Optical Properties of Methyl Orange-Doped Droplet and Photodynamic Therapy of Staphylococcus aureus.

Dye-doped droplets are known as mixtures of dyes with uniform solutions of water droplets in a continuous phase of oils with surfactants. To observe the relationship between water droplet structures and surfactant types on optical properties of dyes, a mixture of methyl orange (MO)-doped droplet prepared with benzane and hexane as oils and sodium bis(2-ethylhexyl) sulfosuccinate (AOT) as a surfactant was thus examined using Z-scan instrument, spectrophotometer, and fluorimeter in the present study. The findings revealed that nonlinear refractive (NLR) index, nonlinear absorption (NLA) coefficient, as well as fluorescence intensity of the MO had enhanced following a reduction in the droplet water content induced by changes in the non-centrosymmetric charge density distribution of this pH indicator. Moreover, the MO-doped droplet in a continuous phase of benzene investigated by 1H nuclear magnetic resonance (NMR) spectroscopy indicated that the MO had been located in the droplet in the vicinity of the hydrophilic part of the surfactant. Furthermore, the MO-doped droplets along with laser radiation were employed to perform antibacterial photodynamic therapy (APDT) of Staphylococcus aureus (S. aureus). It was ultimately concluded that the bacteria colony had also extremely diminished in the group treated by the MO-doped droplet.

Evaluation of synthetic zeolites as oral delivery vehicle for anti-inflammatory drugs.

OBJECTIVES: In this research, zeolite X and zeolite Y were used as vehicle to prepare intestine targeted oral delivery systems of indomethacin and ibuprofen. MATERIALS AND METHODS: A soaking procedure was implemented to encapsulate indomethacin or ibuprofen within synthetic zeolites. Gravimetric methods and IR spectra of prepared formulations were used to assess drug loading efficiencies into zeolite structures. Scanning Electron Microscopy (SEM) was also utilized to determine morphologies changes in synthetic zeolites after drug loading. At the next stage, dissolution studies were used to predict the in vivo performance of prepared formulations at HCl 0.1 N and PBS pH 6.5 as simulated gastric fluid (SGF) and simulated intestine fluid (SIF), respectively. RESULTS: Drug loadings of prepared formulations was determined between 24-26 % w/w. Dissolution tests at SGF were shown that zeolites could retain acidic model drugs in their porous structures and can be able to limit their release into the stomach. On the other hand, all prepared formulations completely released model drugs during 3 hr in simulated intestine fluid. CONCLUSION: Obtained results indicated zeolites could potentially be able to release indomethacin and ibuprofen in a sustained and controlled manner and reduced adverse effects commonly accompanying oral administrations of NSAIDs.

Hydrogels composed of cyclodextrin inclusion complexes with PLGA-PEG-PLGA triblock copolymers as drug delivery systems.

Although conventional pharmaceuticals have many drug dosage forms on the market, the development of new therapeutic molecules and the low efficacy of instant release formulations for the treatment of some chronic diseases and specific conditions encourage scientists to invent different delivery systems. To this purpose, a supramolecular hydrogel consisting of the tri-block copolymer PLGA-PEGPLGA and α-cyclodextrin was fabricated for the first time and characterised in terms of rheological, morphological, and structural properties. Naltrexone hydrochloride and vitamin B12 were loaded, and their release profiles were determined.

Sustained delivery of amphotericin B and vancomycin hydrochloride by an injectable thermogelling tri-block copolymer.

