Topical drug delivery system can be defined as direct effects of formulation or drug containing medication to the skin to get localizing effect of drug or directly cure cutaneous disorders. Emulgels has to be used as a topical drug delivery system for hydrophobic drugs. When gels and emulsions are used in combined form the dosage forms are referred as emulgels. Emulgels have emerged as one of the most interesting topical delivery system as it has dual release control system i.e. gel and emulsion. The major objective behind this formulation is delivery of hydrophobic drugs to systemic circulation via skin. In recent years, there has been great interest in the use of novel polymers which can function as emulsifiers and thickeners because the gelling capacity of these compounds allows the formulation of stable emulsions and creams by decreasing surface and interfacial tension and at the same time increasing the viscosity of the aqueous phase. In fact, the presence of a gelling agent in the water phase converts a classical emulsion into an emulgel. Emulgels for dermatological use have several favourable properties such as being thixotropic, greaseless, easily spreadable, easily removable, and emollient, no staining, water-soluble, longer shelf life, and bio-friendly, transparent & pleasing appearance. These emulgels are having major advantages on novel vesicular systems as well as on conventional systems in various aspects. Various permeation enhancers can potentiate the effect. So emulgel formulations can be used as better topical drug delivery systems over present conventional systems available in market.
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Topical drug delivery system can be defined as direct effects of formulation or drug containing medication to the skin to get localizing effect of drug or directly cure cutaneous disorders. The skin has evolved to prevent excessive water loss from the internal organs and to limit the ability of xenobiotics and hazardous substances to enter the body. Notwithstanding this barrier function, a number of strategies have been developed by scientists to deliver drugs to and through the skin. Skin as an important site for topical effects so there is considerable interest in the skin for local and systemic effect of drug application. However, in the skin, the stratum corneum is the main barrier for drug penetration there by limiting topical and transdermal bioavailability. Skin penetration enhancement techniques have been developed to improve bioavailability and increase the range and number of drugs available for both topical and transdermal delivery. In this review, we have discussed about the various penetration enhancers, their mechanism of action and their potential for clinical application. Keywords: Topical Drug Delivery, Skin, Stratum Corneum Modification, Penetration Enhancers, Bioavailability.
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Abstract: The best strategy in the development of topical drug delivery systems may be to facilitate the permeation of drugs without any harmful effects, while staying on the skin sur- face and maintaining stability of the system. Nanodiamonds (NDs) play a key role with their excellent physicochemical properties, including high biocompatibility, physical adsorption, reactive oxygen species (ROS) scavenging capability, and photostabilizing activity. Z-average sizes of carboxylated ND (ND–COOH) agglutinate decreased significantly as the pH increased. Fluorescein-conjugated ND was observed only on the stratum corneum, and no sample diffused into the dermal layer even after 48 hours. Moreover, ND–COOH and ND–COOH/eugenol com- plex did not show significant toxic effects on murine macrophage cells. ND improved in vitro skin permeation 50% acting as a “drug reservoir” to maintain a high drug concentration in the donor chamber, which was supported by quartz crystal microbalance results. Moreover, ND–COOH could adsorb a drug amount equivalent to 80% of its own weight. A photostability study showed that ND–COOH increased the photostability ~47% with regard to rate constant of the eugenol itself. A significant decrease in ROS was observed in the ND–COOH and ND–COOH/eugenol complex compared with the negative control during intracellular ROS assay. Moreover, ROS and cupric reducing antioxidant capacity evaluation showed that ND–COOH had synergistic effects of antioxidation with eugenol. Therefore, ND–COOH could be used as an excellent topical drug delivery system with improved permeability, higher stability, and minimized safety issue.
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However, these approaches do not only have limited skin permeability, but also cause skin irritation as well. Stratum corneum (SC) is a main barrier of many compounds passing through the skin. Several approaches have been developed to weaken this skin barrier. One possibility for increasing the penetration of drugs and many cosmetic chemicals is the use of vesicular systems, such as liposomes and niosomes. The aims of this study were to develop liposome enriched Dexibuprofen liposomal hydrogels for topical delivery, perform in vitro release studies and in vivo permeation studies through mice/rat skin, and evaluate the efficacy of liposomal gels against inflammation induced rats. The purpose was to provide the delivery of the topical drug at a sustained rate across intact skin to improve bioavailability and inflammation control for longer period from liposomal gels.
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The aim of this study was to formulate and evaluate niosome of octopirox. From the result obtained from executed experiment it can be conclude that.The drug and excipients were evaluated for confirmation. The entrapment efficiency results help to conclude that the V-16 batch having higher entrapment efficiency. The optimized batch also showed better drug entrapment. When niosomal cream evaluate for spreadability, pH, shown well consistency. When evaluated for the drug release of the optimized batch i.e. V-32 using o/w cream base, it was concluded that the drug release rate increases with its increasing concentration. The niosomal cream was evaluated for stability study; it was found there was no significant change in pH and Drug content.
