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Supercritical fluid (SCF) technology has become an important tool of materials processing in the last two decades. Supercritical CO2 and H2O are extensively being used in the preparation of a great variety of nanomaterials. The greatest requirement in the application of nanomaterials is its size and morphology control, which determine the application potential of the nanoparticles, as their properties vary significantly with size. Although significance of SCF technology has been described earlier by various authors, the importance of this technology for the fabrication of inorganic and hybrid nanomaterials in biomedical applications has not been discussed thoroughly. This review presents the nanomaterial preparation systematically using SCF technology with reference to the processing of biomedical materials. The basic principles of each one of the processes have been described in detail giving their merits and perspectives. The actual experimental data and results have been discussed in detail with respect to the selected nanomaterials for biomedical applications. The SCF synthesis of nanoparticles like phosphors, magnetic materials, carbon nanotubes, etc. have been discussed as they have potential applications in bio-imaging, hyperthermia, cancer therapy, neutron capture therapy, targeted drug delivery systems and so on. The more recent approach towards the in situ surface modification, dispersibility, single nanocrystal formation, and morphology control of the nanoparticles has been discussed in detail.
K. ByrappabEmail:kbyrappa@gmail.com S. OharaaEmail:ohara@jwri.osaka-u.ac.jp T. AdschiriaEmail:ajiri@tagen.tohoku.ac.jp
[a]Institute of Multidisciplinary Research for Advanced Materials (IMRAM)Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan;[b]University of Mysore, P.B. No.21, Manasagangotri, Mysore 570 006, India
Endogenous Cushing’s syndrome is a relatively rare disease. Most cases being ACTH-dependent, ACTH-independent Cushing’s syndrome (AICS) is an even rarer condition [15%–20%]. In more than 95% cases the cause of AICS is unilateral adrenal enlargement caused by adenoma or carcinoma. Bilateral adrenal disease is caused by primary pigmented nodular adrenal dysplasia (PPNAD); ACTH-independent macro nodular hyperplasia (AIMAH). Only few case reports of the latter condition exist in the radiology literature, PPNAD being the commoner of two as the cause for AICS.
Ashish Verma1 Suyash Mohan1 Archna Gupta1 Email:agupta@sgpgi.ac.in
[1] Department of Radio Diagnosis, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Rae Bareily Road, Lucknow, 226 014, Uttar Pradesh, India
Endogenous Cushing’s syndrome is a relatively rare disease. Most cases being ACTH-dependent, ACTH-independent Cushing’s syndrome (AICS) is an even rarer condition [15%–20%]. In more than 95% cases the cause of AICS is unilateral adrenal enlargement caused by adenoma or carcinoma. Bilateral adrenal disease is caused by primary pigmented nodular adrenal dysplasia (PPNAD); ACTH-independent macro nodular hyperplasia (AIMAH). Only few case reports of the latter condition exist in the radiology literature, PPNAD being the commoner of two as the cause for AICS.
Ashish Verma1 Suyash Mohan1 Archna Gupta1 Email:agupta@sgpgi.ac.in
[1] Department of Radio Diagnosis, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Rae Bareily Road, Lucknow, 226 014, Uttar Pradesh, India
The purpose of this research was to design oral controlled release (CR) matrix tablets of zidovudine (AZT) using hydroxypropyl methylcellulose (HPMC), ethyl cellulose (EC); carbopol-971P (CP); to study the effect of various formulation factors on in vitro drug release. Release studies were carried out using USP type 1 apparatus in 900 ml of dissolution media. Release kinetics were analyzed using zero-order, Higuchi’s square root; Ritger–Peppas’ empirical equations. Release rate decreased with increase in polymer proportion; compression force. The release rate was lesser in formulations prepared using CP (20%) as compared to HPMC (20%) as compared to EC (20%). No significant difference was observed in the effect of pH of dissolution media on drug release from formulations prepared using HPMC or EC, but significant difference was observed in CP based formulations. Decrease in agitation speed from 100 to 50 rpm decreased release rate from HPMC; CP formulations but no significant difference was observed in EC formulations. Mechanism of release was found to be dependent predominantly on diffusion of drug through the matrix than polymer relaxation incase of HPMC; EC formulations, while polymer relaxation had a dominating influence on drug release than diffusion incase of CP formulations. Designed CR tablets with pH independent drug release characteristics; an initial release of 17–25% in first hour; extending the release up to 16–20 h, can overcome the disadvantages associated with conventional tablets of AZT.
