Clara Luisa Domínguez-Delgado

The Use of Sonophoresis in the Administration of Drugs Throughout the Skin

Transdermal drug delivery offers an attractive alternative to the conventional drug delivery methods of oral administration and injection. However, the stratum corneum acts as a barrier that limits the penetration of substances through the skin. Application of ultrasound to the skin increases its permeability (sonophoresis) and enables the delivery of various substances into and through the skin. Ultrasound has been used extensively for medical diagnostics and to a certain extent in medical therapy (physiotherapy, ultrasonic surgery, hyperthermia). Nevertheless, it has only recently become popular as a technique to enhance drug release from drug delivery systems. A number of studies suggest the use of ultrasound as an external mean of delivering drugs at increased rates and at desired times. This review presents the main findings in the field of sonophoresis, namely transdermal drug delivery and transdermal monitoring. Particular attention is paid to proposed enhancement mechanisms and trends in the field of topical and transdermal delivery.

Preparation and characterization of triclosan nanoparticles intended to be used for the treatment of acne

This work focuses on the preparation and characterization of nanoparticles containing triclosan. Additionally, in vitro percutaneous permeation of triclosan through pig ear skin was performed, and comparisons were made with two commercial formulations: An o/w emulsion and a solution, intended for the treatment of acne. The nanoparticle suspensions were prepared by the emulsification-diffusion by solvent displacement method, using Eudragit® E 100 as polymer. All batches showed a size smaller than 300 nm and a positive Zeta potential, high enough (20-40 mV) to ensure a good physical stability. Differential scanning calorimetry (DSC), transmission electron microscopy (TEM), and scanning electron microscopy (SEM) studies suggested that triclosan was molecularly dispersed in the nanoparticle batches containing up to 31% of triclosan, with good encapsulation efficiency (95.9%). The results of the in vitro permeation studies showed the following order for the permeability coefficients: Solution>cream≈nanoparticles; while for the amount retained in the skin, the order was as follows: cream>nanoparticles≈solution. Nanoparticles, being free of surfactants or other potentially irritant agents, can be a good option for the delivery of triclosan to the skin, representing a good alternative for the treatment of acne.

Nanocarriers for transdermal drug delivery

1Sistemas Transdermicos y Materiales Nanoestructurados, 2Toxicologia y Genetica, Universidad Nacional Autonoma de Mexico, Cuautitlan Izcalli, Mexico; 3Unidad de Ensenanza e Investigacion, Hospital Regional de Alta Especialidad de Zumpango, Zumpango, Mexico; 4Departamento de Ingenieria y Tecnologia, 5Departamento de Ciencias Quimicas, 6Laboratorio de Quimica Medicinal, Universidad Nacional Autonoma de Mexico, Cuautitlan Izcalli, Mexico; 7Departamento de Sistemas Biologicos, Universidad Autonoma Metropolitana-Xochimilco, Mexico City, Mexico

Targeting nicotine addiction: the possibility of a therapeutic vaccine

Cigarette smoking is the primary cause of lung cancer, cardiovascular diseases, reproductive disorders, and delayed wound healing all over the world. 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. The partial nicotinic receptor agonist, varenicline, has recently been approved by the US Food and Drug Administration (FDA) for smoking cessation. Clonidine and nortriptyline have demonstrated some efficacy, but side effects may limit their use to second-line treatment products. Other therapeutic drugs that are under development include rimonabant, mecamylamine, monoamine oxidase inhibitors, and dopamine D3 receptor antagonists. Nicotine vaccines are among newer products seeking approval from the FDA. Antidrug vaccines are irreversible, provide protection over years and need booster injections far beyond the critical phase of acute withdrawal symptoms. Interacting with the drug in the blood rather than with a receptor in the brain, the vaccines are free of side effects due to central interaction. For drugs like nicotine, which interacts with different types of receptors in many organs, this is a further advantage. Three anti-nicotine vaccines are today in an advanced stage of clinical evaluation. Results show that the efficiency of the vaccines is directly related to the antibody levels, a fact which will help to optimize the vaccine effect. The vaccines are expected to appear on the market between 2011 and 2012.