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6. Future prospective: During formulation & development of any new formulation the most common problems faced from hydrophobic behavior of drugs which leads to poor water solubility and bioavailability problems. Because of hydrophobic nature of many drugs delivery of these to the biological system have be challenging. Creams, ointments and lotion are of different types of drug delivery system which has been applied topically have excellent emollient properties but retards the release of drugs due to presence of oleaginous bases. As compared to other topical systems gel provides quicker release of drug because gel provides aqueous environment to drugs. Hydrophobic drug can be incorporated in oily base and delivered to skin by using emulgel. All such points of interest of Emulgel over other topical drug delivery systems make them more effective and profitable. In future these properties will be utilized to convey more number of topical medications as Emulgel.
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In quasi emulsion solvent diffusion method affinity between good solvent and drug is stronger than the affinity between good solvent and poor solvent. Drug solution in the good solvent formed emulsion droplets (quasi) upon pouring into the poor solvent and the organic phase then diffused out in to the external phase resulting in the formation of pores in the micron-sized particles, known as microsponges that have taken a spherical shape due to constant stirring.
Nanomiemgel through an innovative formulation technique that uses the ―Multi Absorption Mechanism‖ concept and has a broad applicability. Nanomiemgel consists of two different matrices; 1 and 2. Matrix 1 contains the nano-emulsion and matrix 2 is comprised of the nano-micelles. The theory of the present study is that every nano drug delivery system is distinct and its rate and mechanism of absorption depend on the size, charge and composition of the nano drug delivery system. So, when a combination of completely different drug delivery systems is utilized for the delivery of a drug, the absorption of the combined system would be better than either of the individual drug delivery systems due to the usage of the maximum possible paths of absorption accessible for that particular drug.
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Rita et al. prepared modified proniosomal gel of hydroxyzine hydrochloride with coacervation phase separation technique by screening with various non-ionic surfactants, along with phospholipids. Further the formula variables were optimized with taguchi statistical method. In vitro release study specified that formula with ratio 1:1 of surfactant:cholesterol showed prolonged release furthermore, the interaction of phospholipids with skin lipids retained drug molecule giving a sustained presence at the receptor site and achieve localized action. Similarly, ex vivo permeation study was performed with male Wistar rat’s skin, a formulation containing surfactant:cholesterol in the ratio of 1:1 significantly resulted in intact lipid layer and retard drug release and also enhanced the fluidity of the membrane. There was no sign of erythema and edema when tested on rabbit skin also optimized formula retained its stability for 3 months period and concluded refrigeration temperature optimum for storage with least leakage . A transdermal proniosomal gel for Ketorolac was finished by Farooqui et al. from enhanced proniosomal suspension. Ketorolac by transdermal conveyance issues may emerge this can be limited by exemplification it with the new medication transporter. The proniosomes were set up by handshaking technique by dissolving cholesterol and surfactant in liquor; drug was broken up in phosphate cushion saline (PBS) pH 7.4. The PN suspension was kept refrigerated at 4°C. Carbopol 940 was utilized as a gelling specialist, and dimethylsulfoxide was utilized as entrance improving operator. The consolidation of proniosomal vesicles into the gel base decreased the in vitro medicates discharge from 94.05%. The rate restraint of carrageenan-initiated paw edema 5 h in the wake of applying the positive control was observed to be 60.00%; the LCI-1-a gel was observed to be 63.44% while LCI-1-b and LCE-d gel indicated 57.44% and 49.08%. The LCI-1-a demonstrated promising skin saturation potential, better solidness, and higher ensnarement proficiency than LCI-1-b and LCB-1-g detailing. LCI-1-a demonstrated high medication discharge (94.048%) more than 17 h after topical use of upgraded PN plan when contrasted with LCI-1-b, LCB-1-g, and marketed formulation which recommends that PN definition (LCI-1-an) is far way better method of organization of KT through the fundamental dissemination .
For the treatment of local as well as systemic skin disorders, topical drug delivery systems have been used for centuries offering the advantage of delivering the drug directly to the site of action and also delivering the drug for extended period of time at the affected area. When gel and emulsion are used in combined form the dosage form are referred as Emulgel. Since they contain dual control release systems: a gel and an emulsion, emulgels have emerged as one of the most interesting topical delivery system. They are emulsions of either oil-in-water or water in oil type, which are gelled by mixing with a gelling agent. The major objective behind emulgel is delivery of hydrophobic drugs via skin. Thus emulgels have major advantages on novel vesicular system as well as on conventional systems in various aspects. They are referred for topical use due to their favorable properties such as being greaseless, non-staining, thixotropic, emollient, easily removable, water soluble, bio-friendly, long shelf-life, transparent and pleasant appearance. The use of emulgels can be expanded in different classification namely analgesics, anti-inflammatory, anti-fungal, antiacne drugs and various cosmetic formulations.
