Beatriz Zanchetta

Retinyl palmitate flexible polymeric nanocapsules: characterization and permeation studies.

Polymeric nanocapsules with elastic characteristics were prepared by the pre-formed polymer interfacial deposition method. The system consists of an oily core of retinyl palmitate with Span 60 and a polymeric wall of poly(D,L-lactide) (PLA). A narrow size distribution (215 nm, P.D.I. 0.10) was showed by dynamic light scattering (DLS) analyses. Particle deformability was observed by transmission electron microscopy (TEM) images and permeation of the particles through two superposed membranes of smaller pore diameters. Permeation studies were achieved using plastic surgery abdominal human skin by Franz diffusion cell. Retinyl palmitate permeates into deep skin layers. Besides, a PLA fluorescent derivative conjugated with Nile blue dye by an amide covalent bound was additionally obtained. Permeation profile of the nanocapsules with the fluorescent polymer was evaluated by confocal laser scanning microscopy (CLSM). The CLSM showed that nanocapsules were distributed uniformly, suggesting that the permeation mechanism through skin is intercellular. Thus, the use of these nanocapsules may be a feasible strategy to enhance the permeation of actives into the skin when delivery to deep layers is aimed.

Self-Emulsifying Drug Delivery Systems (SEDDS) in PharmaceuticalDevelopment

Lipid-based formulations, such as Self-Emulsifying Drug Delivery Systems (SEDDS), are an important tool for lipophilic drugs and offer the potential for enhancing drug absorption and oral bioavailability. SEDDS are a promising approach for the formulation of drug compounds with poor aqueous solubility. These systems are easily manufactured and physically stable mixtures of oil, surfactants, co-surfactants and solubilized drug substances that are administered orally in soft or hard gelatin capsules. In the gastrointestinal tract environment, these systems spontaneously emulsify. This review focuses on SEDDS formulations, describes their different types and presents case studies in which enhanced bioavailability were demonstrated in vivo using this formulation system.

Elastic liposomes containing benzophenone-3 for sun protection factor enhancement

This work was focused on the loading of benzophenone-3 in elastic liposomes composed of egg phosphatidylcholine and cholesterol, prepared by the Bangham method. Samples were characterized in terms of particle size, polydispersity index (PI), zeta potential, encapsulation efficiency and in vitro photoprotection properties. The extrusion of liposomes loading benzophenone-3 produced reduced-size (100 nm) elastic liposomes with a PI of 0.2. The active was loaded with a concentration of 20.34% (m/m) revealing changes in the ultraviolet properties after loading. On the basis of these results, it can be anticipated that liposomes are able to improve sun protector factor in vitro compared the free active.

Performance of Elastic Liposomes for Topical Treatment of Cutaneous Leishmaniasis

Non-invasive and non-toxic drugs are highly needed for the treatment of several skin diseases. Among those, local topical treatment is more desirable over oral treatment that may produce systemic side-effects. Thickening of the skin is a common feature in chronic skin diseases such as cutaneous leishmaniasis (CL). Nowadays, conventional permeation enhancers that may facilitate the drug passage through the tight stratum corneum skin barrier have been considered obsolete. Thus, appropriate delivery systems capable to carry the drug across the thickened skin are highly needed. This chapter presents an overview on the current therapy of CL and a new approach for topical treatment using conventional and pegylated liposomes as skin carrier systems for an active and highly hydrophobic antileishmanial chalcone.

L-Asparaginase Purification

L-asparaginase (L-ASNase) is the gold standard enzyme used to treat acute lymphoblastic leukemia. This disease primarily affects children; however, treatment increases survival from 20% to 90%. As a bioproduct, it is obtained via a biotechnological process and its purification usually consists of several steps that account for up to 80% of the total production costs. This review discusses available strategies for the purification of L-ASNase and highlights a process with fewer steps, and consequently, lower cost and higher yield. This process emphasizes the possibility of using a novel aqueous two-phase system extraction process to purify L-ASNase.

Poly(N-Isopropylacrylamide)-co-Acrylamide Hydrogels for the Controlled Release of Bromelain from Agroindustrial Residues of Ananas comosus.

This works reports the purification of bromelain extracted from Ananas comosus industrial residues by ethanol purification, its partial characterization from the crude extract as well as the ethanol purified enzyme, and its application onto poly(N-isopropylacrylamide)-co-acrylamide hydrogels. Bromelain was recovered within the 30-70 % ethanol fraction, which achieved a purification factor of 3.12-fold, and yielded more than 90 % of its initial activity. The resulting purified bromelain contained more than 360 U · mg(-1), with a maximum working temperature of 60 °C and pH of 8.0. Poly(N-isopropylacrylamide)-co-acrylamide hydrogels presented a swelling rate of 125 %, which was capable of loading 56 % of bromelain from the solution, and was able to release up to 91 % of the retained bromelain. Ethanol precipitation is suitable for bromelain recovery and application onto poly(N-isopropylacrylamide)-co-acrylamide hydrogels based on its processing time and the applied ethanol prices.

DESIGN AND DEVELOPMENT OF SELF-EMULSIFYING DRUG DELIVERY SYSTEMS NOVEL CARDIOACTIVE N-ACYLHYDRAZONE COMPOUND

In this study, the emphasis is placed on a strategy for enhancing the drug/carrier interaction for improved drug solubility, drug-loading capacity, self-emulsification and stability.Preliminary solubility of L294 was determined in various oils, surfactants and cosurfactants. A ternary phase diagram was constructed to identify the self-emulsifying region for the selected systems, using series concentrations of Labrafac PG, Labrasol and Transcutol HP. Self-emulsifying properties, particle size, polydispersibility, and zeta potential were studied after dilution of formulations in water.The results demonstrated the development of a self-emulsifying formulation of L294 in liquid form, which upon contact with aqueous media spontaneously forms a clear nanoemulsion having a small droplet size (around 100 nm). The zeta potential of the selected SEDDS formulation was between −11.09 and −20.50 with a viscosity around 40-60 cP. The optimum formulation consisted of a mixture of Labrafac PG, Labrasol and Transcutol HP.The L294 showed extremely low water solubility (0,006 mg.mL), and when formulated in SEDDS, its solubility increased over than 33,000 fold.This study demonstrate that SEDDS can be considered as a very good candidate to optimize the peroral administration of L294.

Studies of stability and characterization this enzyme bromelain in pineapple (Ananas comosus)

Background Bromelain is the generic name given to the set of derived endopeptidases belonging to members of the Bromeliaceae family, which belongs to the pineapple (Ananas comosus), being able to break the peptide bond, separating proteins and amino acids [1]. Bromelain possesses a wide range of therapeutic benefit as property of facilitating digestion of proteins, meat softening, ability to facilitate blood clotting [2] And economic importance related to the food industry and textiles and production of drugs resulting in an increase of its value [3]. Thus, the aim of this work is to evaluate the stability of the enzyme in relation to different temperatures and pH to make feasible the purification of the same.