design Expert 8.0.5.2 and the analytical tools of the software were used to draw response surface plots.The design was validated by means of an extra design checkpoint formulation (F16). On account of software analysis, formulation F7 with a particle size of 266.2 ± 1.39 nm, entrapment efficiency of 89.60 ± 0.15%, cumulative release of 90.26 ± 1.18% and a desirability factor of 0.892311 was selected as the optimized formulation.It exhibited a biphasic release pattern typical of matrix release, and its release from SLNs bestfitted the Higuchi model (r 2 = 0.9949), indicating diffusion as the mechanism of drug release. Transmission electron microscopy revealed spherical nanoparticles of F7. A high recrystallization index of 76.95% indicates less chance for SLNs to undergo polymorphism and can be signified as stable formulation.