Chitosan-based nanoparticles for rosmarinic acid ocular delivery--In vitro tests.

In this study, chitosan nanoparticles were used to encapsulate antioxidant rosmarinic acid, Salvia officinalis (sage) and Satureja montana (savory) extracts as rosmarinic acid natural vehicles. The nanoparticles were prepared by ionic gelation using chitosan and sodium tripolyphosphate (TPP) in a mass ratio of 7:1, at pH 5.8. Particle size distribution analysis and transmission electron microscopy (TEM) confirmed the size ranging from 200 to 300 nm, while surface charge of nanoparticles ranged from 20 to 30 mV. Nanoparticles demonstrate to be safe without relevant cytotoxicity against retina pigment epithelium (ARPE-19) and human cornea cell line (HCE-T). The permeability study in HCE monolayer cell line showed an apparent permeability coefficient Papp of 3.41±0.99×10(-5) and 3.24±0.79×10(-5) cm/s for rosmarinic acid loaded chitosan nanoparticles and free in solution, respectively. In ARPE-19 monolayer cell line the Papp was 3.39±0.18×10(-5) and 3.60±0.05×10(-5) cm/s for rosmarinic acid loaded chitosan nanoparticles and free in solution, respectively. Considering the mucin interaction method, nanoparticles indicate mucoadhesive proprieties suggesting an increased retention time over the ocular mucosa after instillation. These nanoparticles may be promising drug delivery systems for ocular application in oxidative eye conditions.

Natural extracts into chitosan nanocarriers for rosmarinic acid drug delivery.

CONTEXT: Nanotechnology can be applied to deliver and protect antioxidants in order to control the oxidative stress phenomena in several chronic pathologies. Chitosan (CS) nanoparticles are biodegradable carriers that may protect antioxidants with potent biological activity such as rosmarinic acid (RA) in Salvia officinalis (sage) and Satureja montana (savory) extracts for safe and innovative therapies. OBJECTIVE: Development and characterization of CS nanoparticles as a stable and protective vehicle to deliver RA for medical applications using natural extracts as sage and savory. MATERIALS AND METHODS: Antioxidant-CS based nanoparticles were prepared by ionic gelation with sodium tripolyphosphate (TPP), at pH 5.8 with a mass ratio of 7:1 (CS:TPP), with a theoretical antioxidant-CS loading of 40-50%. The nanoparticles were then characterized by different methods such as photon correlation spectroscopy, laser Doppler anemometry, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), Fourier-transform infrared (FTIR), high-performance liquid chromatographic (HPLC), association efficiency, and antioxidant activity. RESULTS AND DISCUSSION: Individual and small sizing nanoparticles, around 300 nm, were obtained. SEM confirmed smooth and spherical nanoparticles after freeze-drying. No chemical interactions were found between antioxidants and CS, after encapsulation, by DSC and FTIR. The association efficiency was 51.2% for RA (with 40% loading) and 96.1 and 98.2% for sage and savory nanoparticles, respectively (both with 50% loading). Antioxidant activity values were higher than 0.0348 eq [Asc. Ac.] g/L/g extract and 0.4251 µmol/eq Trolox/g extract. CONCLUSION: The extracts under study are promising vehicles for RA drug delivery in CS nanocarriers.

Development and validation method for simultaneous quantification of phenolic compounds in natural extracts and nanosystems.

INTRODUCTION: Sage and savoury (Salvia sp. and Satureja montana, respectively) are plants used in traditional medicine. The quality control of their herbal formulations is of paramount concern to guarantee the expected biological activity of their anti-oxidant compounds. OBJECTIVE: To establish a simple and effective high-performance liquid chromatographic (HPLC) method to evaluate simultaneously quercetin and rosmarinic acid, in a pure form, in natural extracts (sage and savoury), and encapsulated into chitosan nanoparticles. METHODS: Chromatography was performed on an RP C18 -column, in a gradient mode with a mobile phase comprising methanol:formic acid:water 92.5:2.5:5 (v/v) at a flow rate of 0.75 mL/min and at wavelength of 280 nm. RESULTS: The method was specific, linear in the range of 0.05-1 mg/mL (R(2) = 1.00), precise at the intraday and interday levels, accurate (recovery rate 90.5 ± 0.6%), and robust to changes in equipment conditions. CONCLUSION: The method established was effective for quercetin and rosmarinic acid characterisation in natural extracts and in chitosan nanoparticles, allowing the loading capacity determination, the association efficiency as well as the in vitro release.

Cell-based in vitro models for predicting drug permeability.

INTRODUCTION: In vitro cell models have been used to predict drug permeation in early stages of drug development, since they represent an easy and reproducible method, allowing the tracking of drug absorption rate and mechanism, with an advantageous cost-benefit ratio. Such cell-based models are mainly composed of immortalized cells with an intrinsic ability to grow in a monolayer when seeded in permeable supports, maintaining their physiologic characteristics regarding epithelium cell physiology and functionality. AREAS COVERED: This review summarizes the most important intestinal, pulmonary, nasal, vaginal, rectal, ocular and skin cell-based in vitro models for predicting the permeability of drugs. Moreover, the similitude between in vitro cell models and in vivo conditions are discussed, providing evidence that each model may provisionally resemble different drug absorption route. EXPERT OPINION: Despite the widespread use of in vitro cell models for drug permeability and absorption evaluation purposes, a detailed study on the properties of these models and their in vitro-in vivo correlation compared with human data are required to further use in order to consider a future drug discovery optimization and clinical development.

Chitosan formulations as carriers for therapeutic proteins.

Protein drugs represent a significant part of the new pharmaceuticals coming on the market every year and are now widely spread in therapy to treat or relief symptomatology related to many metabolic and oncologic diseases. The delivery of therapeutic proteins is still a major drawback against their maximum pharmacodynamic due to their physicochemical properties, poor stability, permeability and biodistribution. Despite the fact that the parenteral route remains the primary route of protein administration, research continues on non-parenteral delivery routes. However, the high molecular weight of proteins, combined with their hydrophilic and charged nature, renders transport through membranes very difficult. In this regard, the biopolymer chitosan exhibits several favorable biological properties, such as biocompatibility, biodegradability, low-toxicity and mucoadhesiveness, which made it a promising candidate for the formulation of protein drugs. The success of a protein formulation depends not only on the stability of the delivery system but also on their ability to maintain the native structure and activity of the protein during preparation and the delivery, as well as during long-term storage of the formulation. Chitosan-based delivery systems have been proposed as valid approaches to provide such protective conditions. The development of novel protein delivery systems based on chitosan is a rising subject irrespective of the intended route of administration. In this review, the different approaches recently exploited to formulate and deliver therapeutic proteins are underlined.