In this research article, we focused on lipid-based supramolecular assembly 'nanocochleates' composed of negatively charged phospholipids and divalent cation as drug carrier for systemic delivery system and discussed their formulations, optimisation, characterization, in vitro and in vivo performance.

Background. Oxybenzone, a broad spectrum sunscreen agent widely used in the form of lotion and cream, has been reported to cause skin irritation, dermatitis, and systemic absorption. Aim. The objective of the present study was to formulate oxybenzone loaded microsponge gel for enhanced sun protection factor with reduced toxicity. Material and Method. Microsponge for topical delivery of oxybenzone was successfully prepared by quasiemulsion solvent diffusion method. The effects of ethyl cellulose and dichloromethane were optimized by the 32 factorial design. The optimized microsponges were dispersed into the hydrogel and further evaluated. Results. The microsponges were spherical with pore size in the range of 0.10–0.22 µm. The optimized formulation possesses the particle size and entrapment efficiency of 72 ± 0.77 µm and 96.9 ± 0.52%, respectively. The microsponge gel showed the controlled release and was nonirritant to the rat skin. In creep recovery test it had shown highest recovery indicating elasticity. The controlled release of oxybenzone from microsponge and barrier effect of gel result in prolonged retention of oxybenzone with reduced permeation activity. Conclusion. Evaluation study revealed remarkable and enhanced topical retention of oxybenzone for prolonged period of time. It also showed the enhanced sun protection factor compared to the marketed preparation with reduced irritation and toxicity.

Cochleates, a type of lipid based drug delivery system, are solid particulates made up of large continuous lipid bilayer sheets rolled up in a spiral structure with little or no internal aqueous phase. These nano-sized or sub-micron sized structures are generated on fusion of negatively charged liposomes with metal cations. They are efficient in encapsulating drug molecules that are hydrophobic and hydrophilic; positively charged as well as negatively charged. The interior of a cochleate structure remains substantially intact irrespective of outer harsh environmental conditions or enzymes. Cochleate technology is applicable for administration through parenteral, topical as well as oral routes and can be formulated in liquid or powder form. Cochleates have been reported to improve the oral bioavailability; improve the safety of the drugs by decreasing side effects and increasing drug efficacy; all of which lead to enhanced patient compliance. This review article highlights the important aspects of cochleates such as their structure, properties, methods of preparation, stability, advantages, applications and current status. The information provided herein should help formulators in judiciously selecting cochleate technology for delivery of drugs.

Andrographolide, a major bioactive phytoconstituent derived from Androgaphis paniculata that is safe and beneficial in several ailments, was formulated into pH-sensitive nanoparticle suspension with a view of improving its oral bioavailability. The andrographolide-loaded pH-sensitive nanoparticles were prepared by nanoprecipitation technique using Eudragit® EPO (cationic poly methacrylate copolymer). The 3(2) factorial design was used to optimize the amount of polymer and stabilizer (Pluronic® F-68). The optimized batch obtained using 0.45% w/v of Eudragit® EPO and 0.6% w/v of Pluronic® F-68 showed high-encapsulation efficiency of 93.8±0.67% with particle size of 255±9 nm and zeta potential of 29.3±3.4 mV. The bioavailability of andrographolide from optimized nanoparticles and pure andrographolide was assessed in male Wistar albino rats at a dose of 10 mg/kg. As compared to the pure andrographolide, almost 2.2 and 3.2-fold increase in AUC0-∞, Cmax and 121.53% increase in relative bioavailability were observed for andrographolide from pH-sensitive nanoparticles (P<0.05). Shorter Tmax by about fourfold difference were observed with 2.2-fold decrease in Cl/F. The improved dissolution rate owing to its reduced particle size, increased surface area and reduced diffusion layer thickness may have contributed to oral bioavailability. The results clearly indicate the potential of pH-sensitive nanoparticles for oral delivery of low-bioavailability phytoconstituents such as andrographolide.