pH triggered delivery of curcumin from Eudragit-coated chitosan microspheres for inflammatory bowel disease: characterization and pharmacodynamic evaluation.

OBJECTIVE: This investigation deals with the development and evaluation (in vitro and in vivo) of pH triggered Eudragit-coated chitosan microspheres of curcumin (CUR) for treating ulcerative colitis. METHODS: CUR-loaded chitosan microspheres were initially prepared by emulsion cross linking method followed by coating with Eudragit S-100. The pharmacodynamics of the developed formulation was analyzed in mice by acetic acid induced colitis model. RESULTS: The developed microspheres were of uniform spherical shape with high entrapment efficiency. CUR-chitosan microspheres showed less intense peaks compared to free CUR confirming inclusion of drug within microspheres as revealed by X-ray diffractogram. Uncoated CUR-chitosan microspheres exhibited burst release within initial 4 h while microspheres coated with Eudragit S-100 prevented premature release of CUR and showed controlled release up to 12 h following Higuchi model. In vivo organ biodistribution study showed negligible amount of CUR in stomach and small intestine confirming integrity of microsphere in upper gastrointestinal tract (GIT). In vivo study revealed significant reduction in severity and extent of colonic damage with CUR-loaded microspheres as compared to pure CUR which was further confirmed by histopathological study. CONCLUSION: In vitro and in vivo studies proved the developed formulations as a promising system for pH-dependent delivery of drug to colon in ulcerative colitis.

Curcumin-Zn(II) complex for enhanced solubility and stability: an approach for improved delivery and pharmacodynamic effects.

OBJECTIVE: The aim of present investigation was to prepare Curcumin-Zn(II) complex in a view to enhance solubility, stability and pharmacodynamic effect in experimentally induced ulcerative colitis. METHOD: Curcumin-Zn(II) complex was prepared by stirring curcumin with anhydrous zinc chloride at a molar ratio of 1:1. The prepared curcumin metallocomplex was characterized by TLC, FTIR, UV spectroscopy and (1)H NMR. In vitro kinetic degradation and solubility of Curcumin and Curcumin-Zn(II) complex was analyzed spectrophotometrically. Pharmacodynamic evaluation of curcumin and its metal complex was assessed in ulcerative colitis in mice. RESULTS: Curcumin showed chelation with zinc ion as confirmed by the TLC, FTIR, UV spectroscopy and (1)H NMR. The results of TLC [Rf value], IR Spectroscopy [shifting of stretching vibrations of υ(C=C) and υ(C=O)], UV spectra [deconvoluted with absorption band at 432-466.4 nm] of Curcumin-Zn(II) complex compared to curcumin confirmed the formation of metallocomplex. (1)HNMR spectra of Curcumin-Zn(II) showed the upfield shift of Ha and Hb. Kinetic stability studies showed metallocomplex with zinc exhibited good stability. In vivo study revealed significant reduction in severity and extent of colonic damage with Curcumin-Zn(II) which were further confirmed by histopathological study. CONCLUSION: This study recognizes higher solubility and stability of Curcumin-Zn(II) complex and suggested better pharmacodynamic effects.

Curcumin loaded microsponges for colon targeting in inflammatory bowel disease: fabrication, optimization, and in vitro and pharmacodynamic evaluation.

The present study was aimed to develop and optimize the microsponges of curcumin for colon specific drug delivery in a view to bypass the upper gastrointestinal tract (GIT) for enhanced therapeutic effect. Microsponges were developed by quasi emulsion solvent diffusion method using 3(2) full factorial design. Prepared microsponges were optimized in order to analyze the effects of independent variables (volume of ethanol and Eudragit L100) on the encapsulation efficiency, particle size, and drug release. The optimized formulation was subjected to in vivo study using acetic acid induced colitis model in rats. The F7 was selected as optimized formulation based on particle size of 41.63 µm, % entrapment efficiency of 78.13%, and % cumulative drug release of 84.12%, and desirability factor of 0.83. Release studies revealed that microsponges prevented the premature release of curcumin in upper GIT and specifically released the drug at colonic pH. The drug release profile of F7 formulation was subjected to different kinetic models and based upon the best correlation coefficient (r(2) = 0.9927) the release was found to follow Higuchi model, which suggested diffusion as the main mechanism of drug release. Pharmacodynamic study showed that curcumin loaded microsponges causes a significant decrease in edema, necrosis, and hemorrhage of colon as compared to free curcumin. This study proves that curcumin loaded microsponges may act as a promising drug delivery system for treatment of ulcerative colitis.

