Colloidal Carrier Systems Research Articles

Modern topical drugs-new developments in galenics and pharmacology

The importance of topically applied pharmaceuticals, especially for the treatment of dermatological diseases, is still essential. Thanks to detailed knowledge of the organisation and function of the physicochemical barrier of the skin, new galenic concepts have increasingly been developed to market maturity in recent years. Colloidal drug carrier systems in particular, but also targeted physicochemical modifications of matrices are used to optimise the cutaneous bioavailability of topically applied drugs. In addition, new molecules are increasingly becoming available for the development of these preparations or drugs known from systemic therapy are being formulated into topicals. Against this background, dermatopharmacology is also developing more and more into ahighly specialised science in this area, which is producing innovative concepts for the therapy of special indications. In addition to the classic small-molecule drugs, biotechnological molecules are increasingly finding their way into application, so that amodern age of dermatopharmacology has dawned, which will open up previously unimagined possibilities for topical therapy now and in the coming years.

Physicochemical Stimuli-Mediated Precipitation Approach for the Modulation of Rifampicin's Dissolution and Oral Bioavailability.

The intricate process of protein binding orchestrates crucial drug interactions within the bloodstream, facilitating the formation of soluble complexes. This research endeavours to improve the dissolution and oral bioavailability of Rifampicin (RMP) by strategically manipulating drug-protein binding dynamics and the hydrophobic characteristics of human serum albumin (HSA). Various precipitation techniques leveraging methanol, ammonium sulfate, and heat treatment were meticulously employed to tailor the properties of colloidal albumin (HSA NPs). The resultant complexes underwent comprehensive characterization encompassing evaluations of hydrophobicity, size distribution, surface charge, and structural analyses through FTIR, TG-DSC, XRD, and morphological examinations. The findings revealed a significant binding affinity of 78.07 ± 6.6% with native albumin, aligning with prior research. Notably, the complex RMP-HSA NPs-M13, synthesized via the methanolic precipitation method, exhibited the most substantial complexation, achieving a remarkable 3.5-fold increase, followed by the ammonium sulfate (twofold) and heat treatment (1.07-fold) methods in comparison to native albumin binding. The gastric simulated media exhibited accelerated drug release kinetics, with maximal dissolution achieved within two hours, contrasting with the prolonged release observed under intestinal pH conditions. These findings translated into significant improvements in drug permeation, as evidenced by pharmacokinetic profiles demonstrating elevated Cmax, AUC, t1/2, and MRT values for RMP-HSA NPs-M13 compared to free RMP. In summary, this innovative approach underscores the potential of precipitation methods in engineering stable colloidal carrier systems tailored to enhance the oral bioavailability of poorly soluble drugs, offering a pragmatic and scalable alternative to conventional surfactants, polymers, or high-energy methods for complex formation and production.

Design Characterization and Stability studies of Mesalamine Loaded Solid Lipid Nanoparticles

Background: Solid lipid nanoparticles are a colloidal carrier system for topical, oral, and parenteral administration that are utilized to increase the bioavailability of mostly lipophilic medications. Mesalamine is an anti-inflammatory drug that works in inflammatory bowel disease and is structurally similar to salicylates. In the current study, glycerylmonostearate was used as a lipid, Tween 80 as a surfactant, and cremophor as a solubilizing agent to enhance the formulation, evaluation, and stability studies of mesalamine-loaded solid lipid nanoparticles. Results: Particle size, entrapment efficiency, scanning electron microscopy, and differential scanning calorimetry were used to characterize the formulations. The drug concentration in the MES-SLNs F-7 was found to be 334mg in a 100ml solution of SLNs, and the size of the MES-SLNs F-7 was 82.1±5.37nm. the zeta potential was -13.9mV, the polydispersity index was 0.35 0.15, and the formulated MES-SLNs showed burst release. The physical stability of the formulated MES-SLNs was determined by measuring the size of the MES-SLNs, and colour stored at four different temperatures (-20C, 40C, room temperature, and 400C) for three months. High Performance Liquid Chromatographic analysis was used to determine the MES-SLNs' chemical stability. At -20°C and 40°C, it was discovered that MES-SLNs were stable. Conclusion: The chemical stability of MES-SLNs was determined by HPLC analysis. It was found that MES-SLNs were stable at -20C and 40ºC.

