Oral Sustained Drug Delivery System Research Articles

Plants as pharmaceutical excipients in oral sustained drug delivery systems: A review

Plants and their derivatives have contributed immensely to drug development for their application as medicinal agents or as excipients in preparation of new drug delivery systems. Their use keeps increasing by the day. The rich, yet-to-be fully tapped vegetation available in the African sub-region puts it with great potential to be the next global destination as sources for pharmaceutical excipient. This work reviews published articles on plants and derivatives that have been employed so far in modifying drug delivery. Published articles from databases of PubMed, science direct and google scholar were sourced. Obtained manuscripts were screened for relevance to the topic and currency from reading through the abstract and scanning the body of the work. Gums and mucilages as plant derivatives in their natural form or as changed forms have been well investigated for use in controlled drug delivery. Some of these have been as functional in modifying drug release as many commercially employed excipients in drug delivery. Many plants and plant-derived polymers are generally regarded as safe, easily cultivated, show good functionality as drug additives and can be modified to improve on any less desirable property. Taking advantage of these positive factors will open doors for optimal use of these naturally endowed pharmaceutical excipients

Gastroretentive drug delivery system: A systematic review

Gastroretentive drug delivery system is a novel drug delivery system that has an upper hand due to its ability to maintain prolonged stomach retention and thereby increase the stomach residence time of drugs and also enhance the bioavailability of drugs. Oral sustained drug delivery system is complicated by reduced stomach residence time (GRTs) and erratic stomach emptying time etc. In order to overcome these limitations, various approaches have been proposed to increase the gastric residence of drug delivery systems in the upper part of the gastrointestinal tract peptic ulcer, stomach ulcer, or gastric ulcer, also known as peptic ulcer disease, is a very common chronic stomach disorder that is mainly caused by stomach lining damage. Various factors such as pepsin, gastric acid, H. Pylori, NSAIDs, prostaglandins, mucus, bicarbonate, and mucosal blood flow play an important role in the development of peptic ulcers and so on. In this review article we concentrate on some important mechanisms for the delivery of gastro-retentive drugs (GRDDS) (floating, bioadhesive, high density, swellable, raft forming, and magnetic systems) which will be useful in the treatment of peptic ulcer in different dosage types. This manuscript highlights various developmental approaches, Comparison between Conventional drug delivery systems and Gastro retentive Drug delivery systems, characterization aspects, potential drug candidates, unsuitable drug candidates, List of commercialized gastro-retentive drug delivery system, advantages and applications of gastroretentive systems.

FORMULATION, EVALUATION AND OPTIMIZATION OF RANITIDINE HYDROCHLORIDE FLOATING TABLETS WITH IMPROVED GI ABSORPTION

Oral drug delivery system represents one of the main areas of sustained drug delivery system. Floating drug delivery system related to oral sustained drug delivery system group, which is capable of floating in the stomach for an exteneded period of time. Ranitidine hydrochloride is a histamine H2-receptor antagonist. It is widely prescribed in active duodenal ulcers, gastric ulcers, Zollinger-Ellison syndrome and GERD. A traditional oral sustained release formulation releases most of the drug at the colon, thus the drug should have absorption window either in the colon or throughout the gastrointestinal tract. Ranitidine is absorbed only in the initial part of the small intestine and has 50% absolute bioavailability. The aim of the present research is to provide a gastroretentive system for sustained release of Ranitidine hydrochloride in the upper part of the gastrointestinal tract in the form of floating tablet. Gastroretentive tablets of Ranitidine Hydrochloride were prepared by direct compression technique using polymers like Carbopol, Chitosan, Styrene-divinylbenzene and the mixture of Magnesium stearate as a lubricant, Talc as a glidant and Lactose as fillers. The results of the present research show that the chitosan and carbopol 940 mixed matrices can be used to modify release rates in hydrophilic matrix tablets prepared by direct compression. Incorporation of the highly porous low-density copolymer in the matrix tablets provides densities that are lower than the density of the release medium. 17% w/w low density copolymer (based on the mass of the tablet) was sufficient to achieve proper in vitro floating behavior for at least 8 h. Keywords: Floating drug delivery system, Ranitidine hydrochloride, Gastrointestinal tract, Carbopol, ChitosanÂ

Multilayer encapsulated mesoporous silica nanospheres as an oral sustained drug delivery system for the poorly water-soluble drug felodipine.

