The effect of strontium carbonate on cross-linking of pectin based free

Introduction: : Recently, considerable attention has been devoted to biopolymers because of their unique properties and high usage in different fields such as pharmaceutical industry, health promotion and cosmetic applications .Pectin is a high-molecular weight and anionic natural heteropolysaccharide extracted from cell walls of higher plants which is non-toxic and biocompatible.(1) A cross-link is a bond that links one polymer chain to another. Strontium (Sr+2) establish covalent bonds (chemical method) and physical interaction (physical method) between anionic pectin chains that makes polymer stronger. Methods and Results: : Firstly, specific amounts of pectin were dissolved in distilled water. Then, a fixed amount of triethyl citrate (1:6 ratio related to total polymer content) was added to solution as a plasticizer. After 24 hour, free film was cross-linked with 1% strontium carbonate solution for 1 minute .For swelling experiment, a piece of dried cross-linked and non cross-linked pectin based free film was weighted and immersed in flasks of dissolution test containing 250 ml of acidic media(PH=1.2) and phosphate buffer media(PH=6.8) at 37 ℃. sampling time was started from 2 minutes to 60 minutes. To quantify the swelling process, the swelling index, Is (%),was calculated(2). Thickness of both cross-linked and non cross linked pectin based free film was 0.16. Is for cross-linked free film in buffer media was 104% and in acidic media was 94%. Non cross-linked free film was ionized in buffer media while Is was 163% for non cross-linked free film in acidic media. Conclusions: Cross-linker greatly reduced the ionization of the free film in phosphate buffer media and resisted against excessive swelling of the free film in acidic media. Due to positive charge of acidic media and negative charge of pectin free film ,more swelling was expected in acidic media versus buffer media. The Cross-linking had no significant effect on thickness. According to investigate the effect of cross-linker on free film , more experiments needed to be done

Alginate Free Films: Cross-linking with Strontium Carbonate

Introduction: Alginates are non-toxic, hydrophilic, biocompatible, biodegradable and low cost polymers which make them suitable for many biomedical applications. Due to their good tissue compatibility, they have been widely used in enhancing the healing process. However, they have limitations in mechanical characteristics and drug release. Adding metal ions could add some features to these films in order to improve their properties. The purpose of this study is to compare alginate blend films cross-linked with different concentrations of strontium in order to submit one as the best in topical applications. Methods and Results:Sodium alginate (2 g/100 g) was first dissolved in 50 mL de-ionized water. Di butyl phthalate (16%w/w) was added as plasticizer. After dissolution, the solution was poured into Petri dishes and dried at 40°C for 24 h. Alginate films were chemically cross-linked by immersing in different concentrations of strontium carbonate (0.1-1-10% w/v) for 1 minute. The films were then dried at oven at 40 °C for 24 h. The swelling test was performed in acidic(HCl 0.1N) and phosphate buffer media (pH=6.8) for 90 minutes. Thickness of alginate film before and after the strontium crosslinking procedure was0.178mm and 0.26 mm, respectively. Swelling index (IS) in acid and buffer media was 280.70% and 263.64%, respectively. Conclusions:The swelling test of cross-linked films has demonstrated satisfying results by increasing in swelling properties, hence promising outcome for wound healing conditions. Also, the results showed pH-responsive swelling behaviors with surprisingly more swelling in acidic media compared to buffer

New Natural Marine Antacid Drug from Cuttlebone

Background: Antacids are the most commonly used medications for fast symptomatic relief of gastric disorders. Because of adverse effects, low efficiency and the high cost of some chemical antacids, identifying a natural medicine with high efficiency and low cost seems useful. Therefore, the aim of the present study was to prepare antacid tablets from Cuttlefish bone and assessment of its antacid properties. Methods: 24 different formulations of cuttlefish bone were prepared by direct compression using different fillers (starch, cellulose, lactose, and mixture of those) in different ratios of the drug. Characterization of powders and tablets was done on all formulations and marketed dosage forms (calcium carbonate and Al-Mg). Results: Weight uniformity, hardness, and friability of all formulations were in acceptable range. Tablets prepared by calcined cuttlebone disintegrated in longer time due to their higher hardness which were mostly higher than 5 Kg. Also, disintegration time of formulations 50-50 (lower dose of cuttlebone) was less than other tablets (2 minutes or less). Results of antacid capacity showed that formulations 90-10 and 80-20 raise the acidic pH of the medium above 7.5, which were the same as or more than the capacity of the marketed tablets. Conclusion: Tablets were prepared by 90 or 80% of either calcined or non-calcined cuttlebone showed the highest antacid capacity