Development and optimization of osmotically controlled asymmetric membrane capsules for delivery of solid dispersion of lycopene.

The aim of the present investigation is to develop and statistically optimize the osmotically controlled asymmetric membrane capsules of solid dispersion of lycopene. Solid dispersions of lycopene with ß-cyclodextrin in different ratios were prepared using solvent evaporation method. Solubility studies showed that the solid dispersion with 1 : 5 (lycopene : ß-cyclodextrin) exhibited optimum solubility (56.25 mg/mL) for osmotic controlled delivery. Asymmetric membrane capsules (AMCs) were prepared on glass mold pins via dip coating method. Membrane characterization by scanning electron microscopy showed inner porous region and outer dense region. Central composite design response surface methodology was applied for the optimization of AMCs. The independent variables were ethyl cellulose (X1), glycerol (X2), and NaCl (X3) which were varied at different levels to analyze the effect on dependent variables (percentage of cumulative drug release (Y1) and correlation coefficient of drug release (Y2)). The effect of independent variables on the response was significantly influential. The F18 was selected as optimized formulation based on percentage of CDR (cumulative drug release) of 85.63% and correlation coefficient of 0.9994. The optimized formulation was subjected to analyze the effect of osmotic pressure and agitational intensity on percentage of CDR. The drug release was independent of agitational intensity but was dependent on osmotic pressure of dissolution medium.

Nanocarriers for diagnosis and targeting of breast cancer.

Breast cancer nanotherapeutics is consistently progressing and being used to remove the various limitations of conventional method available for the diagnosis and treatment of breast cancer. Nanoparticles provide an interdisciplinary area for research in imaging, diagnosis, and targeting of breast cancer. With advanced physicochemical properties and better bioavailability, they show prolonged blood circulation with efficient tumor targeting. Passive targeting mechanisms by using leaky vasculature, tumor microenvironment, or direct local application and active targeting approaches using receptor antibody, amplification in the ability of nanoparticles to target specific tumor can be achieved. Nanoparticles are able to reduce cytotoxic effect of the active anticancer drugs by increasing cancer cell targeting in comparison to conventional formulations. Various nanoparticles-based formulations are in the preclinical and clinical stages of development; among them, polymeric drug micelles, liposomes, dendrimer, carbon nanotubes, and nanorods are the most common. In this review, we have discussed the role of nanoparticles with respect to oncology, by particularly focusing on the breast cancer and various nanodelivery systems used for targeting action.

Curcumin: a boon to colonic diseases.

Curcumin, a natural polyphenolic compound present in turmeric, exhibited multiple pharmacological activities. Extensive studies in last two decade suggested that curcumin possesses anti-inflammatory, anticancer, antiviral, anti-amyloid, antiarthritic and antioxidant properties. The mechanism for these effects involves modulation of several signaling transduction pathways. Various clinical studies have suggested that curcumin might be a potential candidate for the prevention and/or treatment of a variety of colonic diseases such as ulcerative colitis, Crohn's disease and colonic cancer. However, several evidences suggested the role of curcumin in multiple diseases, but the major challenge is to obtain optimum therapeutic levels of curcumin due to its low solubility and poor bioavailability. Improved absorption and cellular uptake of curcumin can be achieved through alteration in formulation properties and novel approaches in delivery systems. This review presents an overview of the background of curcumin, pharmacology, pharmacokinetics, clinical evidence in chemoprevention of bowel diseases and recent approaches to deliver curcumin for improved cellular uptake and bioavailability.

Development of colon specific microspheres of flurbiprofen for inflammatory bowel disease.

In the present investigation chitosan microspheres loaded with flurbiprofen (FLB) were prepared by oil/oil emulsification method for colon specific drug delivery. FLB was entrapped in chitosan microspheres, following coating with Eudragit S-100 utilizing the benefits of pH dependent solubility of Eudragit S-100, so as to prevent the premature release of FLB in upper GIT. Different batches of FLB microspheres were prepared by varying FLB: chitosan ratio (1:1 to 1:4). The effect of chitosan concentration on size, entrapment efficiency, percent drug loading and degree of swelling was evaluated. DSC studies revealed the dispersion of FLB in the matrix of chitosan microspheres. SEM analysis indicated the nearly smooth surface and spherical shape of the prepared microspheres. X-ray diffract gram of FLB microspheres showed less intense peaks as compared to free FLB. In vitro release studies of uncoated FLB- chitosan microspheres showed burst release in initial 4 h, while Eudragit S-100 coated microspheres prevented the premature release of FLB and showed controlled release for 12 h following Higuchi model, thus suitable for colon specific drug delivery.

