Gul Majid Khan

Studies on drug release kinetics from ibuprofen–carbomer hydrophilic matrix tablets: influence of co-excipients on release rate of the drug

Controlled-release (CR) matrix tablets of ibuprofen (IBF) and Carbopol(R) 934P, and blended mixture of Carbopol(R) 934P and 971P resins, at different drug to polymers ratios, were prepared by the direct compression method. The investigation focuses on the influence of the proportion of the matrix material, and several co-excipients (lactose, microcrystalline cellulose (MCC), and starch) on the mechanism and release rate of the drug from the tablets. In vitro drug release in pH 7.2 phosphate buffer solution appears to occur both by diffusion and a swelling-controlled mechanism, exhibiting either anomalous or Case II type transport. The release process could be described by plotting the fraction released versus time and fitting data to the simple exponential model: Mt/Minfinity=ktn. The release kinetics were modified when the blended mixtures of Carbopol(R) 934P and 971P resins were used as the matrix materials. In general, all of the co-excipients, used in this study, enhanced the release rate of IBF. However, lactose demonstrated slower and more linear release behavior as compared to microcrystalline cellulose or starch. The dissolution T50 and T90 values for the three co-excipients were in the order of lactose>microcrystalline cellulose>starch.

Formulation and in vitro evaluation of ibuprofen-Carbopol 974P-NF controlled release matrix tablets. III: Influence of co-excipients on release rate of the drug.

In order to assess the potential of carbopol 974P-NF as matrix material in hydrophilic matrix tablets containing a slightly water-soluble drug, ibuprofen (IBF), controlled release matrix tablets of ibuprofen and carbopol 974P-NF, at different drug to polymer ratios, were prepared by the direct compression method. The influence of the concentration of the matrix material (carbopol 974P) and several co-excipients (lactose, microcrystalline cellulose, and starch) on the release rate of the drug was investigated. An in vitro dissolution test in pH 7.2 phosphate buffer solution showed that drug release from all the formulations containing carbopol 974P was considerably prolonged in concentration-dependent manners. Increasing the amount of carbopol 974P in tablets resulted in a reduction in the drug release rate and a linearization of the drug release curve. When the influence of the co-excipients on the release of the drug was examined, all of the co-excipients used in this study enhanced the release rate of IBF. However, lactose demonstrated slower and more linear release behavior as compared in microcrystalline cellulose or starch. The dissolution T50 and T90 values for the three co-excipients were in the order of lactose > microcrystalline cellulose > starch.

Preparation, characterization, and dissolution studies of ibuprofen solid dispersions using polyethylene glycol (PEG), talc, and PEG-talc as dispersion carriers

Solid dispersions of ibuprofen (IBF) were prepared by solvent evaporation method using polyethylene glycol 10000 (PEG), talc, and PEG-talc as dispersion carriers. The drug-carrier(s) interactions in the solid state were investigated using scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and x-ray diffraction analysis. Interactions in the solution were studied by performing dissolution experiments. No important and well-defined chemical interaction was found between the ingredients. The increase in the IBF dissolution rate from the solid dispersions with the carriers used in this study could be attributed to several factors such as improved wettability, local solubilization, and drug particle size reduction.

Ibuprofen release kinetics from controlled-release tablets granulated with aqueous polymeric dispersion of ethylcellulose II: Influence of several parameters and coexcipients

The objective of this study was to investigate the mechanism of ibuprofen (IBF) release from tablets prepared by wet granulation method, using Surelease as a granulating agent. The influence of certain parameters such as the levels of Surelease solids content (SSC), pH of dissolution media, selected dissolution method, and agitation speed on the release profiles of IBF was investigated. The effect of partial replacement of lactose (primary excipient) by various coexcipients such as microcrystalline cellulose, starch, polyvinylpyrrolidone (PVP), sodium alginate, hydroxypropylmethylcellulose (HPMC), and sodium carboxymethyl cellulose (CMC-Na) was also studied. Tablets prepared with surelease as a granulating agent were non-disintegrating and exhibited prolonged release rates as compared to control tablets. The release of IBF from the tablets appears to occur either via water-filled pores or by diffusion through membrane, depending on the levels of SSC. At higher SSC levels pH independent release profiles for IBF were achieved. Dissolution method and agitation speed exhibited no significant effect on the release profiles. All the coexcipients studied enhanced the release rates, irrespective of whether the coexcipients were water-soluble or water-insoluble.

