Recent Trends in Floating Drug Delivery System

The main goal of an oral controlled drug delivery system is to maximise bioavailability, which should be predictable and repeatable, by administering medications over extended periods of time. Patients choose this approach for a number of reasons, including as affordability, ease of transportation, efficacy, perceived safety, and patient acceptability. The gastrointestinal system's variety results in several physiological limitations for oral delivery. Additionally, a number of variables alter along the gastrointestinal system, all of which affect how well drugs are absorbed. The most crucial factors are surface area, pH, commensal bacteria, gastrointestinal transit time, and enzyme activity. An ideal medication delivery system should have two basic characteristics: one, it should be a single dose for the duration of the therapy, and two, the active medicine should be delivered directly to the site of action. To provide drug delivery systems that, by releasing the medicine in a regulated and predictable way, may reduce side effects, dosage frequency, and changes in plasma drug concentration while remaining in the stomach for an extended amount of time and maintaining active plasma drug concentration. One of the special characteristics of the system is the gastroretentive drug delivery mechanism (GRDDS). New medication delivery techniques continue to spark interest even though oral controlled release dose forms are the most often manufactured. Drugs are rapidly removed from the systemic circulation due to their short half-life and ease of absorption from the GI tract. For these medications to have sufficient therapeutic effectiveness, frequent dosing is required.

Oral drug delivery is the most preferred and con venient option as the oral route provides maximum active surface area among all drug delivery system for administration of various drugs. The attractiveness of these dosage forms is due to awareness to toxicity and ineffectiveness of drugs when administere d by oral conventional method in the form of tablets and capsules. Usually conventional dosage form produces wide range of fluctuation in drug concentration in the bloodstream and tissues with consequent undesirable toxicity and poor efficiency. The mainte nance of concentration of drug in plasma within therapeutic index is very critical for effective treatment. These factors as well as factors such as repetitive dosing and unpredictable absorption lead to the concept of oral controlled release drug delivery systems. Controlled release drug delivery system works on many different mechanisms to control the release rate of drugs. Various mechanisms like osmotic pressure, matrix system, reservoir system, altered density system etc. have been utilized as formulat ion approaches. The present article contains brief review on various formulation approaches for controlled release drug delivery system.


 Oral delivery of drug is the most preferable drug delivery due to the ease of administration, patient compliance and flexibility in the formulations. In recent era various technologies have been made in research and development of oral controlled release drug delivery system to overcome various physiological difficulties such as variation in gastric retention and emptying time. Conventional oral dosage forms pose low bioavailability problems due to their rapid gastric transition from stomach, especially in case of drugs which are less soluble at alkaline pH of intestine and locally acting drugs in stomach get rapidly emptied. So, frequency of dose administration in such cases is increased. Gastro retentive drug delivery system (GRDDS) is facing many challenges which can be overcome by upcoming newly emerging approach, raft forming systems (RFS). The present study provides valuable information and highlights advances in this raft forming system. Different types of smart polymers used for their formulation have also been summarized. The current review focuses on the mechanism, formulation development and evaluation aspects of the raft forming systems and also highlights parameters which may lead to response variations in altered physiological conditions are discussed as well.

To calculate the fractal dimension values of felodipine osmotic pump tablets during drug dissolution and to characterize the mechanism of the controlled drug release kinetics through three-dimensional fractal data. Three-dimensional fractal values of volume (Df,volume ) and surface (Df,surface ) of the tablet core were calculated based on the box counting method. During the process of release of felodipine, both Df,volume and Df,surface were within the range of 2-3 and then changed markedly after a period of 3.0 h release, corresponding to extensive changes in entire shape, interior porous channels and surface structure of the tablet core. The curve of Df,volume mirrored that for tablet volume, however the curve of Df,surface was quite different from that of the surface area. Results showed that values of Df,surface correlated well with the drug release rate. Df,surface was found to be an efficient fractal parameter that could be used to characterize the complex changes to the tablet core that take place during drug release. The fractal dimension can be used as a quantitative indicator reflecting the drug release performance and be regarded as a key indicator for the quality control of oral controlled drug delivery systems.

Cellulose nanofiber (CNF) aerogels with favorable floatability and mucoadhesive properties prepared by the freeze-drying method have been introduced as new possible carriers for oral controlled drug delivery system. Bendamustine hydrochloride is considered as the model drug. Drug loading was carried out by the physical adsorption method, and optimization of drug-loaded formulation was done using central composite design. A very lightweight-aerogel-with-matrix system was produced with drug loading of 18.98%±1.57%. The produced aerogel was characterized for morphology, tensile strength, swelling tendency in media with different pH values, floating behavior, mucoadhesive detachment force and drug release profiles under different pH conditions. The results showed that the type of matrix was porous and woven with excellent mechanical properties. The drug release was assessed by dialysis, which was fitted with suitable mathematical models. Approximately 69.205%±2.5% of the drug was released in 24 hours in medium of pH 1.2, whereas ~78%±2.28% of drug was released in medium of pH 7.4, with floating behavior for ~7.5 hours. The results of in vivo study showed a 3.25-fold increase in bioavailability. Thus, we concluded that CNF aerogels offer a great possibility for a gastroretentive drug delivery system with improved bioavailability.