Indomethacin electrospun nanofibers for colonic drug delivery: in vitro dissolution studies

Generally, although the conventional drug delivery systems, such as using only pHdependent polymers or time-dependent release systems are popular, the individuals’ variations of physiological conditions usually lead to premature or imperfect drug release from each of these systems. Therefore, a combination of pH- and time-dependent polymers could be more reliable for delivering drugs to the lower GI tract such as colon. To this end, electrospinning method was used as a fabrication approach for preparing electrospun nanofibers of indomethacin aimed for colon delivery. Formulations were prepared based on a 3 2 full factorial design. Independent variables were the drug:polymer ratio (with the levels of 3:5, 4.5:5 and 6:5 w/w) and Eudragit S:Eudragit RS w/w ratio (20:80, 60:40 and 100:0). The evaluated responses were drug release at pH 1.2, 6.4, 6.8 and 7.4. Combinations of Eudragit S (ES), Eudragit RS (ERS) and drug based on factorial design were loaded in 10 ml syringes. 3 Electrospinning method was used to prepare electrospun nanofibers from electrospinning solutions. Conductivity and the viscosity of the solutions were analyzed prior to electrospinning. After collection, the nanofibers were evaluated in terms of morphology and drug release. It was shown that the ratio of drug:polymer and polymer:polymer were pivotal factors to control the drug release from nanofibers. A formulation containing Eudragit S:Eudragit RS (60:40) and drug:polymer ratio of 3:5 exhibited the most appropriate drug release as a colon delivery system with a minor release at pH 1.2, 6.4 and 6.8 and major release at pH 7.4. Nanofibers resulted from this formulation were also more uniform and contained fewer amounts of beads. It was demonstrated that the electrospinning could be regarded as a modern approach for the preparation of colon drug delivery systems leading to marketable products

Prediction of Optimum Combination of Eudragit RS/Eudragit RL/Ethyl Cellulose Polymeric Free Films Based on Experimental Design for Using as a Coating System for Sustained Release Theophylline Pellets

Purpose: The physicochemical properties of free films made from different mixtures of sustained release polymers were investigated, and an optimum formulation coating on drug containing pellets, based on the study of free film was evaluated. Methods: In order to determine the effect of different variables on the permeability and swelling of films and procedure optimization, the experimental design was fulfilled based on the statistical method of a 33 full factorial design, and according to this method 27 formulations were prepared. The films were prepared using casting-solvent evaporation method. Water vapor permeability, the swelling and permeability of free films in both acidic and buffer media, were carried out. Then, the pellets containing theophylline were coated with the optimum formulation. Results: The results of this study demonstrated that an increase in the free film thickness and Eurdragit RS ratio in films lowered the water vapor transmission (WVT), the swelling and the permeability of all formulations, while an increase in the quantity of ethylcellulose, up to a specific ratio (approximately 40%), decreased the permeability and swelling. The most optimum free film formulation was made up of 60% Eudragit RS and 40% ethylcellulose. Conclusion: Pellets coated with a 10% coating level of ethylcellulose and Eudragit RS (4:6) showed suitable release properties and could serve as a favorable sustained release system for theophylline

A review on electrospun nanofibers for oral drug delivery

Nowadays, polymer nanofibers have gained attention due to remarkable characteristics such as high porosity and large surface area to volume ratio. Among their fabrication methods, electrospinning technique has been attracted as a simple and reproducible approach. It is a versatile, simple and cost-effective technique for the production of continuous nanofibers with acceptable characteristics such as high porosity, high surface area to volume ratio, high loading capacity and encapsulation efficiency, delivery of multiple drugs, and enhancement of drug solubility. Due to these properties electrospun nanofibers have been extensively used for different biomedical applications including wound dressing, tissue engineering, enzyme immobilization, artificial organs, and drug delivery. Different synthetic and natural polymers have been successfully electrospun into ultrafine fibers. Using electrospun nanofibers as vehicles for oral drug delivery has been investigated in different release manners- fast, biphasic or sustained release. This article presents a review on application of electrospinning technique in oral drug delivery