Gold nanoparticles: an era in bionanotechnology.

INTRODUCTION: Gold nanoparticles have been efficiently and effectively used for the delivery of biomolecules and genes along with the potential to offer extremely sensitive diagnostics and imaging methods. AREAS COVERED: This review discusses the historical aspects, synthesis of gold nanoparticles, gold nanoparticles as drug delivery vehicles, photothermal effect of gold nanoparticles and the applications of gold nanoparticles. Gold nanoparticles with their unique optical properties may be useful as biosensors in living cells and has application in the field of drug delivery and photothermal therapy. Depending on the size, shape and degree of aggregation and nature of the protecting organic shells on their surface, gold nanoparticles can appear red, blue and other colors and emit bright resonance light of various wavelengths, which falls under visible region. Because of this property, gold nanoparticles have been extensively used as probes for sensing/imaging a wide range of analysts/targets such as proteins, cells and nucleic acids. EXPERT OPINION: Gold nanoparticles provide an admirable platform for the delivery of biomolecules and genes.

An insight to osmotic drug delivery.

In a typical therapeutic regimen the drug dose and the dosing interval are optimized to maintain drug concentration within the therapeutic window, thus ensuring efficacy while minimizing toxic effects. For many decades treatment of acute disease or a chronic illness has been mostly accomplished by delivery of drugs to patients using various pharmaceutical dosage forms. The immediate release conventional dosage form does not provide the proper plasma concentration of drug for prolonged period. This results in the development of various controlled drug delivery system. Among which the osmotic drug delivery systems (ODDS) are gaining importance as these systems deliver the drug at specific time as per the path physiological need of the disease, resulting in improved patient therapeutic efficacy and compliance. They work on the principle of osmotic pressure for controlling the delivery of the drug. Osmotic drug delivery systems with their versatility and their highly predictable drug release rates offer various biomedical advantages when given parenterally like reduced dose, targeting of site, avoiding gastrointestinal stability, hepatic bypass of drug molecule and follows zero order kinetics. Osmosis is an aristocratic phenomenon that seizes the attention for its exploitation in zero-order drug delivery systems. The release of the drug is independent of pH and physiological factors of the GIT to a large extent. Optimizing semi-permeable membrane characteristics and osmotic agent can modulate delivery of drug from the system. This review highlights the theoretical concept of drug delivery, history, types of oral osmotic drug delivery systems, factors affecting the drug delivery system, advantages and disadvantages of this delivery system, theoretical aspects, applications, and the marketed status.

Meloxicam carbopol-based gels: characterization and evaluation.

PURPOSE: To formulate and evaluate the hydrogels containing meloxicam for topical application and also compare the effect of penetration enhancers on release of drug. METHODS: Meloxicam gels were prepared by dispersion method using carbopol-940 and 934 (1%w/w) as rate controlling polymer and drug penetration enhancers such as tween 80, oleic acid and sesame oil in the concentration of 1% and 2% . The formulated gels were evaluated for drug content, pH, viscosity, spreadability, extrudability, in vitro drug permeation, drug release kinetics, bioadhesion test, accelerated stability of selected gel formulation. The in vitro drug permeation through pig's skin was carried out by using Keshary-Chein diffusion cell and viscosity was determined by brookfield viscometer (Modle No. LVDVE). RESULTS: All the gel formulations were found to be very clear and homogeneous. Drug content of all formulations was found to be above 93%. Formulation F(14) containing carbopol-934(1%w/w) and sesame oil 2% gave 99% release as compared to other formulations obeying zero order kinetic with a good bioadhesion quality. The permeability coefficient of all formulations was found in the range of 0.2 to 0.4×10(-3)cm(2)/hr. The results were compared statistically and found with satisfactory correlation and it was observed that the rate of drug release increased with increase in concentration of penetration enhancers.