Conception of nanosized hybrid liposome/poloxamer particles to thicken the interior core of liposomes and delay hydrophilic drug delivery.

Liposomes are nanocarriers composed of phospholipids, especially designed to potentially carry drugs. However, liposomes suffer in terms of leakage of small hydrophilic drugs. To control the release, a system with lipid shell and polymeric viscous core, namely Hybrid liposome/polymer inside (HLPin), has been designed. For this purpose, we setup a syringe pump apparatus equipped with homemade tubing system. HLPin formulation consisting of poloxamer (5% w/v) was found to be optimal when produced at injection rates of 5 mL.min-1. Then, we tend to characterize the HLPin with DLS, TEM, TRPS, thermal analysis and densitometry in comparison with a polymer added after formation of the liposomes. The optimal formulation was evaluated for its stability and cytotoxicity. The selected conditions and composition resulted in nanocarriers which are highly reproducible with mono-disperse size distribution with an average size of 206 ±â€¯4.8 nm and a polydispersity index of 0.15 ±â€¯0.015. Densitometry and thermal analysis results confirmed the formation of HLPin. Interestingly, HLPin were stable over 2 months, produced no cytotoxicity and exhibited slow release of rhodamine and Doxorubicin in comparison to liposome formulation. Our homemade tubing system coupled with syringe pump apparatus achieved reproducible, precisely controlled production for the HLPin formulation which can be scale up.

Advances on non-invasive physically triggered nucleic acid delivery from nanocarriers.

Nucleic acids (NAs) have been considered as promising therapeutic agents for various types of diseases. However, their clinical applications still face many limitations due to their charge, high molecular weight, instability in biological environment and low levels of transfection. To overcome these drawbacks, therapeutic NAs should be carried in a stable nanocarrier, which can be viral or non-viral vectors, and released at specific target site. Various controllable gene release strategies are currently being evaluated with interesting results. Endogenous stimuli-responsive systems, for example pH-, redox reaction-, enzymatic-triggered approaches have been widely studied based on the physiological differences between pathological and normal tissues. Meanwhile, exogenous triggered release strategies require the use of externally non-invasive physical triggering signals such as light, heat, magnetic field and ultrasound. Compared to internal triggered strategies, external triggered gene release is time and site specifically controllable through active management of outside stimuli. The signal induces changes in the stability of the delivery system or some specific reactions which lead to endosomal escape and/or gene release. In the present review, the mechanisms and examples of exogenous triggered gene release approaches are detailed. Challenges and perspectives of such gene delivery systems are also discussed.

State of the Art of Pharmaceutical Solid Forms: from Crystal Property Issues to Nanocrystals Formulation.

The solid-form screening of active principal ingredients is a challenge for pharmaceutical drug development, as more than 80 % of marketed drugs are formulated in the solid form. A broad and comprehensive study of the various solid forms of drugs is needed to enhance their translation into the clinic. Therefore, the most suitable solid form must be taken into consideration regarding ex vivo and in vivo stability, targeting, solubility, dissolution rate, and bioavailability. In this review, techniques of solid-form screening are covered, including differences in solid forms such as polymorphs, solvates, salts, co-crystals, and amorphous particles. Moreover, solid drug size reduction is also discussed, with insight into the emergence of drug nanocrystal formulations. An overview of the smallest nanocrystals reported in the literature and on the market is also provided, along with their applications and routes of administration.

Cross-Linked Polymer-Stabilized Nanocomposites for the Treatment of Bacterial Biofilms.

Infections caused by bacterial biofilms are an emerging threat to human health. Conventional antibiotic therapies are ineffective against biofilms due to poor penetration of the extracellular polymeric substance secreted by colonized bacteria coupled with the rapidly growing number of antibiotic-resistant strains. Essential oils are promising natural antimicrobial agents; however, poor solubility in biological conditions limits their applications against bacteria in both dispersed (planktonic) and biofilm settings. We report here an oil-in-water cross-linked polymeric nanocomposite (∼250 nm) incorporating carvacrol oil that penetrates and eradicates multidrug-resistant (MDR) biofilms. The therapeutic potential of these materials against challenging wound biofilm infections was demonstrated through specific killing of bacteria in a mammalian cell-biofilm coculture wound model.