Preparation and in vitro evaluation of evening primerose-based nanoemulsion for the treatment of acne

Introduction: Evening primrose oil is a rich source of linoleic acid and gamma-linolenic acids and can be quite beneficial for reducing the inflammation caused by acne. Besides, by restoreing  hormonal balance, evening primrose oil can prevent acne flare ups in women. Among different strategies of delivering oils, nanoemulsions possess improved transdermal and dermal delivery properties in vitro and in vivo. Nanoemulsions, transparent dispersions of oil and water stabilized by an interfacial film of surfactant having the droplet size less than 200 nm, are thermodynamically stable. The aim of the present study is to develop and optimize an evening primrose oil-based nanoemulsion and investigate its physicochemical properties intended for topical applications.   Methods and Results: The nanoemulsions were prepared by stepwise addition of water to the mixture of Tween 80 and evening primerose oil (as surfactant and oil phase) followed by homogenization and sonication.  The mean droplet size, polydispersity index, zeta potential and short and long term stability properties of the optimized preparation were evaluated. The optimized nanoemulsion was composed of 20% tween 80, 5% evening primerose oil and 75% water. The results showed that the mean particle size of optimized nanoemulsion was 164 nm with a uniform size distribution (PDI< 0.3) and It had a zeta potential of -0.28. The aformentioned nanoemulsion showed the ideal physicochemical stability in a 90 days period Conclusions: According to the results of size, zeta potential and stability tests, incorporation of evening primerose oil into a nanoemulsion formulation can be a promising tool for topical administration of this anti-acne medicine. nanoemulsion appears to be a good choice for the treatment of acne and other skin disorders including eczema and psoriasis and may also be used as a vehicle to carry other lipophilic drugs for more effective treatment against acne

Optimization of a Self-microemulsifying Drug Delivery System for Oral Administration of the Lipophilic Drug, Resveratrol: Enhanced Intestinal Permeability in Rat

Purpose: This study aimed to formulate Resveratrol, a practically water-insoluble antioxidant in a self-microemulsifying drug delivery system (SMEDDS) to improve the solubility, release rate, and intestinal permeability of the drug. Methods: The suitable oil, surfactant, and co-surfactant were chosen according to the drug solubility study. Utilizing the design of experiment (DoE) method, the pseudo-ternary phase diagram was plotted based on the droplet size. In vitro dissolution study and the single-pass intestinal perfusion were performed for the investigation of in vitro and in-situ permeability for drugs formulated as SMEDDS in rat intestine using High-Performance Liquid Chromatography. Results: Castor oil, Cremophor RH60, and PEG 1500 were selected as oil, surfactant, and co-surfactant. According to the pseudo-ternary phase diagram, nine formulations developed microemulsions with sizes ranging between 145-967 nm. Formulations passed the centrifuge and freeze-thaw stability tests. The optimum formulation possessed an almost 2.5-fold higher cumulative percentage of in vitro released resveratrol, in comparison to resveratrol aqueous suspension within 120 minutes. The results of the in-situ permeability study suggested a 2.6-fold higher intestinal permeability for optimum formulation than that of the resveratrol suspension. Conclusions: SMEDDS can be considered suitable for the oral delivery of resveratrol according to the observed increased intestinal permeability, which could consequently enhance the bioavailability and therapeutic efficacy of the drug