Lipid Nanoparticles: An Effective Tool to Improve the Bioavailability of Nutraceuticals.

Nano-range bioactive colloidal carrier systems are envisaged to overcome the challenges associated with treatments of numerous diseases. Lipid nanoparticles (LNPs), one of the extensively investigated drug delivery systems, not only improve pharmacokinetic parameters, transportation, and chemical stability of encapsulated compounds but also provide efficient targeting and reduce the risk of toxicity. Over the last decades, nature-derived polyphenols, vitamins, antioxidants, dietary supplements, and herbs have received more attention due to their remarkable biological and pharmacological health and medical benefits. However, their poor aqueous solubility, compromised stability, insufficient absorption, and accelerated elimination impede research in the nutraceutical sector. Owing to the possibilities offered by various LNPs, their ability to accommodate both hydrophilic and hydrophobic molecules and the availability of various preparation methods suitable for sensitive molecules, loading natural fragile molecules into LNPs offers a promising solution. The primary objective of this work is to explore the synergy between nature and nanotechnology, encompassing a wide range of research aimed at encapsulating natural therapeutic molecules within LNPs.

Solid Lipid Nanoparticles: Peculiar Strategy to Deliver Bio-Proactive Molecules.

Novel Drug Delivery Systems (NDDS) provide numerous benefits compared to conventional dosage forms. Poor aqueous solubility, low bioavailability, frequent dosing, and particular hydrophilic lipophilic character of the drug are the biological factors associated with the traditional systems leading to the development of SLNs. For improving the solubility profile, enhancing the bioavailability, and attaining the best possible therapeutic effect of lipid inclined or aqueous inclined drug, formulating solid lipid nanoparticles is the best choice. Solid Lipid Nanoparticles (SLNs) have been projected as a colloidal carrier system with a size of 50-1,000 nm, collectively combining the benefits of other colloidal systems like liposomes, emulsions, etc., for delivering the drug at the target site. High absorption, high stability, and efficient drug packing enhance the pharmacokinetic and pharmacodynamic properties of the packed drug. Solid Lipid Nanoparticles can be developed in different dosage forms and administered via routes such as nasal, rectal, oral, topical, vaginal, ocular, and parenteral. They have higher physicochemical stability and the batch size can be easily scaled up at a low cost. Lipophilic as well as hydrophilic drugs can be easily incorporated into solid lipid nanoparticles. In this manuscript, the authors have reviewed different aspects of solid lipid nanoparticles, major principles behind mechanism methods, recent patents, applications, and therapeutic potentials of solid lipid nanoparticles.

Insights into soy Protein-Based drug delivery vehicles via molecular dynamic simulation

Protein-based drug carriers have emerged as promising candidates for efficient drug delivery among various colloidal carrier systems due to their low cytotoxicity, abundance, renewability, diverse functional groups and interactions, and high drug loading capacity. In this study, the molecular dynamics (MD) simulations are conducted to investigate the surface-governed mechanisms of soy protein as a drug delivery vehicle using allyl isothiocyanate (AITC) as the model drug. The interaction strengths between protein and AITCs are characterized, and the loading capacities of the protein molecules are calculated and compared with experimental results. Our findings reveal that both nonpolar and polar functional groups on the protein have the ability to adsorb AITCs, but the polar residues primarily facilitate stable attachment of the drug molecules through the electrostatic (dipole–dipole) interactions. Furthermore, tunable loading capability of soy protein drug carrier is observed by modifying its surface through two types of denaturation treatments: heat denaturation and breaking of disulfide bonds. Both denaturation approaches are found to increase the exposure of polar active sites, thereby enhancing the loading efficiency of the protein carriers. These findings contribute to the advancement and application of biodegradable protein-based drug carriers.