Preparation and evaluation of vitamin A nanosuspension as a novel ocular drug delivery

Objective(s): The aim of this study was to prepare a nanosuspension formulation as a new vehicle for the improvement of the ocular delivery of vitamin A. Material and Methods: Formulations were designed based on full factorial design. A high pressure homogenization technique was used to produce nanosuspensions. Fifteen formulations were prepared by the use of different combinations of surfactants Tween 80, benzalkonium chloride and Pluronic and evaluated for pH, particle size, entrapment efficiency, differential scanning calorimetry (DSC), stability and drug release.  Also, Draize test was used to evaluate the irritation of rabbit eye by formulations. Results: All formulations showed a small mean size that is well suited for ocular application. Also it was observed that the particle size decreased with increase in the amount of surfactant. Drug entrapment increased with increasing amount of surfactant. It was shown that initial and final drug release can be controlled by the ratio and the total amount of surfactants, respectively. Conclusion: It was concluded that the use of Tween 80 and Pluronic in the formualtions with a proper ratio does not show eye irritation and could be useful to achieve a suitable nanosuspension of vitamin A as a novel ocular delivery system

A review on curcumin colon-targeted oral drug delivery systems for the treatment of inflammatory bowel disease

Synthetic drugs and monoclonal antibodies are the typical treatments to combat inflammatory bowel disease (IBD). However, side effects are present when these treatments are used, and their continued application could be restricted by the high relapse rate of the disease. One potential alternative to these treatments is the use of plant-derived products. The use curcumin is one such treatment option that has seen an increase in usage in treating IBD. Curcumin is derived from a rhizome of turmeric (Curcuma longa), and the results of studies on the use of curcumin to treat IBD are promising. These studies suggest that curcumin interacts with cellular targets such as NF-κB, JAKs/STATs, MAPKs, TNF-α, IL-6, PPAR, and TRPV1 and may reduce the progression of IBD. Potentially, curcumin can be used as a therapeutic agent for patients with IBD when it reduces the incidence of clinical relapse. This review discusses the strategies utilized in designing and developing an oral colonic delivery dosage form of curcumin

Preparation and Characterization of a Novel Multiparticulate Dosage Form Carrying Budesonide-Loaded Chitosan Nanoparticles to Enhance the Efficiency of Pellets in the Colon

An attempt was made to conquer the limitation of orally administered nanoparticles for the delivery of budesonide to the colon. The ionic gelation technique was used to load budesonide on chitosan nanoparticles. The nanoparticles were investigated in terms of size, zeta potential, encapsulation efficiency, shape and drug release. Then, nanoparticles were pelletized using the extrusion–spheronization method and were investigated for their size, mechanical properties, and drug release. Pellets were subsequently coated with a polymeric solution composed of two enteric (eudragit L and S) and time-dependent polymers (eudragit RS) for colon-specific delivery. All formulations were examined for their anti-inflammatory effect in rats with induced colitis and the relapse of the colitis after discontinuation of treatment was also followed. The size of nanoparticles ranged between 288 ± 7.5 and 566 ± 7.7 nm and zeta potential verified their positive charged surface. The drug release from nanoparticles showed an initial burst release followed by a continuous release. Pelletized nanoparticles showed proper mechanical properties and faster drug release in acidic pH compared with alkaline pH. It was interesting to note that pelletized budesonide nanoparticles released the drug throughout the GIT in a sustained fashion, and had long-lasting anti-inflammatory effects while rapid relapse was observed for those treated with conventional budesonide pellets. It seems that there is a synergistic effect of nanoformulation of budesonide and the encapsulation of pelletized nanoparticles in a proper coating system for colon delivery that could result in a significant and long-lasting anti-inflammatory effect