جستجوی مقالات مرتبط با کلیدواژه « release » در نشریات گروه « پزشکی »

Using a blend of herbal and synthetic polymers, the authors aim to extend the release of Sirolimus from the tablets. Sirolimus was used as a model drug, Hydroxy Propyl Methyl Cellulose was used as a synthetic polymer, and mucilage from Hibiscus rosa sinensis leaves was used as a natural polymer in this study. In addition to treating Lymphangioleiomyomatosis damage and suppressing body rejection toward transplanted organs, sirolimus is also an orphan drug. The Sirolimus matrix tablets are made with a combination of H. rosa sinensis leaf mucilage and Hydroxypropyl Methyl Cellulose. We assessed the flow properties of the blend and classified the designed tablets for official and non-official tests, including Sirolimus discharge. Sirolimus matrix tablets have passable pre- and post-formulation parameters with good Sirolimus content. A chemical interaction between Sirolimus and the polymers used in the study was not observed. Researchers also discovered that H. rosa sinensis leaf mucilage can be a good polymer in combination with other polymers for prolonged drug release.

The rupture of flammable materials is one of the significant hazards existing in huge industry. In this study, the rupture of methyl diethanolamine (MDEA) tank in Ilam gas treatment refinery was modeled by PHAST (Process Hazard Analysis Software Tool) software. Distances with high risk was determined in fire and explosion scenarios versus consequence modeling. The results revealed that the catastrophic rupture scenario of MDEA tank in summer climates is the worst case with the highest risk, since in this case, the affected distance is about 2,450 meters for explosion overpressure, and 840 meters for vapor release; thus, these distances should be nonresidential. By considering a bund wall around the tank, the abovementioned distance reduce to 1,860 meters for explosion overpressure and 780 meters for vapor release.

The goal of this research was to design and characterize quercetin microemulsions (MEs) to resolve water solubility issues related to quercetin and improve transcorneal permeation into the eye.

MEs were prepared by the phase diagram method. Oily phase (oleic acid-Transcutol P), surfactant (Tween 80, Span 20), and co-surfactant (propylene glycol) were used to make a quercetin-loaded ME. The size of the droplets, their viscosity, pH, release, flux, and diffusivity were all measured.

Droplet diameters in ME samples ranged from 5.31 to 26.07 nanometers. The pH varied from 5.22 to 6.20, and the release test revealed that 98.06 percent of the medication was released during the first 24 hours. The flux and diffusivity coefficients of the ME-QU-8 formulation were 58.8 µg/cm2.h and 0.009 cm2/h, respectively, which were 8.8 and 17.9 times greater than the quercetin aqueous control (0.2 percent). The maximum percentage of drug permeated through rabbit cornea after five hours was 16.11%.

It is concluded that ME containing quercetin could increase transcorneal permeation and that permeation could be altered by any change in the composition of the ME formulation. This effect might be caused by structural alterations in the cornea caused by ME components.

large reserves of zeolites has been one of the comparative advantages of the country in this field and provides economic justification for its use in a variety of applications, including medical and pharmaceutical fields such as artificial kidney manufacturing, wound dressing, controlled drug release, and bone tissue engineering. In order to protect the drug folic acid (folate) in digestive system acidic environments, zeolite nano carrier (Fe-Co-V/zeolite) was used. After dissolving in ethanol, a certain amount of this drug was placed on zeolite and extracted at different time periods. The release rate of folic acid in similar conditions of stomach and intestine was measured by placing samples of zeolite containing this compound in aqueous solution with an acidic pH of 5.4 and 8.9. The release rate in acidic medium was 17% more than the release of drug in alkaline medium. SEM test was performed to measure the morphology of the pores and to measure the changes in the acidic grade to evaluate the buffering properties of this material. According to the findings of this study, folic acid is very unstable in acidic conditions and use of zeolite, significantly protected the folic acid. This can be attributed to the nature of automatic control of the acidic degree in the tolerable range of the drug (chemical protection). It is also important to note that the highly porous structure of zeolite can affect the initial absorption as well as the release of desired amount of vitamins in an area of chemical protection.

