A comparative study of stabilising effect and antioxidant activity of different antioxidants on levodopa-loaded liposomes.

The aim of this study was to evaluate the stability of levodopa liposomes co-loaded with three different antioxidants (curcumin, ascorbic acid, and superoxide dismutase (SOD)). For this purpose, multilamellar liposomes were prepared. Curcumin was added into the lipid bilayer while ascorbic acid and SOD were placed into the aqueous phase. The influence of preparation technique and surface charge were also investigated. Vesicles were characterised and free radical scavenging potential was determined. From stability study, ascorbic acid showed better stabilising effect. These co-loaded liposomes also exhibited potential radical scavenging activity where ascorbic acid played a key role. From the study of different preparation techniques and charge, we concluded that cationic liposomes made by Thin Layer Evaporation following extrusion offered the best physicochemical and stability properties. A dual mechanism of these liposomes implies the chemical stabilisation of levodopa (dose reduction) and the antioxidant effect, with a preventive effect on Parkinson's disease.

Método Avenzoar para la implantación racional de la atención farmacéutica en la farmacia comunitaria / Avenzoar method for implementation of pharmaceutical care in community pharmacy

Introducción: La evolución de la atención farmacéutica en España, el desarrollo de las tecnologías de la información y la comunicación, los proyectos de receta electrónica, la aparición de publicaciones como el Foro de Atención Farmacéutica, el desarrollo del Bot Plus y su integración con los programas de gestión de las farmacias comunitarias nos han permitido definir una metodología de trabajo en atención farmacéutica (AF), estratificada y selectiva. Metodología: 1. Identificar el paciente destinatario del tratamiento. 2. Dispensación propiamente dicha. 3. Definición del perfil farmacoterapéutico de la farmacia. 3.1. Grupos terapéuticos. 3.2. Indicaciones terapéuticas. 4. Definición de patologías diana. 4.1. Relevancia numérica. 4.2. Relevancia terapéutica. 5. Definición del potencial de seguimiento farmacoterapéutico (SFT) de la farmacia comunitaria. 6. Elección de pacientes diana. 7. Ofrecimiento del servicio de SFT. Resultados: En las cuatro farmacias comunitarias (FC) participantes se definió el perfil farmacoterapéutico a partir de los grupos terapéuticos a nivel 1. A partir de aquí dichas farmacias definieron sus respectivas patologías diana y los posibles pacientes a los que ofrecer el servicio. Se basan en dichos resultados para establecer la formación de sus profesionales. Conclusiones: La metodología Avenzoar parte del conocimiento del paciente mediante el registro sistemático de las dispensaciones realizadas. Permite definir el perfil farmacoterapéutico de los pacientes. Permite decidir el nivel de implicación con el seguimiento de cada paciente según criterios previamente definidos. La metodología Avenzoar es compatible y complementaria con cualquier metodología de seguimiento farmacoterapéutico (AU)

Introduction: The evolution of Pharmaceutical Care in Spain, the development of ICTs, e-prescribing projects, Bot Plus development and its integration with management programs of community pharmacies has allowed us to define a stratified and selective working methodology in Pharmaceutical Care. Methodology: 1. Identification of the patient 2. Dispensation itself. 3. Definition of the pharmacotherapeutic profile of Pharmacy. 3.1. Therapeutic groups. 3.2. Therapeutic indications. 4. Defining target diseases. 4.1. Numerical relevance. 4.2. Therapeutic relevance. 5. Definition of potential pharmacotherapeutic monitoring of community pharmacy. 6. Selection of target patients. 7. Offering pharmacotherapeutic monitoring service. Results and discussion: In the 4 participating pharmacies the pharmacotherapeutic profile was defined based on the treatment groups at level 1. From here, these pharmacies defined their respective target pathologies and potential patients who offer their services. On the basis of these results, pharmacies can establish their professional training. Conclusion: The Avenzoar methodology is based on the systematic recording of dispensations made to patients. It sets the pharmacotherapeutic profile of patients. It allows you to decide the level of involvement with each patient as previously defined criteria. The Avenzoar methodology is compatible and complementary with any methodology of pharmacotherapeutic monitoring (AU)

Diclofenac salts, part 6: release from lipid microspheres.