Punna Rao Ravi1 Email:rpunnarao@bits-pilani.ac.in Udaya Kanth Kotreka1 Email:kotrekau@duq.edu Ranendra Narayan Saha1 Email:rnsaha@bits-pilani.ac.in
[1] Pharmacy Group, Birla Institute of Technology; Science, Pilani, Rajasthan, India
The objective of this study was to develop a multiunit sustained release dosage form of diltiazem using a natural polymer from a completely aqueous environment. Diltiazem was complexed with resin; the resinate-loaded carboxymethyl xanthan (RCMX) beads were prepared by interacting sodium carboxymethyl xanthan (SCMX), a derivatized xanthan gum, with Al[+3] ions. The beads were evaluated for drug entrapment efficiency (DEE); release characteristics in enzyme free simulated gastric fluid (SGF, HCl solution, pH 1.2); simulated intestinal fluid (SIF, USP phosphate buffer solution, pH 6.8). Increase in gelation time from 5 to 20 min; AlCl3 concentration from 1 to 3% decreased the DEE respectively from 95 to 79%; 88.5 to 84.6%. However, increase in gum concentration from 1.5 to 2.5% increased the DEE from 86.5 to 90.7%. The variation in DEE was related to displacement of drug from the resinate by the gel forming Al[+3] ions. While 75–82% drug was released in 2 h in SGF from various beads, 75 to 98% drug was released in 5 hour in SIF indicating the dependence of drug release on pH of dissolution media. Although the beads maintained their initial integrity throughout the dissolution process in both media, as evident from scanning electron microscopic studies, the faster release in SGF was accounted for higher swelling of the beads in SGF than in SIF. When release data (up to 60%) was fitted in power law expression, the drug release was found to be controlled by diffusion with simultaneous relaxation phenomena.
Somasree Ray1 Sabyasachi Maiti2 Biswanath Sa2Email:biswanathsa2003@yahoo.com
[1] Gupta College of Technological Sciences, Ashram More, Asansol-1, India ;[2] Centre for Advanced Research in Pharmaceutical Sciences, Department Of Pharmaceutical Technology, Jadavpur University, Kolkata, 700032, India ;[3] Division of Pharmaceutics, Department of Pharmaceutical Technology, Jadavpur University, Kolkata, 700032, India
The purpose of this research was to develop the hydrodynamically balanced delivery system of Clarithromycin (CLA) which, after oral administration should have the ability to prolong gastric residence time with the desired in vitro release profile for the localized action in the stomach, in the treatment of Helicobacter pylori (H.pylori) mediated peptic ulcer. By applying wet granulation technique floating tablets of Clarithromycin were prepared. The proportion of sodium bicarbonate was varied to get the least possible lag time, also the polymer part varied to get the desired release. In vivo radiographic studies were performed with Barium sulphate loaded formulation to justify the increased gastric residence time of the dosage form in the stomach, based on the floating principle. The formulation developed using 66.2% Clarithromycin, 12% HPMC K4M polymer, 8% sodium bicarbonate gave floating lag time less than 3 min with a floating time of 12 h,; an in vitro release profile very near to the desired release. X-ray studies showed the enhanced gastric residence time of the tablet to 220±30 min. The mechanism of release of Clarithromycin from the floating tablets is anomalous diffusion transport; follows zero order kinetics. In vivo radiographic studies suggest that the tablet has increased gastric residence time for the effective localized action of the antibiotic (Clarithromycin) in the treatment of H.pylori mediated peptic ulcer.
