Technical Considerations, Applications, and Benefits of Organogels in Topical Drug Delivery Systems.

Organogels represent semi-solid systems where an organic liquid phase is entrapped within a three-dimensional network formed by self-assembled, crosslinked, or entangled gelator fibers. These versatile materials find applications in a wide range of fields, including chemistry, pharmaceuticals, cosmetics, biotechnology, and food technology. Notably, in pharmacology, they serve as valuable platforms for drug and vaccine delivery, facilitating the transport of active ingredients through various routes such as transdermal, oral, and parenteral. However, their previous utility as drug delivery systems was hindered by the toxicity associated with the organic solvents used. The pharmacokinetics of medications delivered via organogels are primarily influenced by the distinctive properties of these materials, specifically their "high permeability and poor aqueous solubility," which can impact the bioavailability of the drugs. Organogels can be employed topically or for the controlled release of medications through cutaneous administration and percutaneous absorption, expanding their scope of application beyond conventional drug delivery methods. Organogels hold significant promise as drug delivery vehicles due to their biocompatibility, non-irritating properties, and thermoremanent characteristics. They enable the formulation of diverse drug delivery systems by incorporating both hydrophilic and hydrophobic bioactive compounds within the gel matrix. This comprehensive review offers an overview of organogels, encompassing their nature, synthesis, characterization, and properties. Special attention is directed towards cutting-edge technologies employed in designing organogels as potential controlled delivery systems, with a focus on their emerging therapeutic applications.

PAU Smart Seeder: a novel way forward for rice residue management in North-west India.

In winter, the paddy residues become wet during morning and late evening due to dew, which restricts the operation of sowing machines (Happy Seeder and Super Seeder) into paddy residues, as wet residues do not slide on furrow openers/tines. A PAU Smart Seeder (PSS) was developed and evaluated for a four-wheel tractor that can sow wheat with optimum crop establishment in combined harvested rice fields. The PSS were evaluated for its performance under varying straw load, forward speed, and rotor speed in terms of fuel consumption, field capacity, seed emergence, and grain yield. The crop establishment and wheat yield of PSS was also compared with the existing straw management machines Happy Seeder (HS) and Super Seeder (SS) under heavy paddy residue conditions. The effect of the straw load was more pronounced on dependent variables than the effect of the speed index. PSS performance was best at a forward speed of 2.6 km h-1, rotor speed of 127.5 rpm, and a straw load of 6 t ha-1. Average fuel consumption using PSS was lower than SS but higher than HS. Wheat emergence was higher by 15.6 and 25.7% on the PSS plots compared to HS and SS, respectively. Average wheat grain yield in PSS plots was significantly higher by 12.7 and 18.9% than SS and HS, respectively in one experiment, while the grain yield was similar for both PSS and HS in other experiments. PSS has a novel mechanism to manage paddy straw and simultaneously sow wheat into a heavy straw load (> 8 t ha-1) mixture of anchored and loose straw. In conclusion, PSS showed promise for in-situ management of rice straw as it eliminates most of the operational problems encountered by the existing seeders (HS and SS).

Comparative evaluation of modified crater (endonucleation) chop and conventional crater chop techniques during phacoemulsification of hard nuclear cataracts: A randomized study.

PURPOSE: To compare the clinical outcomes of endonucleation chop (EC) versus conventional crater (CC) chop techniques in phacoemulsification of hard nuclear cataracts. METHODS: In this Prospective, longitudinal, randomized controlled study with double-blinding. Hundred consecutive eyes with uncomplicated cataracts (nucleus grades 3 and 4) were equally divided into Group A (EC) and Group B (CC). Intraoperative effective phacoemulsification time (EPT) and balanced salt solution (BSS) volume used was noted. Postoperative central corneal thickness (CCT), endothelial cell density (ECD), uncorrected Visual Acuity (UCVA), best-corrected visual acuity (BCVA), and IOP were recorded at days 1, 7, 30, and 90 postoperatively. The Chi-square test (categorical data), Mann-Whitney U test, and t-tests for other parameters were done. RESULTS: The mean EPT in Groups A and B were 6.6 and 14.25 s, respectively (P < 0.001). The BSS volume used was 105.9 and 221.7 mL, respectively (P < 0.001). At 3 months, the ECD loss was 4.35 and 8.6%, respectively (P = 0.025). The-first day CCT was significantly increased in Group B but was the same in both groups at 3 months. A significant improvement in BCVA was noted in both groups. This new technique significantly reduces EPT, the BSS used, and ECD loss. CONCLUSION: Compared with the CC chop technique, the EC technique for phacoemulsification of hard nuclear cataracts conserved phacoemulsification energy and minimized exposure to the intraocular irrigating solution, provided a significant reduction in corneal endothelial damage, and led to faster visual rehabilitation.

Surface-induced morphology and free-energy pathways in breakup of a nematic liquid crystalline cylinder.

We compute the surface-induced morphology and the free-energy pathways as a cylindrical liquid crystalline filament with preferred homeotropic (orthogonal) interface orientation passes through a sequence of growing sinusoidal perturbations and breaks up into droplets. Liquid crystalline morphology is determined using a simulated annealing algorithm [R. K. Goyal and M. M. Denn, Phys. Rev. E, 75, 021704 (2007)] to minimize the Oseen-Frank free energy. A first-order morphological transition with a finite energy barrier is required when the perturbation amplitude exceeds a critical value, and it is possible that progress towards breakup will be kinetically trapped in a varicose cylindrical shape. This result may be related to the apparent kinetic trapping of dispersed nematic 4'-octyl-4-biphenylcarbonitrile in a gel state reported by Inn and Denn [J. Rheol., 49, 887 (2005)].

Orientational multiplicity and transitions in liquid crystalline droplets.

Orientation distributions in droplets of liquid crystals with homeotropic anchoring are computed with a simulated annealing algorithm that minimizes the free energy of the Oseen-Frank continuum theory. The droplets exhibit multiple orientational steady states that are separated by finite energy barriers over the entire range of the dimensionless ratio of surface to elastic forces, with maximum transition energy densities of the order of 2000 J/m3 (Pa) for a typical liquid crystalline droplet with a spherical radius of 1 microm. The transition energy densities decrease with elongation to spheroidal droplets with aspect ratios of four or more, indicating that droplet elongation is favored to drive surface-induced transitions.

Power-law and exponential segregation in two-dimensional silos of granular mixtures.

When a binary mixture of granular materials, differing in shape or size, is poured into a quasi-two-dimensional silo, segregation of the mixture is observed. Depending on the size ratio d2/d1 of the species, the mixture segregates completely or partially into the pure species. To study the partial-segregation effect we propose a theoretical model based on the work of Boutreux and de Gennes [J. Phys. I 6, 1295 (1996)] but we introduce more realistic collision functions. To compare the partial- and complete-segregation effects, we also discuss calculations for the complete-segregation model proposed by Makse [Phys. Rev. E 56, 7008 (1997)]. Our experiments confirm the analytical solutions for both types of segregation. We find that the transition from complete segregation to partial segregation appears as the size ratio of the species is decreased below a critical value, which is found to be d2/d1 approximately 1.4 for our system. Our experimental and analytical studies predict the regime for applicability of both partial- and complete-segregation models in terms of the size ratio of the species and the respective model parameters.