Despite the extensive application of methotrexate (MTX) as a chemotherapeutic agent and an immune system suppressor, its therapeutic implementation has been limited due to its poor pharmacokinetics, saturable cellular transport, and insufficient response in some conditions. These limitations have resulted in the development of novel formulations. A pH-dependent MTX release was indicated in our previous study on polyethyleneimine nano-hydrogels; however, it exhibited a fast drug release in phosphate-buffered saline simulating physiologic pH and tonicity conditions. Thus, the current study was aimed at the synthesis of Zn(MTX)2Cl2 complex (MTX-Zn) to modulate drug loading and release under physiologic condition (pH=7.4). MTX-Zn was synthesized by the hydrothermal method and characterized by TLC, FT-IR spectroscopy, and Eriochrome Black T complexometric titration. MTX-Zn was then loaded into the nano-hydrogels and purified through ultrafiltration. The final product was evaluated by DLS, Zeta-potential, and TEM. The variations in the drug loading and release in acidic (tumor) and physiologic media were assessed through UV-Vis spectrophotometry and dialysis methods, respectively. A 5-fold enhancement was observed in the MTX solubility in the acetate buffer; while the Log D value increased from -0.66 to 0.1 upon Zn2+ complexation, reflecting an augmentation in the drug lipophilicity. The MTX-Zn loaded nano-hydrogels exhibited desirable physicochemical features like a small hydrodynamic diameter of 125.7 nm and low polydispersity (PDI = 0.14). The results indicated that, the release tests indicated that the release of MTX-Zn involves a combination of diffusion and swelling mechanisms. MTX-Zn complexation can be applied in the sustained drug release from the nano-hydrogel formulations.

Finasteride is a pharmaceutical agent that treats hair loss and acne with hormonalpatterns. Due to its poor water solubility, and the smaller surface area in comparison to totalskin surface area, penetration of the drug into hair follicles and skin is low. The aim of thisresearch was to formulate, characterize and evaluate in vitro skin permeability of finasteridemicroemulsions (MEs).

Finasteride MEs were prepared using a pseudo-ternary phase diagram method withan appropriate ratio of oil mixture, surfactant-co-surfactant mixture and water. MEs containing1% finasteride were prepared with a suitable amount of oily phase and surfactant and cosurfactant.The physicochemical properties of these MEs and in vitro skin permeability of MEswere evaluated.

The results showed that the mean droplet size range of ME samples was 5–17 nm andpH was 5.1–5.7. The viscosity of MEs ranged from 86.4–209.6 cps. The drug release profileshowed that 49.510% of the drug was released (ME-F-6) over the 24 hours of the experiment.The kinetics of drug release from all selected MEs were approximately described by Higuchiand first-order modeling. All ME formulations with different compositions and propertiessignificantly increased flux and permeability coefficient from rat skin. The selected MEs exhibit99.9% finasteride after six months of storage.

This study showed that any change in the content and composition of MEs couldchange the physical and chemical properties in addition to ME permeability parameters. TheMEs increased permeability of the skin to finasteride.

Ketorolac tromethamine (KT) is described as a nonsteroidal anti-inflammatory drug (NSAID). Among various NSAIDs, ketorolac tromethamine is commonly used for postoperative and emergency relief of pain. The goal of this study was to describe and assess the in vitro skin permeability of KT microemulsions (MEs). The KT ME formulations were prepared using pseudoternary phase diagrams. Appropriate ratios of oil, S/C mixture, and water were selected, and eight formulations were prepared based on a full factorial design consisting of three variables at two levels. The droplet size, differential scanning calorimetry, pH, stability, viscosity, drug release, and skin permeability were examined in the prepared MEs. The droplet size of ME samples ranged from 28.36 to 81.4 nm, and pH was within the range of 5.1 - 5.7. In addition, the viscosity of MEs was 38 - 135 cps. Considering the drug release profile, 88.04% of the drug (ME-K-1) was released within 24 hours. All ME formulations drastically increased the permeability coefficient and flux in the rat skin. The Jss and Papp parameters were 0.144 mg/cm2.h and 0.0057 cm2/h in the ME-K-8 formulation, respectively (i.e., 8.42 and 8.41 times higher than the control, respectively). Based on the findings, they were visually cleared, and no phase separation was detected. According to the findings, the oil, S/C mixture, and water contents in ME formulations affect physicochemical characteristics and permeation parameters. The selected MEs increased the rate of permeation and permeability coefficient through rat skin. Ideally, MEs should transfer the drug through the skin while maintaining its size and release it into deep layers of the skin. ME formulations may be proper carriers for transdermal ketorolac delivery, although further research is necessary to validate their therapeutic application