Niosomes can be used to deliver both hydrophobic and hydrophilic drugs via transdermal route. Although niosomes were tried for various routes it is used in the market for transdermal route (Novasome Products Such as 30% Petrolatum Novasomes and 10% Salicyclic Acid Novasomes). Studies showed that an enhanced delivery of drugs when encapsulated in niosomes. Niosomes increase skin penetration of drugs and it can act as local depot for sustained release of dermally active compounds. When non ionic surfactants are incorporated into niosomes they are much better tolerated by the skin then when they are used in emulsion.
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Over the year it has showed promising result in comparison to oral drug delivery system as it eliminates gastrointestinal interferences and first pass metabolism of the drug but the main drawback of TDDS is it encounters the barrier properties of the Stratum Corneum i.e. only the lipophilic drugs having molecular weight < 500 Da can pass through it. So now a days, liposomes, niosomes, transferosomes and ethosomes are used to increase the permeability of drug through stratum corneum. Ethosomes have been found to be much more efficient in delivering drug to the skin, than that of liposomes or hydro-alcoholic solution. Ethosomes are the non invasive drug delivery carriers that enable drugs to reach the deep skin layers finally delivering to the systemic circulation. For optimal skin delivery, drug should be efficiently entrapped within ethosomal vesicles. Ethosomal drug delivery system is a new state of the art technique and easier to prepare in addition to safety and efficacy. Ethosomes have become a area of research interest, because of its enhanced skin permeation, improved drug delivery, increased
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Effective targeted drug delivery system has been a dream for a long time, but it has been largely frustrated by the complex chemistry that is involved in the development of new systems. Topical drug delivery system has many problems like poor permeability, skin irritation, allergic reactions etc. major problems of newly developed chemical entities is their poor solubility in water and pharmacokinetic issues. These poorly- water soluble drugs show many problems in formulating them in conventional dosage forms and the critical problems associated is its very low bioavailability. The invention of Nanosponge has become a significant step towards overcoming these problems. Nanosponge is tiny sponges with a size about a virus (250nm-1um), which can be filled with a wide variety of drugs. Nanosponge play vital role in targeting drugs delivery in a controlled manner. This sponge can circulate around the body until interact with specific target site and stick on surface and releasing drug in controlled manner both lipophilic and hydrophilic drugs are incorporated in nanosponge . Important characteristics of these sponges are their solubility in aqueous from and suitable for the drugs with poor solubility. This review is focusing on the preparation method, applications of nanosponge, factor in the field of drug delivery.
The drug delivery technology landscape has become highly competitive and rapidly evolving. More and more developments in delivery systems are being integrated to optimize the efficacy and cost-effectiveness of the therapy. Conventional topical formulations are intended to work on the surface of the skin. Normally, upon application such formulations release their active ingredients and producing a highly concentrated layer of active ingredient that is quickly absorbed. Therefore, need exists for a system to increase the amount of time that an active ingredient is present either on skin surface as well as within the epidermis, at the same time, minimizing its transdermal penetration in the body. In recent times, microsponge delivery system (MDS) has been successively addressed for the controlled release of drugs onto the epidermis with assurance that the drug remains chiefly localized and does not enter the systemic circulation in major amounts. Drug loaded microsponge consist of microporous beads, typically 10-25 μm in diameter that possess a versatility to entrap wide range of active agents. Microsponge Systems are based on microscopic, polymer-based microspheres that can suspend or entrap a wide variety of substances, and can then be incorporated into a formulated product such as a gel, cream, liquid or powder. Microsponge technology offers entrapment of ingredients and is believed to contribute towards reduced side effects, improved stability, increased elegance, and enhanced formulation flexibility. In addition, numerous studies have confirmed that microsponge systems are non-irritating, non- mutagenic, non-allergenic, and non-toxic. This review article covers methods of preparation, release mechanism, characterization and applications of microsponge delivery system with patent information and marketed formulations.
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To avoid the gastro intestinal side effects of the drug on chronic oral administration, to provide faster action, transdermal formulation of Aceclofenac entrapped in transfersomes was formulated and evaluated. The aim of the present study involves formulation and evaluation of transfersomes of Aceclofenac by thin film hydration technique to improve the solubility and permeability of the drug. Transferomes were prepared using phosphatidylcholine and three different surfactants (Span 20, Span 60 and Span 80) as bilayer forming components. Formulations were evaluated for different parameters like; physicochemical properties (optical microscopy, particle size distribution, zeta potential measurement, SEM), % entrapment efficiency, in vitro release and stability studies. The % entrapment efficiency of the formulations was found to be in the range of 52.96 % to 67.25 %. in vitro release studies constant release of drug for the period of 8 hrs and maximum release of drug was shown by formulation F2 (83.6%). The optimized transferomal dispersion was incorporated into gel base using Carbopol 934P and test results obtained were acceptable and transfersomes were found to be stable in gel base.