The role of polysaccharides in improving the functionality of zein coated nanocarriers: Implications for colloidal stability under environmental stresses

Zein has gained popularity over the past few years as an incredible food and bio-based materials. The potential functions and health benefits of zein microcapsules or micro-/nanoparticles in bioactive components delivery, structured emulsion, etc., have received great attention. However, the development has been limited by colloidal destabilization, especially when thermal processing is involved. There is a recent trend in developing zein-polysaccharide complexes (ZPCs), which has tremendously improved the performance of zein-based colloidal carrier systems or emulsions. Increasing our understanding of zein interactions and their contribution to the structure of various macromolecules can help us to develop novel biomaterials that can be used in food, agriculture, biomedicine, and cosmetics. In addition, these nanocarriers are suitable for the encapsulation and delivery of bioactive compounds which have positive perspective in food industry. Therefore, this article aimed to review recent advances in the ZPCs that can be applied to functional or health-promoting foods, with a focus on the characteristics of different ZPCs, factors and mechanisms affecting the stability (especially thermal stability) of these complexes, and their application in food industry as a carrier for BCs. Further, the stability of ZPCs based emulsions under processing and physiological environments, as well some typical effective methods are introduced. Also, the principal challenges and prospects were enumerated and discussed.

A review on the functions, preparation and future aspects of nanocapsules

The nano technology in medicinal field offers many exciting possibilities. Many techniques are being usedtoday. The application of many nanoparticles were developing and these involve the utilization of manufactured nanocapsules to form repairs at cellular level and it’s sometimes refers as nano medicine. Nanocapsules are submicroscopic colloidal drug carrier systems composed of an oily or an aqueous core surrounded by a thin polymer membrane. Two technologies can be used to obtain such nanocapsules: the interfacial polymerization of a monomer or the interfacial nanodeposition of a preformed polymer. In future the nanotechnology can creat many wonders in medical field. Nanotechnology is wonderfull technology that can used in diagnosis and treatment in medical field. This review was aimed to knowing the preparation, new aspects, and the applications of the nanocapsules.

Formulation development, optimization, and characterization of anti-fungal topical biopolymeric film using a niosomal approach

Background: Griseofulvin is an antifungal drug that is currently available in the market only in oral dosage forms. So, the development of topical treatment could be advantageous for the treatment of superficial fungal infections. Though for superficial fungal treatment, the skin acts as a major target as well as a principal barrier for drug delivery. To overcome this the colloidal carrier system niosome was used. Niosomes being in the nanometer size range would allow the delivery of the drug at the desired site. Niosomes being non-ionic surfactant-based vehicles would facilitate the passage of the drugs through as skin is composed of both lipid and aqua, which would create problems for any other delivery system. Methodology: Griseofulvin belonging to the BCS Class II was formulated in the form of niosomes to enhance the drug’s solubility. In this study, optimization of niosomal formulation was done using OVAT (one variable at a time) method. Here, the CMAs (critical material attributes) such as surfactant type, conc. of charge inducer and the ratio of surfactant: cholesterol and CPPs (critical processing parameters) such as rotational speed of evaporator flask, external phase temperature, hydration time, and external phase volume (both aqueous and organic), which are independent variables influencing factors at different levels. These are said to have a potential risk on the CQAs (critical quality attributes), which are dependent variables, such as vesicle size, vesicle shape, vesicle lamellarity, niosome aggregation, and drug entrapment efficiency, for the final selection of improved optimum batch. The films were prepared from the incorporation of griseofulvin-loaded optimized niosomes in chitosan film for topical drug delivery in superficial fungal infections. Characterization: The films properties were characterized by physical appearance, film thickness, weight variation, folding endurance, tensile strength, moisture, uptake, moisture content, drug content uniformity, In-vitro drug diffusion studies, ex-vivo studies, and antifungal efficacy against Candida albicans sp. Result and Discussion: Thus, chitosan film formulation integrating griseofulvin-loaded niosomes for topical delivery enhanced the solubility of the drug and avoided the side effects associated with the orally-administered marketed formulation. Conclusion: Biopolymer chitosan exhibited antifungal activity implying enhanced drug efficacy. Therefore, two concepts of using optimized vesicular carrier systems and biopolymeric films have been combined and this topical novel composite film having the potential for griseofulvin delivery to superficial fungal infections has been formulated.