Traditionally, Myrtus communis (myrtle) has been used for treatment of several kinds of disorders. However, there are some factors, namely, low solubility and permeability, which restrict use of myrtle extract (ME) in medical applications. Regarding these limitations, the aim of the present study was to develop a new niosomal formulation to enhance ME stability and permeability.
Briefly, several niosomal formulations were prepared by non-ionic surfactants and cholesterol with different molar ratios. Afterward, size, entrapment efficiency (EE%), release and stability of niosomal myrtle extract (nME) were investigated. The effect of ME and nME on viability of 3T3 cells was evaluated using MTT assay. Antibacterial activity of ME and nME was also assessed against staphylococcus aureus, staphylococcus epidermidis, Escherichia coli, Micrococcus luteus, and Bacillus subtilis.
Sizes of niosomes were 5.3±0.3 to 15.9±2.2 µm with 4.1±0.3 to 26.9±1.7 mV zeta potential. The EE% of niosomes was varied from 45.4% to 93.4%. An in vitro release study on F5 formulation (Span60: Tween60: cholesterol (3:3:4 molar ratio)) revealed that about 36.9%, 38.5% and 26.7% of phytoconstituents were released within 12h from acetate cellulose membrane, 0.45 µm, regenerated cellulose membrane, 0.45 µm, and cellophane dialysis sack, 12000 Da, respectively. F5 formulation significantly showed lower toxicity on cells. It had higher antibacterial activity that has been shown by lower MICs and higher zone of inhibition compared to ME.
Overall, F5 formulation in the presence of 4% ME produced stable multi lamellar vesicles with optimal in-vitro release and EE%. This formulation also exhibited better antibacterial activity than ME.

Ketotifen fumarate is a non-bronchodilator anti-asthmatic drug which inhibits the effects of certain endogenous substances known to be inflammatory mediators, and thereby exerts antiallergic activity. The present study describes the formulation of a sustained release nanoparticle (NP) drug delivery system containing ketotifen, using poly (D,L lactide-co-glycolide acid) (PLGA). Biodegradable NPs were prepared using PLGA by a water-in-oil-in-water (w/O/w) double emulsion-solvent evaporation procedure and characterized for drug content , DSC (differential scanning calorimetry, XRD (X-ray diffractionl), FTIR (Fourier transform spectroscopy), particle size, surface morphology using scanning electron microscopy and drug release rate. The effects of different drug-to-polymer ratios on the characteristics of the NPs were investigated. NPs prepared were spherical with a smooth surface. Size of NPs was dependent on the concentration of polymer (10 mg/ml, 754.6 nm). Increasing the external organic phase volume (primary emulsion) resulted in larger particles with higher encapsulation efficiency (55%). The best drug to polymer ratio in the NP was F3 (1:10 ratio) which showed loading efficiency of 55%, and mean particle size of 754.6 nm, respectively. The FTIR, XRPD and DSC results ruled out any chemical interaction between the drug and PLGA. The NPs prepared with low ratio of drug to polymer (1:5) F1 formulation showed faster dissolution rate than those with high drug to polymer ratio (1:10) F3 formulation. In conclusion, by selecting an appropriate level of the investigated parameters, spherical NPs with encapsulation efficiencies higher than 55% and a prolonged drug release over 24h (73.67-90.05%) were obtained.

Gene therapy is a therapeutic approach to deliver genetic material into cells to alter their function in entire organism. One promising form of gene delivery system (DDS) is liposomes. The success of liposome-mediated gene delivery is a multifactorial issue and well-designed liposomal systems might lead to optimized gene transfection particularly in vivo. Liposomal gene delivery systems face different barriers from their site of application to their target, which is inside the cells. These barriers include presystemic obstacles (epithelial barriers), systemic barriers in blood circulation and cellular barriers. Epithelial barriers differ depending on the route of administration. Systemic barriers include enzymatic degradation, binding and opsonisation. Both of these barriers can act as limiting hurdles that genetic material and their vector should overcome before reaching the cells. Finally liposomes should overcome cellular barriers that include cell entrance, endosomal escape and nuclear uptake. These barriers and their impact on liposomal gene delivery will be discussed in this review.

