Preparation and Characterization of Metoprolol Controlled-Release Solid Dispersions

In recent years, great attention has been paid to using solid dispersions to make sustained-release drugs. The objective of this study is to produce sustained-release systems of metoprolol tartrate using solid dispersion techniques and to evaluate their physicochemical characteristics. The solid dispersions were produced by melting and solvent methods, containing 7%, 15%, or 25% of the drug and different ratios of Eudragit RLPO and RSPO in ratios of 0:10, 3:7, 5:5, 7:3, and 10:0. Drug release profiles were determined by USP XXIII rotating paddle method in phosphate buffer solution (pH 6.8). XRD, DSC, IR, and microscopic observations were performed to evaluate the physical characteristics of solid dispersions. Results showed that the drug release from dispersions was at a slower rate than pure drug and physical mixtures. Moreover, the formulations containing greater ratios of Eudragit RSPO showed slower release rates and smaller DE_8% but larger mean dissolution time than those containing greater ratios of Eudragit RLPO. Dispersions with particle size of less than 100 μm containing 7% of metoprolol and Eudragit RL:RS 5:5 (solvent method) and those with the ratio of 3:7 (melting method) had similar release pattern to Lopressor® sustained-release tablets by zero-order and Higuchi kinetics, respectively.     

Preparation and in vitro characterization of piroxicam enteric coated pellets using powder layering technique

The objective of this study was to develop piroxicam enteric coated pellets using nonpareil seeds by powder layering technique to minimize its gastrointestinal adverse effects. Inert seeds were prepared by incorporating sugar, Avicel PH 101 and lactose. The obtained cores were then treated by PVP 10 w/v % solution using centrifugal granulator (CF-granulator) and then coated with micronized piroxicam using HPMC solution (8 w/v %) as binder. The piroxicam pellets were finally coated with different polymers (Eudragit L30D-55, Eudragit L100, Eudragit NE30D, Acryleze, or mixture of Eudragits L30D-55 and NE30D) and plasticizers (triethyl citrate and polyethylene glycol 6000). Results showed that Eudragit L30D-55 with 3% weight gain accompanied with TEC produced suitable enteric coated pellets.     

Pneumatic Balloon Dilation Therapy Is as Effective as Esophagomyotomy for Achalasia

For many years different treatments have been used for achalasia. However, esophagomyotomy (ESM) and pneumatic balloon dilation (PBD) have been considered the treatments of choice. Despite new research, some controversies still exist. We compared patients who underwent open ESM (n=19) with those who underwent PBD (n=45). Data on age, gender, pre- and postprocedure symptoms, clinical manifestations at the time of research, clinical relief, type of surgery, and costs were collected via questionnaire. Open ESMs were performed by two expert surgeons, and PBDs were performed by one gastroenterologist. There was no significant difference in clinical symptoms and in patient satisfaction between the groups before and after the procedures except for chest pain. Clinical relief status (excellent, good, moderate, or poor) was comparable (26%, 42%, 15%, 15% for open ESM group and 40%, 20%, 24%, 15% for PBD group). Postprocedure complications were not significantly different between the two groups. Clinical rates of relapse for open ESM and PBD groups were 38.6% and 25%, respectively. There were no serious complications. There was no significant difference between the clinical outcomes of the two methods of achalasia treatment. Considering other important factors such as a shorter period of hospitalization, fewer sick days off, risk of general anesthesia, and cosmetic sequels, PBD is preferable for the majority of patients.     

Optimization of self-assembling properties of fatty acids grafted to methoxy poly(ethylene glycol) as nanocarriers for etoposide

The objective of this work was to study the effect of fatty acid chain length grafted to methoxy poly(ethylene glycol) (mPEG) on self assembling properties of micelles for etoposide delivery. Three amphiphilic copolymers were synthesized using mPEG, myristic acid, stearic acid and behenic acid through an esteric linkage. The particle size and zeta potential of the micelles were determined by the dynamic light scattering method. Etoposide was loaded into micelles by film casting using various drug/polymer ratios. Drug release was studied by the dialysis method. The structure of copolymers was confirmed by (1)H NMR and FTIR. Central micellar concentration (CMC) measurements showed that the longer hydrophobic chains formed more thermodynamically stable micelles. Among the prepared copolymers, etoposide showed the highest solubility in the mPEG-behenic copolymer. Drug loading efficiency depended on the hydrophobic chain length and drug/polymer ratio. The highest drug loading efficiency was found in mPEG-myristic micelles with 1:20 drug/polymer ratio. Micelles released 80 % of loaded drug within about 5 h.     

Piroxicam nanoparticles for ocular delivery: Physicochemical characterization and implementation in endotoxin-induced uveitis

To investigate the anti-inflammatory impacts of piroxicam nanosuspension, in the current investigation, piroxicam:Eudragit®RS100 nanoformulations were used to control inflammatory symptoms in the rabbits with endotoxin-induced uveitis (EIU). The nanoparticles of piroxicam:Eudragit®RS100 was formulated using the solvent evaporation/extraction technique. The morphological and physicochemical characteristics of nanoparticles were studied using particle size analysis, X-ray crystallography, differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). Drug release profiles were examined by fitting the data to the most common kinetic models. Selected nanosuspensions were used to assess the anti-inflammatory impacts of piroxicam nanoparticles in the rabbits with EIU. The major symptoms of EIU (i.e. inflammation and leukocytes numbers in the aqueous humor) were examined. All the prepared piroxicam formulations using Eudragit®RS100 resulted in a nano-range size particles and displayed spherical smooth morphology with positively charged surface, however, the formulated particles of drug alone using same methodology failed to manifest such characteristics. The Eudragit®RS100 containing nanoparticles displayed lower crystallinity than piroxicam with no chemical interactions between the drug and polymer molecules. Kinetically, the release profiles of piroxicam from nanoparticles appeared to fit best with the Weibull model and diffusion was the superior phenomenon. The in vivo examinations revealed that the inflammation can be inhibited by the drug:polymer nanosuspension more significantly than the microsuspension of drug alone in the rabbits with EIU. Upon these findings, we propose that the piroxicam:Eudragit®RS100 nanosuspensions may be considered as an improved ocular delivery system for locally inhibition of inflammation.     

The promise of chitosan microspheres in drug delivery systems

Chitosan is a partially deacetylated polymer obtained from the alkaline deacetylation of chitin, which is a glucose-based, unbranched polysaccharide that occurs widely in nature as the principal component of exoskeletons of crustaceans and insects, as well as of the cell walls of some bacteria and fungi. Chitosan exhibits a variety of physicochemical and biological properties resulting in numerous applications in fields such as waste water treatment, agriculture, fabric and textiles, cosmetics, nutritional enhancement and food processing. In addition to its lack of toxicity and allergenicity, its biocompatibility, biodegradability and bioactivity make it a very attractive substance for diverse applications as a biomaterial in the pharmaceutical and medical fields. This review takes a closer look at the biomedical applications of chitosan microspheres. Based on recent research and existing products, some new and potential future approaches in this fascinating area are discussed.