Néstor Mendoza-Muñoz

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. The critical variables affecting the process, such as stirring rate, the proportion of phases in the emulsion, and the amount of stabilizer and lipid, were evaluated and optimized. Results: By this method, it was possible to obtain a high yield of solids in the dispersion for the lipids evaluated (Compritol® ATO 888, Geleol®, Gelucire® 44/14, and stearic acid). SLNs of up to ∼20 mg/mL were obtained for all lipids evaluated. A marked reduction in size, between 500 and 2500 rpm, was seen, and a transition from micro- to nanometric size was observed. The smaller particle sizes obtained were 113 nm for Compritol® ATO 888, 70 nm for Gelucire® 44/14, 210 nm for Geleol®, and 527 nm for stearic acid, using a rotor–stator homogenizer (Ultra-Turrax®) at 16,000 rpm. The best phase ratio (organic/aqueous) was 1 : 2. Conclusions: The process proposed in this study is a new alternative to prepare SLNs with technological potential.

The Impact of the Salting-Out Technique on the Preparation of Colloidal Particulate Systems for Pharmaceutical Applications

The recent advances in nanotechnology and its application in medicine have merged into a new concept called nanomedicine. Colloidal drug delivery systems and specifically polymeric nanoparticles are one of the most promising novel drug carriers due to their capacity for passive or active targeting for therapeutic and diagnostic applications. The introduction of novel therapeutic nanoscaled agents requires simple, efficient and feasible industrial-scale production methods. Biodegradable polymeric nanoparticles are usually prepared from preformed polymers by five techniques: emulsification- solvent evaporation, solvent displacement, salting-out, emulsification-solvent diffusion and double emulsion solvent evaporation. This review discusses the use of the salting-out technique for the preparation of nanoparticles in the development of systems for drug delivery and other pharmaceutical applications. The relevant applications, formulations and release characteristics of novel colloidal drug delivery preparations from research literature and patents are summarized. This review is intended as a tool for the rational development of polymeric colloidal systems for pharmaceutical use.

Nanosystems in Edible Coatings: A Novel Strategy for Food Preservation

Currently, nanotechnology represents an important tool and an efficient option for extending the shelf life of foods. Reducing particle size to nanometric scale gives materials distinct and improved properties compared to larger systems. For food applications, this technology allows the incorporation of hydrophilic and lipophilic substances with antimicrobial and antioxidant properties that can be released during storage periods to increase the shelf life of diverse products, including whole and fresh-cut fruits and vegetables, nuts, seeds, and cheese, among others. Edible coatings are usually prepared with natural polymers that are non-toxic, economical, and readily available. Nanosystems, in contrast, may also be prepared with biodegradable synthetic polymers, and liquid and solid lipids at room temperature. In this review, recent developments in the use of such nanosystems as nanoparticles, nanotubes, nanocomposites, and nanoemulsions, are discussed critically. The use of polymers as the support matrix for nanodispersions to form edible coatings for food preservation is also analyzed, but the central purpose of the article is to describe available information on nanosystems and their use in different food substrates to help formulators in their work.

The emulsification-diffusion method to obtain polymeric nanoparticles: Two decades of research

Abstract Nowadays, several methods for preparing submicron particles from polymers are available. The emulsification-diffusion (E-D) method was proposed as an alternative to avoid the toxicity-solvent problems caused by the emulsification-evaporation; additionally, its simple implementation, high reproducibility and versatility have been confirmed for different research groups. This method is one of the first techniques analyzed from a mechanistic point of view and it has been used to encapsulate several kinds of drugs, including peptides and proteins. The objectives of this chapter are focused on the study of the pharmaceutical impact of the emulsification- diffusion method since it was introduced. We review and describe the critical preparative variables, constitutive materials, formation mechanisms and performance of the E-D method. The second part of the chapter includes an extensive collection of different types of drug-loaded nanoparticles obtained by this method. Finally, some novel innovations and applications of the method have also been compiled.

Controlled-release biodegradable nanoparticles: From preparation to vaginal applications

Abstract This study aimed to prepare poly (d,l‐lactide‐co‐glycolide) (PLGA) nanoparticles (NPs) with chitosan (CTS) surface modification to be used as a vaginal delivery system for antimycotic drugs. Clotrimazole was encapsulated with entrapment efficiencies of 86.1 and 68.9% into Clotrimazole‐PLGA‐NPs (CLT‐PLGA‐NPs) and PLGA‐NPs with CTS‐modified surface (CLT‐PLGA‐CTS‐NPs), respectively. The later NPs exhibited a larger size and higher positive zeta potential (Z potential) in comparison to unmodified NPs. In vitro release kinetic studies indicated that Clotrimazole was released in percentages of > 98% from both nanoparticulate systems after 18 days. Antifungal activity and mucoadhesive properties of NPs were enhanced when CTS was added onto the surface. In summary, these results suggested that Clotrimazole loaded into PLGA‐CTS‐NPs has great potential for vaginal applications in treating vaginal infections generated by Candida albicans. Graphical abstract Figure. No caption available.