Principles and Advantages of New Drug Delivery Technologie

Advanced drug delivery systems offer undeniable benefits for drug delivery. In the past three decades, new methods have been proposed to develop a novel carriers for drug delivery. Nowadays, the major goal is to maximize therapeutic benefit while minimizing side effects. Drug delivery technique is clearly shifting from the micro to nanoscale. Nano-drug delivery systems (NDDSs) are the most promising approach utilized to improve the accuracy of drug delivery and the efficacy of drugs.In this narrative review article, we evaluate how delivery challenges associated with commercial marketed products and discuss newer DDS is being carried out to overcome these challenges .Different colloidal carrier systems such as carbon nanotube ,liposome , were being studied and extensively investigated.

Dermal and Transdermal Macromolecule Delivery Using Enhancer Molecules and Colloidal Carrier Systems – Part 2: Percutaneous Administration of Heparin

Introduction: Heparin is a commonly used anti-coagulant administered either by intravenous or subcutaneous injection for a systemic effect or topically for the treatment of peripheral vascular disorders. Objective: This study aimed to formulate heparin in non-ionic colloidal carrier systems (CCSs) having enhanced percutaneous absorption for systemic and topical administration. Methods: Five CCSs were developed and characterized for their rheological properties, droplet size, and drug loading. The percutaneous absorption of heparin was evaluated in vitro using Franz diffusion cells with rats’ skin and with the aid of a developed high-pressure chromatography method. Furthermore, the efficacy of two developed heparin CCSs was tested percutaneously in rats by measuring the response against the time in comparison to subcutaneous administration. Results: The rheograms and droplet size measurements showed that the developed drug delivery systems have Newtonian properties with a droplet size between 109 and 460 nm. As much as 500 mg of heparin could be loaded in around 5 mL of CCS. Furthermore, using Franz diffusion cells, a diffusion rate of 19.216 ± 2.01 USP U/cm².h could be achieved for heparin-loaded CCSs. Moreover, the estimated percutaneous in vivo relative bioavailability in comparison to subcutaneous administration could reflect that at least more than 50% of the drug passed through the skin. Conclusion: The developed novel non-toxic CCSs containing heparin can be good candidates for percutaneous administration as alternative delivery systems for subcutaneous and intravenous invasive administration.

Rational Mitomycin Nanocarriers Based on Hydrophobically Functionalized Polyelectrolytes and Poly(lactide-co-glycolide).