Preparation, characterization, and evaluation of physicochemical properties of different crystalline forms of ibuprofen.

Different crystal forms of ibuprofen (IBF) were prepared using methods such as cooling hot solution of the drug and precipitation of crystals from the drug solution. Scanning electron microscopy (SEM), differential scanning calorimetry (DSC), melting point, x-ray powder diffractometry, infrared absorption spectroscopy (IR), and in vitro dissolution rate and stability studies were conducted to investigate various characteristics of different crystalline forms of the drug. Methods of preparation and nature of the solvents used in this study were found to have greater roles in changing the physicochemical properties of IBF.

Drug Release Kinetics from Tablet Matrices Based Upon Ethylcellulose Ether-Derivatives: A Comparison Between Different Formulations

ABSTRACT The present study involved the preparation of ibuprofen-containing controlled release tablets formulated from either the established granular product, Ethocel®Standard Premium, or the novel finely-milled product, Ethocel®Standard FP Premium. The tablets were prepared by either direct compression or wet granulation. The aim was to explore the influence of different parameters on the kinetics and mechanisms of ibuprofen release from the tablets. These parameters were; polymer particle size, polymer molecular weight, drug : polymer ratio, preparation methodology and partial replacement of lactose with the coexcipient—hydroxypropyl methylcellulose (HPMC). The derived drug release data were analyzed with reference to various established mathematical models while the f2-metric technique was used in order to determine profile equivalency. It was found that drug release was mostly modulated by several interactive factors apparently exhibiting crosstalk. Nevertheless, it was possible to identify some simple rules. Incorporation of Ethocel® FP polymers and application of the wet granulation technique facilitated greater efficiency in controlling ibuprofen release behavior from the matrices. Furthermore, drug release profiles could be modulated by partial substitution of the primary excipient with HPMC. Polymer concentrations and particle sizes, rather than viscosity grade, were found to be decisive factors in controlling drug release rates.

Isatis tinctoria mediated synthesis of amphotericin B-bound silver nanoparticles with enhanced photoinduced antileishmanial activity: A novel green approach

After malaria, Leishmaniasis is the most prevalent infectious disease in terms of fatality and geographical distribution. The availability of a limited number of antileishmanial agents, emerging resistance to the available drugs, and the high cost of treatment complicate the treatment of leishmaniasis. To overcome these issues, critical research for new therapeutic agents with enhanced antileishmanial potential and low treatment cost is needed. In this contribution, we developed a green protocol to prepare biogenic silver nanoparticles (AgNPs) and amphotericin B-bound biogenic silver nanoparticles (AmB-AgNPs). Phytochemicals from the aqueous extract of Isatis tinctoria were used as reducing and capping agents to prepare silver nanoparticles. Amphotericin B was successfully adsorbed on the surface of biogenic silver nanoparticles. The prepared nanoparticles were characterized by various analytical techniques. UV-Visible spectroscopy was employed to detect the characteristic localized surface plasmon resonance peaks (LSPR) for the prepared nanoparticles. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) studies revealed the formation of spherical silver nanoparticles with an average particle size of 10-20nm. The cubic crystalline structure of the prepared nanoparticles was confirmed by X-ray diffraction (XRD) study. FTIR spectroscopic analysis revealed that plant polyphenolic compounds are mainly involved in metal reduction and capping. Under visible light irradiation, biogenic silver nanoparticles exhibited significant activity against Leishmania tropica with an IC50 value of 4.2μg/mL. The leishmanicidal activity of these nanoparticles was considerably enhanced by conjugation with amphotericin B (IC50=2.43μg/mL). In conclusion, the findings of this study reveal that adsorption of amphotericin B, an antileishmanial drug, to biogenic silver nanoparticles, could be a safe, more effective and economic alternative to the available antileishmanial strategies.

Photocatalytic and antibacterial response of biosynthesized gold nanoparticles.