A study on enhanced intestinal permeability of clarithromycin nanoparticles

The main objective of the present study was to determine the permeability of clarithromycin (CLA)-PLGA nanoparticles using single-pass intestinal perfusion technique in rats. Clarithromycin nanoparticles were prepared by nano-precipitation according to the modified quasi emulsion solvent diffusion technique and evaluated for their physicochemical characteristics. Permeability coefficients (Peff) in anaesthetized rats were determined at 3 different concentrations. Drug solution or suspensions in PBS was perfused through a cannulated jejunal segment and samples were taken from outlet tubing at different time points up to 90 min. Microbiological assay of CLA and phenol red in the samples were analyzed using an agar well diffusion procedure and HPLC method respectively. The average particle size of prepared nanoparticles was 305 ± 134 nm. The mean Peff of CLA solution in concentrations of 150, 250 and 400 µg/mL was found to be 1.20 (±0.32) ×10-3, 9.62 (±0.46) ×10-4, and 1.36 (±0.95) ×10-3 cm/sec, respectively. The corresponding values for the same concentration of nanoparticles were found to be 2.74 (±0.73) ×10-3, 2.45 (±0.88) ×10-3, and 3.68 (±0.46) ×10-3 cm/s, respectively. The two-tailed Student’s t-test showed that the intestinal permeability of CLA nanoparticle suspensions in prepared concentrations were significantly increased in comparison with its solution.O objetivo principal do presente estudo foi determinar a permeabilidade de nanopartículas de claritromicina (CLA)-PLGA, utilizando a técnica de perfusão intestinal de passo único em ratos. As nanopartículas de claritromicina foram preparadas por nanoprecipitação, de acordo com a técnica modificada de difusão de solvente quase-emulsão, e suas características físico-químicas avaliadas. Os coeficientes de permeabilidade (Peff) em ratos anestesiados foram determinados em três concentrações diferentes. A solução, ou suspensões, do fármaco em PBS foi perfundida através do segmento de jejuno canulado e as amostras foram tomadas do tubo externo em diferentes tempos até 90 minutos. Os ensaios microbiológico de CLA e de vermelho de fenol das amostras foram realizados, utilizando-se o procedimento de difusão em poço de ágar e de CLAE, respectivamente. O tamanho médio das partículas das nanopartículas preparadas foi de 305 ± 134 nm. O Peff médio da solução de CLA em concentrações de 150, 250 and 400 µg/mL foi de 1.20(±0.32)×10-3, 9.62(±0.46)]×10-4 e de 1.36(±0.95)×10-3 cm/s, respectivamente. O valor correspondente para a mesma concentração de nanopartículas foi de 2.74 (±0.73)×10-3, 2.45(±0.88)×10-3 e de 3.68 (±0.46)×10-3 cm/s, respectivamente. O teste t de Student com duas variáveis mostrou que a permeabilidade intestinal das suspensões de nanopartículas de CLA nas concentrações preparadas foram significativamente aumentadas em comparação com sua solução

Development and Validation of an HPLC Method for the Analysis of Sirolimus in Drug Products

Purpose: The aim of this study was to develop a simple, rapid and sensitive reverse phase high performance liquid chromatography (RP-HPLC) method for quantification of sirolimus (SRL) in pharmaceutical dosage forms. Methods: The chromatographic system employs isocratic elution using a Knauer- C18, 5 mm, 4.6 × 150 mm. Mobile phase consisting of acetonitril and ammonium acetate buffer set at flow rate 1.5 ml/min. The analyte was detected and quantified at 278nm using ultraviolet detector. The method was validated as per ICH guidelines. Results: The standard curve was found to have a linear relationship (r2 > 0.99) over the analytical range of 125–2000ng/ml. For all quality control (QC) standards in intraday and interday assay, accuracy and precision range were -0.96 to 6.30 and 0.86 to 13.74 respectively, demonstrating the precision and accuracy over the analytical range. Samples were stable during preparation and analysis procedure. Conclusion: Therefore the rapid and sensitive developed method can be used for the routine analysis of sirolimus such as dissolution and stability assays of pre- and post-marketed dosage forms

Sleep paralysis in medieval Persia – the Hidayat of Akhawayni (?–983 AD)

Among the first three manuscripts written in Persian, Akhawayni’s Hidayat al-muta’allemin fi al-tibb was the most significant work compiled in the 10th century. Along with the hundreds of chapters on hygiene, anatomy, physiology, symptoms and treatments of the diseases of various organs, there is a chapter on sleep paralysis (night-mare) prior to description and treatment of epilepsy. The present article is a review of the Akhawayni’s teachings on sleep paralysis and of descriptions and treatments of sleep paralysis by the Greek, medieval, and Renaissance scholars. Akhawayni’s descriptions along with other early writings provide insight into sleep paralysis during the Middle Ages in general and in Persia in particular