Preparation and in vitro evaluation of poly(D,L-lactide-co-glycolide) air-filled nanocapsules as a contrast agent for ultrasound imaging.

The aim of this study was to prepare air-filled nanocapsules intended ultrasound contrast agents (UCAs) with a biodegradable polymeric shell composed of poly(d,l-lactide-co-glycolide) (PLGA). Because of their size, current commercial UCAs are not capable of penetrating the irregular vasculature that feeds growing tumors. The new generation of UCAs should be designed on the nanoscale to enhance tumor detection, in addition, the polymeric shell in contrast with monomolecular stabilized UCAs improves the mechanical properties against ultrasound pressure and lack of stability.

Optimization of the emulsification and solvent displacement method for the preparation of solid lipid nanoparticles.

Objective: The essential aim of this article is to prepare solid lipid nanoparticles (SLNs) by emulsification and solvent displacement method and to determine the best process conditions to obtain submicron particles.

Methods: The emulsification and solvent displacement method is a modification of the well-known emulsification-diffusion method, but without dilution of the system. The extraction of the partially water-miscible solvent from the emulsion globules is carried out under reduced pressure, which causes the diffusion of the solvent toward the external phase, with subsequent lipid aggregation in particles whose size will depend on the process conditions.

Transdermal nortriptyline hydrocloride patch formulated within a chitosan matrix intended to be used for smoking cessation.

Objective: The aim of this study was to prepare and characterize both physically and biopharmaceutically, a nortriptyline hydrochloride (NTP-HCl) patch formulated in chitosan.

Methods: 16 g of each chitosan patch formulation (I, II and III, see Table 1 ) was poured onto rectangular glass plates (64 cm²) at a height of 1 mm and dried for 24 h at room temperature. In order to characterize the chitosan patches, polarized microscopy, in vitro skin permeation studies by passive diffusion and iontophoresis and rheological and bioadhesion studies were performed.

Development and characterization of a transdermal patch and an emulgel containing kanamycin intended to be used in the treatment of mycetoma caused by Actinomadura madurae.

Background: Mycetoma is a chronic, degenerative, and incapacitating infection of the skin and subcutaneous tissue.

Aim: This study focuses on developing a kanamycin-based auxiliary system intended to be used in the treatment of mycetoma caused by Actinomadura madurae.

Methods: Transdermal patches (with two different formulations: one with free kanamycin [K] and the other one with kanamycin adsorbed in silica [K-SG]) and an emulgel were developed.

The use of iontophoresis in the administration of nicotine and new non-nicotine drugs through the skin for smoking cessation.

Cigarette smoking is the primary cause of lung cancer, cardiovascular diseases, reproductive disorders and delayed wound healing all over the world; as such, the goals of smoking cessation are both to reduce health risks and to improve quality of life. The development of novel and more effective medications for smoking cessation is crucial in the treatment of nicotine dependence. Currently, first-line smoking cessation therapies include nicotine replacement products and bupropion.

Silica xerogels as pharmaceutical drug carriers.

This review focuses on silica xerogels obtained by the sol-gel method and their application as drug delivery systems. SiO(2) xerogels are potential biomaterials to be used as matrix materials for the extended and controlled release of different kinds of biologically active agents administered by various routes. The article includes some representative examples that describe the encapsulation of bioactive molecules and model compounds inside a silica matrix produced by the conventional sol-gel method or by ultrasound hydrolysis.

Nanoparticle infiltration to prepare solvent-free controlled drug delivery systems.

The purpose of this work was to propose a drug delivery system based on a biodegradable porous membrane, whose surface is covered by a nanoparticle film, thus achieving a controlled drug release rate. Furthermore, due to the fact that the assembly of the system is performed in aqueous medium, contact with organic solvents is avoided. The method is performed in two steps: (i) preparation of biodegradable porous membranes (by a solvent casting and particulate leaching technique) and biodegradable nanoparticles (by the emulsification-diffusion method), extensively eliminating the solvent in both of them; (ii) infiltration into membranes of an aqueous solution of a model drug (carbamazepine) and a nanoparticle dispersion.

Evaluation of SiO2 sonogels, prepared by a new catalyst-free method, as drug delivery system.