Because traditional drug delivery poses many disadvantages such as poor compliance of patients and a drug plasma level variation, novel drug delivery systems containing controlled release drug vehicles become attractive. In this study, a kind of tri-block copolymer consisting of polycaprolactone (PCL) and poly(ethylene glycol) (PEG), PCL-PEG-PCL, were synthesized by a rapid microwave-assisted and a conventional synthesis method to form an in situ gelling system that provides a controlled release of drugs over a long period of time. Copolymer characterization was performed using a gel permeation chromatography, the (1)H-NMR, and a phase transition behavior evaluation. Vancomycin hydrochloride and amphotericin B were used as drug models here. This study confirmed that the synthesis of the copolymer using microwave irradiation was the most effective method to prepare this smart copolymer. Results also demonstrated the better performance of the microwave-synthesized copolymer regarding its phase behavior. It was shown that gelatin temperatures were also affected by the hydrophilicity of the drug model, the copolymer concentration, and the media. It was indicated that the hydrogels could sustain the delivery of model drugs for about 17 to 20 days. As the drugs used in this study were both large molecules and the main release mechanism was copolymer bulk erosion rather than simple diffusion, the effect of drug and copolymer concentration on the drug release profile was not so significant. LAY ABSTRACT: Different studies have been carried out to improve drug delivery systems. Smart drug vehicles such as thermoresponsive and in situ forming hydrogels made of tri-block copolymers are promising systems in this field. Thermoresponsive hydrogels can release loaded molecules in response to the changing temperature. In situ forming hydrogels are the kind of thermoresponsive materials that are injectable fluid (sol) at room temperature and gel at body temperature. Pharmaceuticals release gradually from the gel over long periods of time. Here we investigated the in situ forming hydrogel based on poly(caprolactone)-poly(ethylene glycol)-poly(caprolactone) as a drug delivery system. Vancomycin hydrochloride and amphotericin B were used in this study as a model. The results indicated that this system can control release pattern of drug perfectly for approximately 20 days.

Biodegradable In Situ Gel-Forming Controlled Drug Delivery System Based on Thermosensitive Poly(ε-caprolactone)-Poly(ethylene glycol)-Poly(ε-caprolactone) Hydrogel.

Traditional drug delivery systems which are based on multiple dosing regimens usually pose many disadvantages such as poor compliance of patients and drug plasma level variation. To overcome the obstacles of traditional drug formulations, novel drug delivery system PCL-PEG-PCL hydrogels have been purposed in this study. Copolymers were synthesized by rapid microwave-assisted and conventional synthesis methods. Polymer characterizations were done using gel permeation chromatography and (1)H-NMR. Phase transition behavior was evaluated by inverting tube method and in vitro drug release profile was determined using naltrexone hydrochloride and vitamin B(12) as drug models. The results indicated that loaded drug structure and copolymer concentration play critical roles in release profile of drugs from these hydrogels. This study also confirmed that synthesis of copolymer using microwave is the most effective method for synthesis of this kind of copolymer.

Preparation and investigation of sustained drug delivery systems using an injectable, thermosensitive, in situ forming hydrogel composed of PLGA-PEG-PLGA.

In situ gelling systems are very attractive for pharmaceutical applications due to their biodegradability and simple manufacturing processes. The synthesis and characterization of thermosensitive poly(D,L-lactic-co-glycolic acid) (PLGA)-polyethylene glycol (PEG)-PLGA triblock copolymers as in situ gelling matrices were investigated in this study as a drug delivery system. Ring-opening polymerization using microwave irradiation was utilized as a novel technique, and the results were compared with those using a conventional method of polymerization. The phase transition temperature and the critical micelle concentration (CMC) of the copolymer solutions were determined by differential scanning calorimetry and spectrophotometry, respectively. The size of the micelles was determined with a light scattering method. In vitro drug release studies were carried out using naltrexone hydrochloride and vitamin B12 as model drugs. The rate and yield of the copolymerization process via microwave irradiation were higher than those of the conventional method. The copolymer structure and concentration played critical roles in controlling the sol-gel transition temperature, the CMC, and the size of the nanomicelles in the copolymer solutions. The rate of drug release could be modulated by the molecular weight of the drugs, the concentration of the copolymers, and their structures in the formulations. The amount of release versus time followed zero-order release kinetics for vitamin B12 over 25 days, in contrast to the Higuchi modeling for naltrexone hydrochloride over a period of 17 days. In conclusion, PLGA-PEG1500-PLGA with a lactide-to-glycolide ratio of 5:1 is an ideal system for the long-acting, controlled release of naltrexone hydrochloride and vitamin B12.

(E)-2-tert-Butyl-6-[(naphthalen-1-yl)imino-meth-yl]phenol.

The asymmetric unit of the title Schiff base compound, C(21)H(21)NO, contains two crystallographicaly independent mol-ecules. The dihedral angles between the naphthalene mean plane and the benzene ring are 29.28 (8) and 26.92.(8)° in the two mol-ecules. An intra-molecular O-H⋯N hydrogen bond and weak intra-molecular C-H⋯O hydrogen bonds stabilize the structure of each independent mol-ecule.