The release of diclofenac (20%, w/w) was studied from lipidic solid dispersions using three different chemical forms (acid, sodium salt, and pyrrolidine ethanol salt) and two different lipid carriers (Compritol 888 ATO or Carnauba wax) either free or together with varying amounts (10%-30%, w/w) of stearic acid. Microspheres were prepared by ultrasound-assisted atomization of the molten dispersions and analyzed by scanning electron microscopy, differential scanning calorimetry, and hot stage microscopy. The effects of different formulations on the resulting drug release profiles as a function of pH were studied and the results were discussed. The formulation of the 18 systems and the chemical form of the drug were found to strongly affect the mode of the drug release. The solubility of the chemical forms in the lipid mixture is in the following order: pyrrolidine ethanol salt ≫ acid > sodium salt (according to the solubility parameters), and the nature of the systems thus obtained ranges from a matrix, for mutually soluble drug/carrier pairs, to a microcapsule, for pairs wherein mutual solubility is poor. Drug release from microspheres prepared by pure lipids was primarily controlled by diffusion, whereas the release from microspheres containing stearic acid was diffusion/erosion controlled at pH 7.4.

Positively and negatively charged liposomes as carriers for transdermal delivery of sumatriptan: in vitro characterization.

BACKGROUND: The influence of liposome composition, lamellarity, preparation method, and charge on the encapsulation efficiency, size, polydispersity, and surface charge of sumatriptan liposomes was studied. For this purpose, we studied multilamellar, unilamellar, and frozen and thawed liposomes. Positively or negatively charged liposomes were obtained using both phosphatidylcholine and cholesterol, in combination with stearylamine or dicetylphosphate. Liposomal formulations were characterized by confocal laser scanning microscopy and optical microscopy for vesicle formation, morphology, and lamellarity by dynamic laser light scattering for size distribution and polydispersity, and electrophoretic mobility for zeta potential determination. To obtain more information about the sumatriptan encapsulation, dynamic dialysis technique was employed. The sumatriptan amount was quantified by high-performance liquid chromatography. RESULTS: Overall obtained results showed that liposomes may be interesting carriers for sumatriptan succinate. Statistical analysis evidenced that the preparation method does not affect the evaluated characterization parameters. However, the presence of charge inducer agents modified these characteristics. Highest loading efficiency of sumatriptan was exhibited for positively charged liposomes containing 6.58:10.34:3.73 mmolar ratio for phosphatidylcholine : cholesterol : stearylamine. The mean size was affected by the charge inducer, being smaller in positively charged liposomes. Logically, surface charge of liposomes varied as a function of the employed charged agent. Also, interesting results were obtained when vesicles were loaded with sumatriptan, showing a statistical significance between all pairs, comparing the formulations with and without drug. CONCLUSION: Results obtained revealed that the presence of sumatriptan into the vesicles has a different behavior in negatively and positively charged liposomes.

Development of enteric-coated pectin-based matrix tablets for colonic delivery of theophylline.

The present work was aimed at developing a new colonic drug delivery system which takes advantage of the combined approaches of a specifically colon-biodegradable pectin matrix with a pH-sensitive Eudragit S100 polymeric coating. The developed system was able to suitably retard the onset of drug release and to provide a colon-specific delivery, thus overcoming the problems of pectin solubility in the upper gastrointestinal tract and low site-specificity of simple pH-dependent systems. Due to the poor compactability properties of pectin, it was used in mixture with Emdex, a hydrophilic directly-compressible material, in order to make it possible to prepare tablets by direct compression. Theophylline (TP) was used as model drug due to its suitable pharmacokinetic properties for colonic delivery and good absorption in the large intestine. The effects of varying the type of pectin (low and high methoxylated, or amidated), the pectin:Emdex ratio and the level of the pH-dependent polymeric coating on drug release behavior were investigated. Release tests were performed using sequential liquids simulating the physiological variation of pH and the effect of the presence or not of pectinolytic enzymes into the simulated colonic medium was evaluated. Thirty percent (w/w) was the the minimum content of Emdex for obtaining directly compressible tablets with sufficient hardness to withstand the coating process and 27% (w/w) was the minimum coating amount for obtaining an adequate lag time before the onset of drug release. After lag time, linear nearly zero-order profiles were obtained whose slope (i.e. the drug release rate) depended on both the Emdex content and the pectin type. Comparison of the results obtained in the presence or not of pectynolitic enzymes allowed selection of the high methoxylated pectin as the most interesting candidate for specific colonic delivery since it was the least water-soluble and the most susceptible to enzymatic degradation, thus assuring a greater site-specificity of drug release. Finally, the importance of using appropriate dissolution test conditions to adequately characterize the drug release profiles from delivery systems endowed with a microflora-activated drug release triggering mechanism has been demonstrated.