Increase in the bacterial resistance to available antibiotics and water contamination by different toxic organic dyes are both severe problems throughout the world. To overcome these concerns, new methodologies including synthesis of nontoxic, human friendly and efficient nanoparticles is required. These nanoparticles not even inhibit the growth of microorganisms but are also effective in the degradation of toxic organics in waste water thus providing a clean and human friendly environment. The use of plants extracts to synthesize and stabilize noble metal nanoparticles have been considered as safe, cost-effective, eco-benign and green approach nowadays. In the present study, Longan fruit juice proficiently reduced ionic gold (Au(+3)) to gold nanoparticles (AuNPs) as well as mediated the stabilization of AuNPs. The antibacterial activity of AuNPs was carried out against both gram positive and gram negative bacteria using agar well diffusion method, followed by the determination of Minimum inhibitory concentration (MIC) values. AuNPs were found to have significant antibacterial activity against Escherichia coli with MIC values of 75μg/ml while outstanding MIC values of 50μg/ml against Staphylococcus areous and Basilus subtilus. AuNPs revealed significant photocatalytic degradation (76%) of methylene blue in time period of 55min, indicating the effective photocatalytic property of biosynthesized AuNPs (K=0.29/min, r(2)=0.95). The considerable antibacterial and photocatalytic activities of the photosynthesized AuNPs can be attributed towards their small size, spherical morphology and uniform dispersion. Our finding suggests the possible therapeutic potential of biogenic AuNPs in the development of new antibacterial agents as well as in the development of effective photocatalysts.

Biodirected synthesis of palladium nanoparticles using Phoenix dactylifera leaves extract and their size dependent biomedical and catalytic applications

The emerging microbial resistance and increased water pollution are of serious concern around the globe. In order to cope with these problems, new strategies are needed to develop less toxic and more effective nanomaterials that could arrest the microbial growth and eliminate unwanted organic pollutants from water samples. In the present contribution, we report the green synthesis of palladium nanoparticles using the aqueous extract of Phoenix dactylifera leaves. The appearance of a characteristic surface plasmon resonance peak at 278 nm confirmed the synthesis of palladium nanoparticles (UV-vis spectroscopy). The formation of the PdNPs was optimized at different temperatures (30 °C, 60 °C and 90 °C) and varying amounts of leaf extract (5 mL, 10 mL and 20 mL) in order to control their size, shape and dispersion. Average particle sizes of 13, 5, and 21 nm were observed by using the leaf concentrations of 5, 10, and 20 mL, respectively (HRTEM, DLS), with a fixed amount of PdCl2 (0.003 M) at 60 °C. The PdNPs synthesized under the optimized conditions (10 mL extract + 60 °C + 0.003 M PdCl2) were spherical in shape, small sized and uniformly distributed (HRTEM). The biologically synthesized nanoparticles were tested for their size dependent biomedical and catalytic applications. The PdNPs synthesized under optimized conditions exhibited strong catalytic activity with a complete reduction of 4-nitrophenol to 4-aminophenol in only 2 min. These nanoparticles were highly active in scavenging DPPH free radicals. The optimized palladium nanoparticles also exhibited strong antibacterial efficiency against Pseudomonas aeruginosa 26 (±0.8 mm). This high activity of PdNPs may be due to their small size, high dispersion and surface capping phytochemicals.

Nanotechnology: from In Vivo Imaging System to Controlled Drug Delivery

Science and technology have always been the vitals of human’s struggle, utilized exclusively for the development of novel tools and products, ranging from micro- to nanosize. Nanotechnology has gained significant attention due to its extensive applications in biomedicine, particularly related to bio imaging and drug delivery. Various nanodevices and nanomaterials have been developed for the diagnosis and treatment of different diseases. Herein, we have described two primary aspects of the nanomedicine, i.e., in vivo imaging and drug delivery, highlighting the recent advancements and future explorations. Tremendous advancements in the nanotechnology tools for the imaging, particularly of the cancer cells, have recently been observed. Nanoparticles offer a suitable medium to carryout molecular level modifications including the site-specific imaging and targeting. Invention of radionuclides, quantum dots, magnetic nanoparticles, and carbon nanotubes and use of gold nanoparticles in biosensors have revolutionized the field of imaging, resulting in easy understanding of the pathophysiology of disease, improved ability to diagnose and enhanced therapeutic delivery. This high specificity and selectivity of the nanomedicine is important, and thus, the recent advancements in this field need to be understood for a better today and a more prosperous future.