Feasibility of obtaining in situ nanocapsules through modified self-microemulsifying drug delivery systems. A new manufacturing approach for oral route administration

Abstract Nanocapsules (NCs) are submicron-sized core shell systems which present important advantages such as improvement of drug efficacy and bioavailability, prevention of drug degradation, and provision of controlled-release delivery. The available methods for NC production require expensive recovery and purification steps which compromised the morphology of NCs. Industrial applications of NCs have been avoided due to the aforementioned issues. In this study, we developed a new method based on a modified self-microemulsifying drug delivery system (SMEDDS) for in situ NCs production within the gastrointestinal tract. This new methodology does not require purification and recovery steps and can preserve the morphology and the functionality of NCs. The in situ formed NCs of Eudragit® RL PO were compared with nanospheres (NEs) in order to obtain evidence of their core-shell structure. NCs presented a spherical morphology with a size of 126.2 ± 13.1 nm, an ibuprofen encapsulation efficiency of 31.3% and a zeta-potential of 37.4 mV. Additionally, NC density and release profile (zero order) showed physical evidence of the feasibility of NCs in situ creation.

Nanoparticles as Dental Drug-Delivery Systems

Nanotechnology has become one of the most important and exciting disciplines over the past decade. This chapter is to provide an overview of nanoparticles and their applications as dental drug-delivery systems. Nanoparticles (nanospheres and nanocapsules) are solid nanoscale particles formed from biocompatible materials containing an active substance produced by mechanical or chemical methods. Some of the most important applications of these drug-delivery systems in different dental pathologies and their potential to solve other dental challenges are analyzed, e.g., caries control and restoration, tooth remineralization, oral biofilm and periodontal disease management, and root canal disinfection.

Comprehensive mapping of human body skin hydration: A pilot study

Previous studies analyzed a series of representative anatomical regions in the human body; however, there is a wide structural and cellular variability in the constitution of the skin. Our objective was to perform a comprehensive assessment of human skin hydration throughout the largest possible area.

Approaches in Polymeric Nanoparticles for Vaginal Drug Delivery: A Review of the State of the Art

The vagina is a region of administration with a high contact surface to obtain local or systemic effects. This anatomical area represents special interest for government health systems for different sexually transmitted infections. However, the chemical changes of the vagina, as well as its abundant mucus in continuous exchange, act as a barrier and a challenge for the development of new drugs. For these purposes, the development of new pharmaceutical forms based on nanoparticles has been shown to offer various advantages, such as bioadhesion, easy penetration of the mucosa, and controlled release, in addition to decreasing the adverse effects of conventional pharmaceutical forms. In order to obtain nanoparticles for vaginal administration, the use of polymers of natural and synthetic origin including biodegradable and non-biodegradable systems have gained great interest both in nanospheres and in nanocapsules. The main aim of this review is to provide an overview of the development of nanotechnology for vaginal drug release, analyzing the different compositions of polymeric nanoparticles, and emphasizing new trends in each of the sections presented. At the end of this review, a section analyzes the properties of the vehicles employed for the administration of nanoparticles and discusses how to take advantage of the properties that they offer. This review aims to be a reference guide for new formulators interested in the vaginal route.

Nanotechnology As Potential Tool for siRNA Delivery in Parkinson's Disease

BACKGROUND The lack of an outright treatment for Parkinsons disease (PD) is a pivotal concern in medicine and has driven the search for novel alternatives for treating the disease. Among the proposed approaches, small interfering RNA (siRNA)-based therapy is attracting significant attention as a potential method for the treatment of PD; however, siRNAs delivery possesses potential drawbacks, such as reduced stability in blood circulation and low capacity for reaching the target site. OBJECTIVE This review aims to explore siRNA-based approaches to PD and the latest advances for designing nanoparticles that effectively target siRNAs to the action site and that protect these against degradation in blood circulation. RESULTS siRNA-based approaches provide an interesting option for designing new strategies for treating PD through the silencing of genes, whose abnormal expressions contribute to the pathophysiology of the disease; however, siRNA delivery to the brain is a key issue that remains unsolved to date. Current research efforts are focused on designing vectors that effectively transport and protect siRNAs. In this regard, nanoparticles are being developed as carriers for siRNAs with controlled delivery efficiency and low toxicity profiles, and these represent an alternative to common vectors. CONCLUSION Identification of putative gene targets for siRNA therapy of PD has set the pace for researching non-viral vectors; however, the technological aspects for tackling the challenge that siRNAs targeting to the brain represents are essentials. In this respect, the formulation of siRNAs in nanoparticles would avoid harmful side effects, such as immunogenic and oncogenic drawbacks.