Muralidhar Nama1 Ch ra Sekhar Rao Gonugunta1 Prabhakar Reddy Veerareddy1Email:vpreddyindia@yahoo.com
[1] Pharmaceutics, St. Peter’s Institute of Pharmaceutical Sciences, Warangal, Andhra Pradesh, India ;[2] St. Peter’s Institute of Pharmaceutical Sciences, Vidya Nagar, Hanmakonda, A.P., 506001, India
In this study an attempt was made to prepare mucoadhesive microcapsules of gliclazide using various mucoadhesive polymers designed for oral controlled release. Gliclazide microcapsules were prepared using sodium alginate; mucoadhesive polymer such as sodium carboxymethyl cellulose (sodium CMC), carbopol 934P or hydroxy propylmethyl cellulose (HPMC) by orifice-ionic gelation method. The microcapsules were evaluated for surface morphology; particle shape by scanning electron microscope. Microcapsules were also evaluated for their microencapsulation efficiency, in vitro wash-off mucoadhesion test, in vitro drug release; in vivo study. The microcapsules were discrete, spherical; free flowing. The microencapsulation efficiency was in the range of 65–80%; microcapsules exhibited good mucoadhesive property in the in vitro wash off test. The percentage of microcapsules adhering to tissue at pH 7.4 after 6 h varied from 12–32%, whereas the percentage of microcapsules adhering to tissue at pH 1.2 after 6 h varied from 35–68%. The drug release was also found to be slow; extended for more than 16 h. In vivo testing of the mucoadhesive microcapsules in diabetic albino rats demonstrated significant antidiabetic effect of gliclazide. The hypoglycemic effect obtained by mucoadhesive microcapsules was for more than 16 h whereas gliclazide produced an antidiabetic effect for only 10 h suggesting that mucoadhesive microcapsules are a valuable system for the long term delivery of gliclazide.
S. K. Prajapati1 Purnima Tripathi1 Udhumansha Ubaidulla2 Vikas An 3 Email:vikas.pharmaceutics@gmail.com
[1] Department of Pharmaceutics, Institute of Pharmacy, Bundelkhand University, Jhansi, Uttar Pradesh, India ;[2] Research; Development, Reddy’s Laboratory, Hyderabad, Andhra Pradesh, India ;[3] Department of Pharmaceutics, Seth G.L. Bihani S.D. College of Technical Education, Sri Ganganagar, Rajasthan, India
The aim of the investigation was to prepare; characterize wheat germ agglutinin(WGA)-conjugated poly(d,l-lactic-co-glycolic) acid nanoparticles encapsulating mometasone furoate (MF) as a model drug; assess changes in its fate in terms of cellular interactions. MF loaded nanoparticles were prepared using emulsion–solvent evaporation technique. WGA-conjugation was done by carbodiimide coupling method. The nanoparticles were characterized for size, zeta potential, entrapment efficiency; in-vitro drug release. The intracellular uptake of nanoparticles, drug cellular levels,; anti-proliferative activity studies of wheat germ agglutinin-conjugated; unconjugated nanoparticles were assessed on alveolar epithelial (A549) cells to establish cellular interactions. Prepared nanoparticles were spherical with 10–15 μg/mg of WGA conjugated on nanoparticles. The size of nanoparticles increased after conjugation; drug entrapment; zeta potential reduced from 78±5.5% to 60±2.5%; 15.3±1.9 to 2.59±2.1 mV respectively after conjugation. From the cellular drug concentration–time plot, AUC was found to be 0.4745, 0.6791; 1.24 for MF, MF-nanoparticles; wheat germ agglutinin-MF-nanoparticles respectively. The in-vitro antiproliferative activity was improved; prolonged significantly after wheat germ agglutinin-conjugation. The results conclusively demonstrate improved availability; efficacy of antiasthmatic drug in alveolar epithelial cell lines. Hence, a drug once formulated as mucoadhesive nanoparticles; incorporated in dry powder inhaler formulation may be used for targeting any segment of lungs for more improved therapeutic response in other lung disorders as well.
