Transdermal drug delivery offers an attractive alternative to the conventional drug-delivery methods of oral administration and injection. Apart from the convenience and noninvasiveness, the skin also provides a "reservoir" that sustains delivery over a period of days. It offers multiple sites to avoid local irritation and toxicity, yet it can also offer the option of concentrating drugs at local areas to avoid undesirable systemic effects. However, at present, the clinical use of transdermal delivery is limited by the fact that very few drugs can be delivered transdermally at a viable rate. This difficulty is because the stratum corneum of skin acts as an efficient barrier that limits penetration of drugs through the skin, and few noninvasive methods are known to significantly enhance the penetration of this barrier. In order to increase the range of drugs available for transdermal delivery, the use of nanocarriers has emerged as an interesting and valuable alternative for delivering lipophilic and hydrophilic drugs throughout the stratum corneum with the possibility of having a local or systemic effect for the treatment of many different diseases. These nanocarriers (nanoparticles, ethosomes, dendrimers, liposomes, etc) can be made of a lot of different materials, and they are very different in structure and chemical nature. They are too small to be detected by the immune system, and furthermore they can deliver the drug in the target organ using lower drug doses in order to reduce side effects.

Considering the increase in evidence regarding the benefits of probiotics on human health, there is interest in developing solid products with proper functional characteristics, such as temperature and pH stability, that can be added to oral solid dosage forms or to dairy products to release microorganisms directly at their site of action. The aim of this work was to develop a product with an enteric coat containing probiotics that is stable at room temperature and resists low pH to ensure that the probiotics are passed through the stomach and reach the colon. We obtained 2 enteric-release products based on the incorporation of Bifidobacterium sp. using commercial microcrystalline cellulose (BIP-Av) and prebiotic inulin (BIP-In) as cores. Both products had an initial concentration of approximately 1 × 10 8 bifidobacteria per gram (cfu/g) and showed a suitable resistance to acid; complete release from the products at a pH of 7.5 was observed at 120 min for BIP-In and 180 min for BIP-Av. The viability of bacteria in both products decreased by approximately 3 orders of magnitude. The death rate constant corresponded to 0.1143 for BIP-Av and 0.1466 for BIP-In, which means that in these storage conditions, the viability decreased slightly. Both products protected bifidobacteria for more than 2 yr, delivering a concentration of more than 1 × 10 5 cfu/g. Due to these characteristics, the products could be incorporated into solid pharmaceutical forms for oral administration. These products could have significant advantages over existing products on the market and provide protection for bacteria, allowing their passage through the stomach to reach the colon, and the viability of bacteria was maintained after storage at room temperature for more than 1 yr.

No abstract

Solid lipid nanoparticles (SLNs) have been used for carrying different therapeutic agents because they improve absorption and bioavailability. The aim of the study was to prepare lipidic nanoparticles containing cyclosporine (CyA) by the emulsification-diffusion method and to study their physicochemical stability. . Systems with Gelucire ® were characterized by particle size, Z-potential, differential scanning calorimetry (DSC), scanning electron microscopy (SEM), entrapment efficiency and in vitro release. Particle size and Z-potential were evaluated for at least three months. With a high CyA content ($60 mg) in Gelucire  SLNs, variations in size were greater and particle size also increased over time in all batches; this effect may have been caused by a probable expulsion of the drug due to the lipid's partial rearrangement. While the Z-potential decreased 10 mV after three months, this effect may be explained by the superficial properties of the drug that make the molecules to be preferably oriented at the solid-liquid interface, causing a change in the net charge of the particle. SEM confirmed size and shape of the nanoparticles. DSC studies evidenced that CyA affects the lipid structure by a mechanism still unknown. The entrapment efficiency was higher than 92%, and CyA release from SLNs was relatively fast (99.60% in 45 min).

Los superdisgregantes han despertado cierto interés en cuanto a que promueven mayor biodisponibilidad para ciertos fármacos. Los superdisgregantes son sustancias que se añaden a una formulación con el fin de romper o disgregar un comprimido en pequeñas partículas para disolver más rápido el principio activo. Esta revisión muestra una descripción general de sus mecanismos de acción, ventajas y desventajas y los superdisgregantes sintéticos más utilizados en la actualidad.