We used a combination of mesoporous silica nanospheres (MSN) and layer-by-layer (LBL) self-assembly technology to establish a new oral sustained drug delivery system for the poorly water-soluble drug felodipine. Firstly, the model drug was loaded into MSN, and then the loaded MSN were repeatedly encapsulated by chitosan (CHI) and acacia (ACA) via LBL self-assembly method. The structural features of the samples were studied using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and nitrogen adsorption. The encapsulating process was monitored by zeta-potential and surface tension measurements. The physical state of the drug in the samples was characterized by differential scanning calorimetry (DSC) and X-ray diffractometry (XRD). The influence of the multilayer with different number of layers on the drug release rate was studied using thermal gravimetric analysis (TGA) and surface tension measurement. The swelling effect and the structure changes of the multilayer were investigated to explore the relationship between the drug release behavior and the state of the multilayer under different pH conditions. The stability and mucosa adhesive ability of the prepared nanoparticles were also explored. After multilayer coating, the drug release rate was effectively controlled. The differences in drug release behavior under different pH conditions could be attributed to the different states of the multilayer. And the nanoparticles possessed good stability and strong mucosa adhesive ability. We believe that this combination offers a simple strategy for regulating the release rate of poorly water-soluble drugs and extends the pharmaceutical applications of inorganic materials and polymers.

Alginate encapsulated mesoporous silica nanospheres as a sustained drug delivery system for the poorly water-soluble drug indomethacin

We applied a combination of inorganic mesoporous silica material, frequently used as drug carriers, and a natural organic polymer alginate (ALG), to establish a sustained drug delivery system for the poorly water-soluble drug Indomethacin (IND). Mesoporous silica nanospheres (MSNs) were synthesized using an organic template method and then functionalized with aminopropyl groups through postsynthesis. After drug loading into the pores of aninopropyl functionalized MSNs (AP-MSNs), IND loaded AP-MSNs (IND-AP-MSNs) were encapsulated by ALG through the ionic interaction. The effects of surface chemical groups and ALG layer on IND release were systematically studied using scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption, zeta-potential analysis and TGA analysis. The surface structure and surface charge changes of the ALG encapsulated AP-MSNs (ALG-AP-MSNs) were also investigated. The results showed that sustained release of IND from the designed drug delivery system was mainly due to the blockage effect from the coated ALG. We believe that this combination will help designing oral sustained drug delivery systems for poorly water-soluble drugs.

Poly dimethyl diallyl ammonium coated CMK-5 for sustained oral drug release

A new oral sustained drug delivery system (DDS) involving a combination of inorganic mesoporous material (CMK-5) and organic polymer poly dimethyl diallyl ammonium (PDDA) was established to determine its general suitability for use with poorly water soluble drugs. Nimodipine, carvedilol and fenofibrate, three different drugs with acidic or alkaline properties, were selected as model drugs and loaded into carriers. The physicochemical properties of the drug carriers were systematically studied using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and nitrogen adsorption. The structural body changes of the composites in release medium, with or without additional salts, were also studied using particle sizing systems, nitrogen adsorption and zeta potential measurement in order to investigate the sustained release mechanism of the drugs. The results obtained showed that sustained release of drug from the designed DDS was mainly due to the blockage effect arising from the strong swelling of the coated polymers when in contact with release medium. Additional salts, when they reached a certain level, allowed a dramatic burst release. We believe that our designed sustained DDS provide a new option for water insoluble drugs and can be considered as fundamental for those more sophisticated DDS increasingly required in modern medical treatments.