Chemical and Physical Enhancers for Transdermal Drug Delivery

Jose Juan Escobar-Chavez1,*, Isabel Marlen Rodriguez-Cruz2 and Clara Luisa Dominguez-Delgado2 1Unidad de Investigacion Multidisciplinaria, Laboratorio 12: Materiales Nanoestructurados y Sistemas Transdermicos, Facultad de Estudios Superiores Cuautitlan-Universidad Nacional Autonoma de Mexico, Carretera Cuautitlan–Teoloyucan, San Sebastian Xhala, Cuautitlan Izcalli, Estado de Mexico, 2Departamento de Ingenieria y Tecnologia, Seccion de Tecnologia Farmaceutica, Facultad de Estudios Superiores Cuautitlan-Universidad Nacional Autonoma de Mexico, Cuautitlan Izcalli, Estado de Mexico, Mexico

Nanocarrier Systems for Transdermal Drug Delivery

The nanomedicine which is the application of technologies on the scale of 1 to 500 nm to diagnose and treat diseases, it has become a very relevant topic nowadays. During the last century, there has been a lot of new research and patents regarding nanomedicine in health sciences [1]. The objective of nanomedicine is to diagnose and preserve the health without side effects with noninvasive treatments. To reach these goals, nanomedicine offers a lot of new tools and capabilities. The manipulation that nanomedicine provides to the drugs and other materials in the nanometer scale can change the basic properties and bioactivity of materials. The solubility, increment in surface area, control release and site-targeted delivery are some characteristics that nanotechnology can manipulate on drug delivery systems.

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. In both cases, poly(DL-lactic-co-glycolic acid) (PLGA 50:50) was used as a biodegradable polymer. Carbamazepine adsorbed onto biodegradable porous membranes shows an immediate release behavior (95% released in <15 min). Infiltration of different amounts of nanoparticles (50, 100, 400 and 600 mg of nanoparticles/0.625 g of membrane) into biodegradable porous membranes shows a Fickian diffusion according to Peppas model, and fits Higuchis model. This behavior was attributed to the diffusional barrier constituted by the nanoparticle film. As expected, the carbamazepine release rate was dependent on the amount of infiltrated/adsorbed nanoparticles into biodegradable porous membrane. DSC studies show molecular dispersion of the drug throughout the membrane.

Drug Carrier Systems Using Chitosan for Non Parenteral Routes

A safe and efficient drug carrier must offer protection to human tissues in which it is admin‐ istered as well as protection to the drugs against degradation, improve therapeutic effect, prolong biological activity, control drug release rate, and decrease the frequency of adminis‐ tration. These characteristics could be achieved by using chitosan to prepare carriers of drugs. It is almost the only cationic polysaccharide in nature with a great innate medical potential. Chitosan, a cationic polymer of natural origin, is a remarkable example of an excipient which currently has enormous potential for using in pharmaceutical dosage forms because of its properties as polyelectrolyte with reactive functional groups, gel-forming capability, high adsorption capacity, biodegradability and biocompatible and non-toxic to living tissues as well as having antibacterial, antifungal and antitumor activity. These functional properties provide suitability and extensive pharmaceutical applications such as for the preparation of drug delivery systems (drug conjugate, micro/nanoparticles, hydrogels, emulsions, biodegradable release system, etc.) and for regenerative medicine for many components such as proteins/ peptides, growth factors, anti-inflammatory drugs, antibiotics intended to be administered in non parenteral routes (oral, topical, intranasal, vaginal, rectal and ocular). Interesting appli‐ cations of chitosan has been receiving considerable attention since it has been developed systems more versatile by the incorporation of chitosan and other components in novel systems. They have provided a strategy for the functionalization by modulating physico‐

Therapeutic Applications of Sonophoresis and Sonophoretic Devices

The use of ultrasound for the delivery of drugs through the skin is commonly known as sonophoresis. The use of therapeutics and high frequencies of ultrasound for sonophoresis dates back to the 1950s, while low-frequency sonophoresis has only been investigated considerably during the past two decades. The use of ultrasound in therapeutics and drug delivery has gained significance in recent years; this is evident by the augment in patents filed and new commercial devices launched.