Encapsulation of hydrophilic and amphiphilic drugs in appropriate colloidal carrier systems for sustained release is an emerging problem. In general, hydrophobic bioactive substances tend to accumulate in water-immiscible polymeric domains, and the release process is controlled by their low aqueous solubility and limited diffusion from the nanocarrier matrix. Conversely, hydrophilic/amphiphilic drugs are typically water-soluble and insoluble in numerous polymers. Therefore, a core–shell approach—nanocarriers comprising an internal core and external shell microenvironments of different properties—can be exploited for hydrophilic/amphiphilic drugs. To produce colloidally stable poly(lactic-co-glycolic) (PLGA) nanoparticles for mitomycin C (MMC) delivery and controlled release, a unique class of amphiphilic polymers—hydrophobically functionalized polyelectrolytes—were utilized as shell-forming materials, comprising both stabilization via electrostatic repulsive forces and anchoring to the core via hydrophobic interactions. Undoubtedly, the use of these polymeric building blocks for the core–shell approach contributes to the enhancement of the payload chemical stability and sustained release profiles. The studied nanoparticles were prepared via nanoprecipitation of the PLGA polymer and were dissolved in acetone as a good solvent and in an aqueous solution containing hydrophobically functionalized poly(4-styrenesulfonic-co-maleic acid) and poly(acrylic acid) of differing hydrophilic–lipophilic balance values. The type of the hydrophobically functionalized polyelectrolyte (HF-PE) was crucial for the chemical stability of the payload—derivatives of poly(acrylic acid) were found to cause very rapid degradation (hydrolysis) of MMC, in contrast to poly(4-styrenesulfonic-co-maleic acid). The present contribution allowed us to gain crucial information about novel colloidal nanocarrier systems for MMC delivery, especially in the fields of optimal HF-PE concentrations, appropriate core and shell building materials, and the colloidal and chemical stability of the system.

Novel naltrexone hydrochloride nanovaccine based on chitosan nanoparticles promotes induction of Th1 and Th17 immune responses resulting in protection against Toxoplasma gondii tachyzoites in a mouse model

This study was aimed to encapsulate and construct the Toxoplasma gondii surface antigen (SAG1) and naltrexone hydrochloride (NLT-HCL) as an adjuvant within chitosan nanoparticles (CS-NPs) to develop efficacious vaccine against T. gondii. Seven groups of BALB/c mice were immunized with SAG1, chitosan (CS), NLT-SAG1, CS-SAG1, CS-SAG1-NLT, CS-NLT and PBS. The efficiency of each approach was detected in vivo mouse immunization. Moreover, the immuno-induction effect of SAG1 recombinant protein and CS-NPs-based NLT-HCL as an adjuvant in a vaccine delivery was evaluated. Experimentally, Th1/Th17 biased cellular and humoral immune responses were activated in the mice immunized with CS-SAG1-NLT nanoparticles that were accompanied by considerable increased production of IFN-γ, IL-17, IL-12, IL-4, IFN-γ/IL-4 ratio, IgG, IgG2a. This group of mice also showed significantly increased survival time post-challenging. The successful encapsulated SAG1 recombinant protein and NLT-HCL, as an adjuvant, within CS-NPs can induce immune responses against toxoplasmosis. We could incorporate NLT-HCL adjuvant into the CS-NPs based delivery systems, which makes CS-NPs attractive as a colloidal carrier system for NLT-HCL as secondary adjuvant. This new approach or the simultaneous use of CS and NLT demonstrated that the co-administration of CS-NPs and NLT-HCL induce production of IL-17 cytokine. This approach can be used for vaccination purposes, in which Th17 and Th1 cellular immune are considered the key of the successful immune response.

Dermal and transdermal peptide delivery using enhancer molecules and colloidal carrier systems. Part V: Transdermal administration of insulin

In this study, insulin was loaded into non-ionic colloidal carrier systems (CCS) to be used as nano-sized drug delivery systems for transdermal administration. The CCS were characterized for their rheological properties, droplet size and drug loading. Also, the transdermal flux of insulin was estimated using Franz diffusion cells through the epidermis and all the layers of the rats’ skin. The efficacy of the administration of the CCS was assessed in vivo transdermally in rats. Based on the rheological properties and droplet size results, the formulated fluids were identified as nano-sized systems having an aqueous colloidal phase, where the hydrophilic peptide is located. Also, a flux of insulin as high as 0.119 ± 0.016 and 1.328 ± 0.047 iu/cm2.h through the rat’s skin and epidermis, respectively, could be achieved using CCSIn2. Moreover, the monitoring of the blood sugar level over 6.5 h after a single transdermal administration of CCS exhibited a slight decrease. However, a significant drop in the blood sugar level was observed when they were administered once every two days over 10 days. The developed insulin-loaded CCS containing the penetration enhancer DMSO are nano-sized drug delivery systems and can induce a delayed therapeutic effect by repeating the administration.