The purpose of the present investigation was to increase the solubility and dissolution rate of celecoxib (CLX) by preparing microcrystals of drug by solvent change precipitation. This procedure was optimized in order to obtain stable and homogeneous particles with a small particle size, high yield and fast dissolution rate. CLX agglomerates were prepared with brij35 (stabilizer agent) using acetone as solvent, water as non-solvent, respectively. The agglomerates were characterized by DSC, XRD, FTIR studies. A full-factorial design was employed to study the effect of independent variables, the amounts of stirring rate (X1), volume of organic solvent (X2), volume of aqueous solvent (X3), time of stirring (X4), concentration of Brij (X5), concentration of Tween 80 (X6), concentration of HPMC (X7) on dependent variables, particle size (PS), drug content (DC), drug released after 15 min (Q15), crystal yield (CY), Gibbs free energy change (ΔG°tr), antalpy change (ΔH) and saturated solubility (Ss). The DSC and FTIR results indicated the absence of any interactions between drug and stabilizers. These studies showed a decrease in crystalinity in agglomerates. The crystals exhibited significantly improved micromeritic properties compared to pure drug. The drug content and crystal yield were in the range of 32.84-48.22% and 64.55-83.33% with all formulations, respectively. The solubility and drug release rates increased with an increase in concentration of stabilizer. The results show that microcrystals of the drug in stabilizer considerably enhanced the dissolution rate.

Polysaccharide mucilage derived from the seeds of Ocimum basilicum L. (family Lamiaceae) was investigated for use in matrix formulations containing propranolol hydrochloride. Basil mucilage was extracted and several tablets were formulated. The effect of mucilage on drug release rate was evaluated in comparison with tablets containing two kinds of hydroxypropyl methylcellulose (HPMC K4M and HPMC K100M) as standard polymer. The release data were fitted to several models for kinetic evaluation. The results showed that hardness decreased and friability of tablets increased as the concentration of mucilage increased. The rate of release of propranolol HCl from O. basilicm mucilage matrices was mainly controlled by the drug: mucilage ratio. Drug release was slower from the HPMC K4M and HPMCK100M containing tablets compared to the mucilage containing matrices than the drug release from matrices containing O. basilicum seed mucilage in similar ratios. Formulations containing O. basilicm mucilage were found to exhibit suitable release pattern. The results of kinetic analysis showed that in tablets containing O. basilicm mucilage the highest correlation coefficient was achieved with the zero order model. The swelling and erosion studies revealed that, as the proportion of mucilage in tablets was increased, there was a corresponding increase in percent swelling and a decrease in percent erosion of tablets.

Development of new drug carriers would be an interesting approach if it allowed increased efficacy of antibiotics and a reduction in doses, thus reducing the risk of developing resistance. As with most drug carriers, niosomes have been used to improve the selective delivery and the therapeutic index of antimicrobial agents. In this study, different formulation of niosomes containing ciprofloxacin (CPFX), Span (20, 60 or 80), Tween (20, 60 or 80) and cholesterol were prepared by film hydration method. The release of the drug from different formulations was studied by using Franz diffusion cell. The niosomes were further characterized by optical microscopy and particle size analysis, and their antimicrobial activity was evaluated. Size of the niosomes was significantly dependent on the amount of cholesterol and surfactant type and varied from 8.56 to 61.3 mm. The entrapment efficiency of CPFX niosomes prepared by remote loading was more than 74%. Niosomes composed of Span/Tween 60 provided a higher CPFX release rate than other formulations. The obtained results indicated a diffusion-based mechanism for drug leakage through bilayers. All formulations presented more antibacterial activity as compared to free CPFX solution. Niosomal CPFX appears to be a promising approach in the management of bacterial infections, especially ophthalmic ones, and should be further evaluated by in vivo experiments.