Recently, we reported on the synthesis of catalyst-free SiO(2) sonogels prepared by the sonication of a neutral distilled water/ tetraethyl ortosilicate mixture. The purpose of the present study was to evaluate the feasibility of using these sonogels as pharmaceutical delivery systems. A certified color additive (sunset yellow, SY) was used as a model compound for the release experiments.

Preparation of nanoparticles by solvent displacement using a novel recirculation system.

Submicron colloidal suspensions of poly(epsilon-caprolactone) (PCL) were prepared by the solvent displacement method, using either the conventional form or a new recirculation device. In the latter case, a process that allows the recirculation of the aqueous phase into a device, providing a continuous flow, is proposed. The influence of the organic solution injection rate and polymer concentration on mean particle size and process yield were studied for both methods.

Design and evaluation of a self-adhesive naproxen-loaded film prepared from a nanoparticle dispersion.

Naproxen-loaded nanoparticles were used to prepare, in a one-step process, unilaminar films of Eudragit E-100 (EE-100), avoiding the use of organic solvents and assuring the homogeneity and molecular dispersion of the drug. Nanoparticle films (NP-F) and conventional films (CV-F, prepared by casting of methanolic solutions onto a Teflon disc) were assayed by their mechanical properties, skin adhesivity, and calorimetric studies to compare their behavior. Different proportions of plasticizer (triacetin) were included to evaluate the quality of the films.

Chemical enhancers for the absorption of substances through the skin: Laurocapram and its derivatives.

Absorption enhancers are substances used for temporarily increasing a membrane's permeability (e.g., the skin and mucosa), either by interacting with its components (lipids or proteins) or by increasing the membrane/vehicle partition coefficient.

In vivo skin permeation of sodium naproxen formulated in pluronic F-127 gels: effect of Azone and Transcutol.

The objective of this study was to determine the penetration of sodium naproxen, formulated in Pluronic F-127 (PF-127) gels containing Azone and Transcutol as penetration enhancers, through human skin in vivo. It was found that the combination of Azone and Transcutol in PF-127 gels enhanced sodium naproxen penetration, with enhancement ratios of up to two fold compared with the formulation containing only Transcutol. These results were confirmed by TEWL and ATR-FTIR spectroscopy, suggesting a synergic action for Azone and Transcutol.

Adaptation and optimization of the emulsification-diffusion technique to prepare lipidic nanospheres.

In this study, the emulsification-diffusion method traditionally used to prepare polymeric nanoparticles was adapted to obtain lipidic nanospheres (LN) using four model lipids. The method consists of dissolving the lipid in a partially water-miscible solvent (previously saturated with water) at room temperature or at controlled temperature depending on lipid solubility. This organic phase is emulsified in an aqueous solution of a stabilizing agent (saturated with solvent) by conventional stirring at the same temperature used to dissolve the lipid.

Preparation of polymeric nanocapsules containing octyl methoxycinnamate by the emulsification-diffusion technique: penetration across the stratum corneum.

Polymeric nanocapsules (NCs) containing octyl methoxycinnamate (OMC) as lipophilic molecule were prepared, and their in vivo distribution profile through the stratum corneum (SC) was determined by the tape-stripping technique. Penetration degree of OMC formulated in NCs was compared with that obtained for a nanoemulsion (NE), and a conventional oil-in-water (o/w) emulsion (EM). To produce stable cellulose acetate phthalate (CAP) nanocapsules containing the lipophilic sunscreen, a study was conducted to optimize the process of NC preparation based on the emulsification-diffusion technique.

Effects of sucrose oleate and sucrose laureate on in vivo human stratum corneum permeability.

Purpose: The purpose of this work was to 1) investigate the effect of sucrose esters (sucrose oleate and sucrose laureate in water or in Transcutol, TC) on the stratum corneum (SC) barrier properties in vivo and 2) examine the impact of these surfactant-like molecules on the in vivo percutaneous penetration of a model penetrant 4-hydroxybenzonitrile (4-HB).

Methods: Attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy and transepidermal water loss measurements were used to evaluate the sucrose oleate- and sucrose laureate-induced biophysical changes in SC barrier function in vivo. In addition.