Thepurpose of writing this review on gastro retentive drug delivery systems was tocompile the recent literature with special focus on floating drug deliverysystems (FDDS) to achieve gastric retention. FDDS are of particular interestfor drugs that are locally active and have narrow absorption window in stomachor upper small intestine, unstable in the intestinal or colonic environment,and exhibit low solubility at high pH value. It is known that differences ingastric physiology (such as, gastric pH, motility) exhibit both intra as wellas inter subject variability demonstrating significant impact on gastricretention time and drug delivery behaviour.Thus, gastroretention helps toincrease the gastric residence time and improve absorption of drugs with narrowabsorption window. Â The recentdevelopments of FDDS including the pharmacokinetic and pharmacodynamic aspectsaffecting gastric retention, approaches to design single-unit and multiple-unit floating systems, advantages and limitations over the conventional drugdelivery systems, and their classification and formulation aspects are coveredin detail. This review also summarizes the studies to evaluate the performanceand application of floating systems, and applications of these systems. KeyWords: Floating matrix, gastrointestinal, gastro retentive, system, evaluation.

Introduction: After more than four decades of intense research, oral controlled drug delivery systems (DDSs) still represent a topic of major interest for pharmaceutical scientist and formulators. This can be explained in part by considering the economic value of oral DDSs whose market accounts for more than half of the overall drug delivery market. Polymeric systems based on drug–polymer non-covalent interaction represent a limited, but growing part of the field. Despite the large amount of literature and published reviews covering specific aspects, there is still need for a review of the relevant literature providing a general picture of the topic.Areas covered: The present review aims at presenting the latest findings in drug–polymer and interpolymer non-covalent interactions in oral controlled delivery while providing a specific perspective and a critical point of view, particularly on the tools and methods used for the study of these DDSs. Four main sections are considered: i) ionic interactions between drugs and polymers; ii) interpolymer complexes; iii) hydrogen bond; and iv) hydrophobic interactions.Expert opinion: The largest part of the scientific literature deals with systems based on drug–polymer ionic interactions while hydrogen bonding and hydrophobic interaction though, very promising, are more difficult to exploit, and therefore less studied. An accurate and exhaustive representation of the specific role of the chemical functions in establishing predictable interactions between drug and polymers is still required.

The purpose of writing this review on floating drug delivery systems attempts to compile the recent literature with special focus on various floating drug delivery systems approaches that have recently become leading methodologies in the field of site-specific orally administered controlled release drug delivery. In recent years scientific and technological advancements have been made in the research and development of controlled release oral drug delivery systems by overcoming physiological adversities like short gastric residence times and unpredictable gastric emptying times. So generally floating dosage systems form important technological drug delivery systems with gastric retentive behavior and offer several advantages in drug delivery. In this review current and recent development of floating drug delivery system is discussed

Floating drug delivery systems: an approach to oral controlled drug delivery via gastric retention

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

Oral controlled drug delivery systems represent the foremost widespread kind of sustained drug delivery systems for the plain blessings of oral route of drug administration. Such systems release the drug with constant or variable unleash rates. The oral controlled release systems show a typical pattern of drug unleash within which the drug concentration is maintained in the therapeutic window for a chronic amount of your time (sustained release), there by guaranteeing sustained therapeutic action. They are used as single dosage form. Present work involves preparation and analysis of sustained release beads of beads of Zolmitriptan Hydrochloride using Sodium alginate as natural polymer as well as Hydroxyl Propyl Methyl Cellulose K15, Chitosan Hydrochloride. The technique employed for preparation of beads of the drug is ionotropic gelation.

Structural Transformations During Swelling of Polycomplex Matrices Based on Countercharged (meth)acrylate Copolymers (EudragitR EPO/EudragitR L 100-55)

Sustained-release floating drug delivery systems (FDDSs) enable prolonged and continuous input of the drug to the upper parts of the gastrointestinal tract have been designed and fabricated using three dimensional printing (3DP) technology. A new strategy is proposed for the development of FDDSs. The design of FDDSs was based on the sustained release formulation, with low density and floating features in order to prolong the gastric retention time, with special surface textures and variations of drug distribution in the FDDSs for constant release profiles. The local variations of drug in the FDDSs were traced by methylene blue. To measure the floating force, a novel apparatus was developed. Duration of buoyancy and drug release profiles were determined in vitro. It was found that FDDSs were able to float on the dissolution medium 12h, which was the whole tests time periods, and free out the model drug metformin hydrochloride in a way of near zero-order kinetics. 3DP is able to offer possibility for developing FDDSs with complicated design features for providing long-time gastro-retention and desired drug release profiles.

The main aim of this study was to develop hydrogel based controlled drug delivery system of Saquinavir mesylate as hard gelatin capsule which are able to deliver the drug at prolonged rate. The hydrogel was prepared by crosslinking HPMC 15 cps and Carbopol 971P and then granules are developed using MCC as diluent. Drug excipient compatibility was studied by FT-IR. The prepared hydrogels formulation are evaluated for Swelling index. Drug release from hydrogel was performed by using Franz diffusion cell. The prepared granules are evaluated for pre formulation studies (Bulk density, Tapped density, Angle of repose). The Saquinavir hydrogel capsule are evaluated for weight variation, Drug content uniformity (95%), Disintegration time (11 mins). In-vitro drug release studies are conducted for 12hrs by using USP type I apparatus which is showing drug release of 98%. From the drug release kinetics, it can be determined that the saquinavir hydrogel capsules drug release mechanism follows both the zero-order and Higuchi models. For all metrics, the formulation SHCF4 has demonstrated the best performance in accordance with pharmacopoeia standards.

In recent years the novel technology of floating drug delivery system formulations are designed for the new drugs for oral targeted drug delivery. The drugs are delivered by conventional dosage forms are having very short residence time, but the drugs which are act in stomach are have more residence time. The floating drug delivery systems are of particular interest for drugs drugs that are locally active and narrow absorption window in stomach. System which are retained in the stomach for a longer period of time and there by improve the bioavailability of drugs. In this review the various advantages are given which are very important for controlled drug delivery system. Floating drug delivery system have a bulk density less than gastric fluids. When the system floats on gastric contents the drug is released slowly at the desire rate from system. The polymers are suitable for floating drug delivery system are covered in this review.