Loss of motion is a well-known complication after elbow trauma and in severe cases, arthrolysis of elbow is the procedure of choice. The posterior approach might have some advantages especially in post-traumatic patients who have undergone the same surgical approach in the past.. The aim of this study was to evaluate the short-term outcomes of elbow arthrolysis through posterior approach. Moreover, we assessed the effect of operation on the patients’ quality of life.. Patients and During a retrospective-cohort study, the medical records of 14 patients (12 men, two women) whose range of movement had been limited post-traumatically and had undergone elbow arthrolysis with posterior approach were reviewed. Before intervention, the patients had a flexion less than 100 degrees or an extension lag of 30 degrees or more. For evaluation of the final outcomes, they were invited to participate in our study and the final range of motion, visual analogue score (VAS), disability of arm, shoulder and hand (DASH), Mayo elbow score (MES) and short form health survey (SF-36) scores were measured in the patients.. Mean age of the participants was 28.7 years. The interval from initial injury and arthrolysis was 16 months and the patients were followed for 14 months. The mean range of motion in patients before surgery was 35.8 degrees, which was increased to a mean of 108.9 after the surgery, indicating a 73.1 degrees improvement. The means of VAS, DASH, Mayo elbow and SF-36 scores in the patients were 1.6, 34, 68 and 43, respectively. A significant inverse correlation was found between the preoperative range of motion and final range of motion.. According to our results, elbow arthrolysis through posterior approach could be an effective technique with low complications. Since the final range of motion improved significantly, it might be a valuable method in promoting the patients’ quality of life..

Drug delivery via buccal mucosa by means of buccoadhesive formulations offer distinct advantages over peroral administration. Recently, plant gums and exudates have been screened for their use as pharmaceutical adjuvants. The aim of this study is to evaluate matrix tablets containing Plantago psyllium seed mucilage in addition to carbopol as a mucoadhesive agent, and propranolol hydrochloride as a model drug. Mucoadhesive tablets of propranolol were formulated using Plantago psyllium mucilage and Carbopol 934P. The swelling, erosion, mucoadhesion force, in vitro drug release were studied. Interaction between drug and polymers were investigated by DSC thermograms and FT-IR spectra. The bioadhesion strength of formulations containing mucilage and carbopol was more than tablets containing mucilage alone. The results also showed that bioadhesive strength increased with increase in the amount and viscosity of polymers. As the amount of mucilage increased from 6.25% per tablet (F1) to 43.75% (F7) initial release as well as drug release in latter hours was increased in most cases. Combination of Plantago psyllium mucilage and Carbopol 934P modified the release rate and kinetic. The kinetic of drug release has changed by increase in amount of mucilage in these formulations. DSC and FT-IR studies showed no interaction between drug and formulations macromolecules. The use of Plantago psyllium mucilage in addition to carbopol can optimize the drug release in propranolol HCl buccoadhesive tablets.

The potential of polymeric nano particles as an ocular drug delivery system has been explored by a colloidal system consisting of an aqueous suspension of nano particles. These nanoparticles can be rapidly fabricated under extremely mild conditions with their ability to incorporate bioactive compounds. In present study the preparation and characterization of the novel crosslinked poly N-isopropylacrylamide-based micellar nano particles have been reported. Poly Nisopropylacrylamide- acrylic acid-hydroxyethyl methacrylate (NIPAAM-AA-HEM) copolymer was prepared by free radical copolymerization of monomers in 1, 4-dioxane under N2 atmosphere. Triethylene glycol dimethacrylate (TEGDM) was used as a novel cross-linking agent. For preparation of drug-loaded nano particles, indomethacin got directly loaded into the hydrophobic core of micelles. Drug incorporation efficiency was expressed as drug content (DL %). In-vitro indomethacin release rate was tested, too. The chemical structures of cross linked polymers were confirmed by FT-IR and 1H- NMR spectroscopies. The particl size analyzer data represented that the particles has mean sizes between 200-470 nm. The maximum swelling ratio of hydrogel occurred at 10 min at 37 ˚C and pH 1.0 and at 125 min at 20 ˚C and pH 1.0. For both synthesized co-polymeric preparations, a progressive increase of drug release rate was observed as a function of drug-polymer ratio. The prepared nano particles were stable in an aqueous solution and maintained their physical characteristics such as particle size and drug loading content during seven days of storage. The results clearly demonstrated that developed poly N-isopropylacrylamide based formulation showed suitable type of release behavior over 24 h periods. The developed system is thus a viable alternative to conventional ocular drop formulations because it prevents the rapid drainage as in case of mucoadhesive property of the copolymer.