Naazneen Surti1 Sachin Naik1 Tamishraha Bagchi2 B. S. Dwarkanath3 Ambikan an Misra1 Email:misraan@hotmail.com
[1] Pharmacy Department, Faculty of Technology; Engineering, Kalabhavan, The Maharaja Sayajirao University of Baroda, Vadodara, 390001 Gujarat, India ;[2] Department of Microbiology; Biotechnology Centre, Faculty of Science, The Maharaja Sayajirao University of Baroda, Sayajigunj, Vadodara, 390002, India ;[3] Institute of Nuclear Medicine; Allied Sciences, New Delhi, India
The purpose of the research was to evaluate Sterculia foetida gum as a hydrophilic matrix polymer for controlled release preparation. For evaluation as a matrix polymer; characterization of Sterculia foetida gum was done. Viscosity, pH, scanning electronmicrographs were determined. Different formulation aspects considered were: gum concentration (10–40%), particle size (75–420 μm); type of fillers; those for dissolution studies; pH,; stirring speed were considered. Tablets prepared with Sterculia foetida gum were compared with tablets prepared with Hydroxymethylcellulose K15M. The release rate profiles were evaluated through different kinetic equations: zero-order, first-order, Higuchi, Hixon-Crowell; Korsemeyer; Peppas models. The scanning electronmicrographs showed that the gum particles were somewhat triangular. The viscosity of 1% solution was found to be 950 centipoise; pH was in range of 4–5. Suitable matrix release profile could be obtained at 40% gum concentration. Higher sustained release profiles were obtained for Sterculia foetida gum particles in size range of 76–125 μm. Notable influences were obtained for type of fillers. Significant differences were also observed with rotational speed; dissolution media pH. The in vitro release profiles indicated that tablets prepared from Sterculia foetida gum had higher retarding capacity than tablets prepared with Hydroxymethylcellulose K15M prepared tablets. The differential scanning calorimetry results indicated that there are no interactions of Sterculia foetida gum with diltiazem hydrochloride. It was observed that release of the drug followed through surface erosion; anomalous diffusion. Thus, it could be concluded that Sterculia foetida gum could be used a controlled release matrix polymer.
Amit Ashok Chivate1Email:amitchivate@rediffmail.com Sushilkumar Sharatch ra Poddar1 Shajahan Abdul1 Gaurav Savant1
[1] Department of Pharmaceutics, Principal K. M. Kundnani College of Pharmacy, Cuffe Parade, Mumbai, 400005, India ;[2] 103, Indu Apt, Friends Colony, Bhandup ;[East], Mumbai, 400042, Maharashtra, India
The ability of self-emulsifying drug delivery systems (SEDDS) to improve solubility, dissolution rate; bioavailability of a poorly water-soluble calcium channel blocker, nimodipine (NM) was evaluated in the present investigation. Solubility of NM in various oils, surfactants; cosurfactants was determined. The influence of the ratio of oil to surfactant + cosurfactant, pH of aqueous phase on mean globule size of resulting emulsions was studied by means of photon correlation spectroscopy. The NM loaded SEDDS selected for the in vitro; in vivo studies exhibited globule size less than 180 nm. In vitro dissolution studies indicated that NM loaded SEDDS could release complete amount of NM irrespective of the pH of the dissolution media. Pharmacokinetics of NM suspension, NM oily solution, NM micellar solution; NM SEDDS were evaluated; compared in rabbits. Relative bioavailability of NM in SEDDS was significantly higher than all the other formulations. NM loaded SEDDS were subjected to various conditions of storage as per ICH guidelines for 3 months. NM SEDDS successfully withstood the stability testing.
Amit A. Kale1 V ana B. Patravale1 Email:vbpatravale@udct.org
[1] Department of Pharmaceutical Sciences; Technology, Institute of Chemical Technology, Matunga, Mumbai, 400019, India