Formulation and Toxicity Evaluation of Nanostructured Lipid Carriers for the Treatment of Acne

Background: Acne vulgarise is an inflammatory disease involving the pathological alteration of the sebaceous glands of the body. It is not a life-threatening disease but has a great influence on lifestyle. Topical combination therapy of vitamin A and antibacterial drugs is an effective treatment for acne.
 Materials and Methods: The current work investigates the nanostructure lipid colloidal carrier system of Tretinoin and Clindamycin phosphate. Nanostructured lipid carriers (NLCs) were prepared by highspeed homogenization-sonication technique and characterized for physicochemical properties, permeation, in vivo anti-acne and toxicity (acute 2000 mg/Kg, repeat 1000 mg/kg) in Wistar rats. 
 Results: The prepared system was found to be stable, homogenous with more site retention of drugs having non-irritation and toxicity potential. The formulation showed a size of 283 nm, polydispersity index (PDI) 0.43 and Zeta potential (ZP) -37.9 mV with drug entrapment 92.0% and 66.15% for tretinoin and clindamycin respectively. Observed permeation was 18 % and 45% for Tretinoin and Clindamycin less than marketed formulation which is more focused on dermal retention of drug. No significant abnormalities and toxicological symptoms were observed for acute and repeat dose toxicity study for histopathology and haematological examinations of organs.
 Conclusion: Prepared NLC formulation was aimed at epidermal targeting. Based on obtained results it is concluded that developed lipid-based nanocarrier system of selected drugs showed the targeting potential for effective acne treatment.

Screening of Electrolyte Complexes Formed Between Dextran Sulfate and Amine Structures of Small-Molecule Drugs.

Formation of an electrolyte complex using the electrostatic interactions between a polyanionic polymer and a cationic drug is a simple and efficient method of preparing a colloidal drug carrier system. Dextran sulfate, with a negatively charged sulfate group, was reacted in an acetate buffer solution of pH 3 with positively charged 1° amine, 2° amine, 3° amine, piperazine, and piperidine structures from 24 small-molecule drugs. The electrolyte complex was formed from 15 drugs, 63% of those tested. The tendency to form the electrolyte complex was in the order of piperazine and piperidine >3° amine >>2° amine. The drugs with the 1° amine structure failed to form an electrolyte complex. The mean particle sizes were in the range of 50-740 nm, and most of them showed a submicron colloidal dispersion of <400 nm. Regarding drug encapsulation efficiency (%), 11 drugs with piperazine, piperidine, and 3° amine structures showed 60-98% efficiency, which was fairly high. The results suggest that directly forming the electrolyte complex with dextran sulfate yields promising structural attributes as a submicron colloidal drug carrier system.

Case studies of enhanced pharmacodynamic activity of poorly oral bioavailable drugs via solid lipid nanoparticles

Solid lipid nanoparticles (SLNs) considered as an alternative vehicle for the enhanced oral absorption of drugs, and also to enhance therapeutic effectiveness after oral administration. Pharmacodynamic activity of drug is mainly describes the pharmacological and therapeutic activity of drug to the biological system. Lipid nanoparticles especially SLNs made of physiological inert lipid molecules and helps the lymphatic transport. Numerous literatures is available on the effect of SLNs and other colloidal carrier systems on the pharmacokinetic activity of poorly bioavailable drugs, to improve their oral absorption and also respective mechanisms for the improved oral bioavailability. However, very few literatures is reported on the pharmacodynamic activity and the effect of dose on the pharmacodynamic activity. Therefore, the current review is mainly dealing with the effect of SLNs on the pharmacodynamic activity discussed. Keywords: Oral absorption, solid lipid nanoparticles, lymphatic transport, pharmacokinetics, pharmacodynamics.