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Conventional topical formulations are intended to work on the superficial layers of the skin. Normally, upon application such products release their active ingredients producing a highly concentrated layer of active ingredient that is quickly absorbed. Thus, need exists for a system to increase the amount of time that an active ingredient may remain present either on skin surface as well as within the epidermis, at the same time minimizing its transdermal penetration in the body. Microsponge delivery system (MDS) fulfills all these requirements and controls the release of drugs onto the epidermis with an assurance that the drug remains localized on the skin surface or within the epidermis and does not enter the systemic circulation in major amounts. They also offer an advantage of programmable release and are biologically safe. Additionally, this technology
Microsponge delivery system is a unique and effective technology for the controlled release of topical agents. It is highly cross- linked porous, polymeric microspheres that can entrap wide range of active agents and in response to trigger or stimuli and release them onto the skin over a time. It consists of micro-porous beads, typically 5-300µm in diameter that acquire the flexibility to entrap a wide variety of active ingredients such as fragrances, sunscreens, emollients, anti-fungal, anti-infective, and anti-inflammatory agents etc., that are mostly used to prolong the topical administration of the drug . Recently it was investigated that microsponges also used for oral drug delivery system. The topical agent formulation with microsponge delivery system can be prepared in many different forms, such as cream, gel, or lotion. When the formulation is applied to the skin, the MDS releases its active ingredients on a time and in response to other stimuli (rubbing, temperature, pH etc.). They reduce side effects, enhance stability and modify drug release. Because of the size of the microsponges they cannot pass through the stratum corneum, so they remain on the skin surface and slowly releasing the active ingredients over a period. Slow rate of release from MDS reduce the irritancy associated with the topical agents. Slow and gradual release pattern of MDS prevents excessive build-up of the active agents in the
The structure of cubic mesophases is unique and comprises a curved bicontinuous lipid bilayer (with an estimated thickness of 3.5 nm) extending in three dimensions and two interpenetrating, but non-contacting, aqueous Nano-channels (with a fully swollen diameter of approximately 5 nm), with a high interfacial area of 400 m 2 /g (Drummond, CJ et al.,1999; Spicer, PT et al., 2005; Yaghmur, A et al., 2009). These mainly shows cubic mesophases prepared by unsaturated monoglycerides or phytantriol (PT) are the most frequently investigated liquid crystal structures for drug delivery (Amar-Yuli, I et al., 2009; Dong, YD et al., 2006; Dong, YD et al., 2008). The compartmentalization in cubic mesophases can be used to introduce guest drugs of hydrophilic, lipophilic or amphiphillic nature shown in figure 1. Hydrophilic drugs will be located close to the emulsifier polar head or in the water channels, whereas lipophilic drugs will be localized within the lipid bilayer and amphiphillic drugs in the interface (Sagalowicz, L et al., 2006). The bulk phase is commonly a clear, viscous, semi-solid gel in appearance and rheology to cross-linked polymer hydrogels (Spicer, PT et al., 2006). Its high viscosity makes it difficult to handle and limits its application and, furthermore, the bulk phase can cause the irritation reaction when in contact with the biological epithelia (Rosen, MR et al., 2006). To overcome these issues, an innovative strategy has been formulated to disperse the bulk phase into water in the form of small particles. The dispersed cubic particles are denoted as ‘cubosomes, which can stably exist in equilibrium with aqueous solution with the internal bicontinuous structure unchanged (Gustafsson, J et al.,1996). On the basis of polarized light microscopy and X-ray crystallographic studies, three distinct reversed bicontinuous cubic phases can be identified the double-diamond lattice, the body-centred cubic phase and the gyroid lattice (Larsson, K et al., 2000; Shah, JC et al., 2001).
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as ionic interaction, hydrogen bonding, or hydrophobic interaction. They do not change its polymeric structure even after being deformed for a very long time due to its elastic nature. Hydrogels are highly absorbent (can contain over 90% of water). Due to high water content, hydrogel swell up and it is able to give an improved sensitivity for skin in contrast to ointment and patches. Hydrogel are also well-known as intelligent gels or smart hydrogels. These gels have an ability to accept, transmit or process a stimulus, and react by showing a useful effect. They can recognize the existing stimulus and respond by showing alteration in their physical or chemical performance, consequential in the liberation of drug in a controlled manner.
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