Novel Chitosan-Functionalized Spherical Nanosilica Matrix As an Oral Sustained Drug Delivery System for Poorly Water-Soluble Drug Carvedilol

A novel spherical nanosilica matrix (SNM) together with chitosan (CTS) encapsulated SNM (CTS-SNM) was developed in order to investigate the feasibility of using chitosan to regulate drug release rate from porous silica and obtain an oral sustained drug delivery system. To achieve this goal, we synthesized a spherical nanosilica matrix (SNM) and incorporated chitosan chains on the SNM surface. Solvent evaporation method was adopted to load the model drug carvedilol into SNM and CTS-SNM. The physicochemical properties of the drug carriers and drug-loaded composites were systematically studied using scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption, X-ray diffraction (XRD), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The structural changes in CTS-SNM in simulated gastrointestinal fluid as well as the relationships between swelling effect of chitosan and in vitro drug release behaviors were investigated. Pharmacokinetic and bioavailability aspects were also discussed. The results showed that the powerful dispersing effect of SNM and the blocking action due to the swelling of chitosan were the two main factors contributing to the sustained drug release behavior. The swelling effect of chitosan in an acidic environment together with the shrinking effect in a relatively alkaline environment allowed regulation of drug release behavior in simulated gastrointestinal fluid. An in vivo study showed that the bioavailability of CAR was improved 182% compared with that of the commercial capsule when SNM was used as the drug carrier. As for CAR-CTS-SNM, the T(max) of CAR was delayed by about 3.4 h and the bioavailability was slightly increased in comparison with the commercial capsule. We believe that SNM and CTS-SNM developed in this study will help increase the use of polymers and inorganic materials in pharmaceutical applications and stimulate the design of oral drug delivery systems for immediate or sustained release of poorly water-soluble drugs.

Effect of polymers on in-vitro performance of eplerenone sustained release matrix tablets

Objectives : The intention of the present study was to design and assess oral sustained drug delivery systems for Eplerenone, using Cellulose and natural polymers as release modifiers in the form of matrix tablets. Material and methods : Matrix tablets containing cellulose polymers like HPMC K4M, HPMC K15M, NaCMC and natural polymers like Guar Gum, Xanthan Gum, and Karaya Gum were prepared by wet granulation technique using PVP K60 as a tablet binder. Results : The optimized formulation (F1) contains 1: 0.70 ratio (D: HPMC K4M) and (F4) contains 1:1 ratio (D: Guar gum) respectively. The in-vitro release kinetic studies of prepared matrix tablets with both the polymers were studied. The kinetic treatment illustrate that the optimized formulation (F1 and F4) followed zero order kinetics with release exponent (n) 0.87. Drug content in the tablets and amount of drug released were estimated by reported HPLC method. The FT-IR and DSC studies did not show any interaction of drug with the excipients used in the formulation. Conclusion : The results clearly indicated that Eplerenone could be successfully prepared using an appropriate ratio of cellulose polymers like HPMC K4M, and natural gums like Guar gum in the form of matrix tablets

Dry Adsorbed Emulsions: An Oral Sustained Drug Delivery System

The oral sustained drug delivery system “dry adsorbed emulsion” was defined as an organized dispersion of hydrophilic and hydrophobic particles whose structure was initiated by the structure of a water‐in‐oil (W/O) emulsion. Sodium salicylate was dissolved in the aqueous phase of the primary W/O emulsion as an active drug. The aqueous phase of the W/O emulsion was absorbed by a hydrophilic silica and then a hydrophobic silica was added to the preparation to obtain a stable and solid pulverulent form. The physicochemical structure of a “dry adsorbed emulsion” was described and observed by electron microscopy. The effect of different oils, castor oil and a silicone oil, on the sustained drug release was studied at two different pH values, 1.2 and 7.4, to simulate the gastric and intestinal medium, respectively. The properties of these forms were retained for more than one year at room temperature storage.