Influence of Process Variables on Budesonide Nanoparticles Using Factorial Design

Aims: Nanoparticles are the colloidal carrier systems for delivery of poorly soluble drugs. Budesonide. (BUD) a corticosteroid practically insoluble in water is used in asthma treatment. The aim of the present research work was to develop and evaluate BUD nanoparticles.&#x0D; Methodology: The prepared formulation was analyzed for % encapsulation efficiency, particle size analysis, zeta potential, polydispersity index (PDI), scanning electron microscopy and transmission electron microscopy. Poloxamer-188 was found in stabilizing BUD nanoparticles.&#x0D; Results: The observed % encapsulation efficiency of the optimized batch was (82.95) %, particle size was 271.8 nm with PDI 0.456. Solvent injection method was successfully implemented to developed BUD nanoparticles poloxamer-188. Sonication time and amplitude played an important role in governing the particle size.&#x0D; Conclusion: It can be inferred from the study that nanoparticles are a potential drug delivery method for poorly water-soluble drug delivery which can not only get impacted by formulation variables but also by process variables.

A REVIEW ON PRONIOSOMES: A PRO-COLLOIDAL PARTICULATE DRUG CARRIER

Colloidal particulate carrier systems are the systems which carry particulates in a nanometre size. These systems are substantially effective for transportation and distribution of variety of loaded drugs to desired site and increase efficacy and decrease toxicity, to provide therapeutic activity in a controlled manner for a prolonged period of time. One such new emerging colloidal systems is proniosomes which has capacity to improve the bioavailability and also permeation of drugs across the stratum corneum to provide a controlled release action and reduce toxic effects associated with drugs. These are the dry formulations of water-soluble non-ionic surfactant coated carrier systems which immediately on hydration form niosomes. They have the capacity to overcome the various problems associated with niosomes and liposomes, like instability, transportation, distribution, storage and dosing. They offer versatile drug delivery concept for both hydrophilic and hydrophobic drugs. They have the capacity to deliver drugs effectively through different routes at specific site to achieve controlled release action. This review concentrates on preparation, characterization, components, structure, types, evaluation parameters, proniosomes in drug delivery and targeting, toxicities associated with proniosomes, proniosomes versus niosomes, clinical applications, mechanism of vesicle formation in proniosomes and future trends associated with it. Also, drug delivery via different routes, such as oral, parenteral, topical and transdermal, ocular, vaginal, mucosal, pulmonary and intranasal were discussed.

Solid lipid nanocarriers as alternative drug delivery system for improved oral delivery of drugs

Oral bioavailability of drugs is mainly limited due to the poor aqueous solubility, enhanced chemical degradation, reduced permeation and/or first pass metabolism. Various novel delivery systems are developed for improved oral bioavailability of these drugs such as modified orals, buccal, transdermal and osmotic delivery systems. Colloidal carrier systems such as nanoparticles, lipid nanoparticles, nanoemulsions, microspheres, liposomes, resealed erythrocytes and transfersomes were also developed to enhance the oral delivery. Among these, solid lipid nanocarriers (SLNs) also gain much attention on the enhancement of oral bioavailability. SLNs are submicron sized nanoparticles and composed of solid lipid, surfactants and cosurfactants. The enhanced oral bioavailability of poorly soluble drugs from SLNs might be due to the reduced particle size, bypassed presystemic metabolism, and enhanced gastric mucosa permeability. Vast literature is available for the advantages, limitations, preparation methods, evaluation parameters and application of SLNs in different routes. This review mainly focused on list of drugs developed as SLNs and considered as an alternative approach to enhance the oral bioavailability based on pharmacokinetic as well as pharmacodyanmic parameters was discussed.&#x0D; Keywords: Oral bioavailability, solubility, first-pass metabolism, solid lipid nanoparticles, pharmacokinetics, pharmacodynamics.