Asbestos Fiber Release Studies Using a Constructed Simulation Chamber

2021 ◽  
pp. 91-115
Author(s):  
Steven P. Compton ◽  
Matthew R. Underwood
Keyword(s):  
Asbestos Fiber ◽  
Release Studies ◽  
Simulation Chamber

Synthesis, Characterization and in-vitro drug release studies of a macromolecular prodrug of Didanosine.

2010 ◽  
Vol 2 (2) ◽  
Author(s):  
Neeraj Agrawal ◽  
M.J. Chandrasekar ◽  
U.V. Sara ◽  
Rohini A.
Keyword(s):  
Drug Release ◽  
Drug Level ◽  
Drug Release Profile ◽  
Sustained Drug Release ◽  
In Vitro Drug Release ◽  
Alkaline Environment ◽  
Stomach Acid ◽  
Release Studies ◽  
Macromolecular Prodrug

A macromolecular prodrug of didanosine (ddI) for oral administration was synthesized and evaluated for in-vitro drug release profile. Didanosine was first coupled to 2-hydroxy ethyl methacrylate (HEMA) through a succinic spacer to form HEMA-Suc-ddI monomeric conjugate which was subsequently polymerized to yield Poly(HEMA-Suc-ddI) conjugate. The structures of the synthesized compounds were characterized by FT-IR, Mass and 1H-NMR spectroscopy. The prodrug was subjected for in-vitro drug release studies in buffers of pH 1.2 and 7.4 mimicking the upper and lower GIT. The results showed that the drug release from the polymeric backbone takes place in a sustained manner over a period of 24 h and the amount of drug released was comparatively higher at pH 7.4 indicating that the drug release takes place predominantly at the alkaline environment of the lower GIT rather than at the acidic environment of the upper GIT. This pH dependent sustained drug release behavior of the prodrug may be capable of reducing the dose limiting toxicities by maintaining the plasma drug level within the therapeutic range and increasing t1/2 of ddI. Moreover, the bioavailability of the drug should be improved as the prodrug releases ddI predominantly in the alkaline environment which will reduce the degradation of ddI in the stomach acid.

Physicochemical Characterization of Solid Dispersions of Cefdinir with PVP K-30 and PEG 4000

2010 ◽  
Vol 3 (2) ◽  
pp. 948-956
Author(s):  
Kumar P ◽  
S Kumar ◽  
A Kumar ◽  
M Chander
Keyword(s):  
Solid Dispersions ◽  
Physicochemical Characterization ◽  
Drug Carriers ◽  
Dissolution Properties ◽  
Rate Of Dissolution ◽  
Peg 4000 ◽  
Release Studies ◽  
Crystalline Nature ◽  
Physical Mixtures

The purpose of this study was to prepare and characterize solid dispersions of the antibacterial agent Cefdinir with PEG 4000 and PVP K-30 with a view to improve its dissolution properties. Investigations of the properties of the dispersions were performed using release studies, X-ray powder diffraction (XRD) and Fourier transform infrared (FTIR). The results obtained showed that the rate of dissolution of Cefdinir was considerably improved when formulated in solid dispersions with PVP K-30 and PEG 4000 as compared with pure drug and physical mixtures. The results from XRD studies showed the transition of crystalline nature of drug to amorphous form, while FTIR studies demonstrated the absence of drug-carriers interaction.

Preparation and in vitro Evaluation of Bioadhesive Microparticulate System

1970 ◽  
Vol 1 (3) ◽  
pp. 257-266
Author(s):  
Nagda C. D. ◽  
Chotai N. P. ◽  
Patel S. B. ◽  
Soni T. J ◽  
Patel U. L
Keyword(s):  
Drug Loading ◽  
In Vitro Release ◽  
Phenyl Acetic Acid ◽  
Solvent Evaporation Method ◽  
Elimination Half ◽  
Release Studies ◽  
Differential Scanning Colorimetry ◽  
Polymer Interactions ◽  
Vitro Release

Aceclofenac (ACE) is NSAIDs of a phenyl acetic acid class. It is indicated in arthritis and osteoarthritis, rheumatoid arthritis, ankylosing spondylitis. It has short elimination half life of 4 hours. The objective of the study is to design, characterize and evaluate bioadhesive microspheres of ACE employing carbopol (CP) as bioadhesive polymer. Bioadhesive microspheres of ACE were prepared by solvent evaporation method. The prepared microspheres were free flowing and spherical in shape and characterized for drug loading, mucoadhesion test, infrared spectroscopy (IR), differential scanning colorimetry (DSC) and scanning electron microscopy (SEM). The in-vitro release studies were performed using pH 6.8 phosphate buffer. The drug loaded microspheres in a ratio of 1:5 showed 47% of drug entrapment; percentage mucoadhesion was 81% and 89% release in 10 h. The infrared spectra and DSC showed stable character of aceclofenac in the drug loaded microspheres and revealed the absence of drug-polymer interactions. SEM studies showed that the microspheres are spherical and porous in nature. The in vitro release profiles from microspheres of different polymer-drug ratios followed Higuchi model.

Synthesis of Calcium Carbonate Micro Particles using Emulsion Membrane Process Applied for Drug Release Studies

2017 ◽  
Vol 68 (10) ◽  
pp. 2320-2324
Author(s):  
Mariana Mateescu ◽  
Sanda Maria Doncea ◽  
Irina Chican ◽  
Cristina Lavinia Nistor ◽  
Ioneta Codrina Bujanca
Keyword(s):  
Light Scattering ◽  
Calcium Carbonate ◽  
Dynamic Light Scattering ◽  
Liquid Membranes ◽  
Membrane Process ◽  
Emulsion Method ◽  
Micro Particles ◽  
Release Studies ◽  
Emulsion Liquid Membranes ◽  
Span 80

The aim of this work is the synthesis of calcium carbonate (CaCO3) nano and microparticles and their application as biomaterials (vehicles) for the sustained release of doxycycline. CaCO3 micro particles were synthesized by water-in oil (W/O) emulsion method using emulsion liquid membranes with bis (2-ethylhexyl) phosphate (D2EHPA) as carrier, Span 80 as surfactant, and toluene and kerosene as organic solvents. The aqueous phases contained 1 M CaCl2, and 1 M Na2CO3, respectively. The Dynamic Light Scattering (DLS) data showed CaCO3 particles with sizes ranging from around 100 nm to 3500 nm. The CaCO3 particles with the average diameters around 600 nm attained an adsorbtion of doxycycline of maximum 97.9%, and a slow and steady release with a cumulative value of approximative 50% after ten days.

Gelatin and Glycerine-Based Bioadhesive Vaginal Hydrogel

2020 ◽  
Vol 17 (4) ◽  
pp. 303-311
Author(s):  
Roberta Cassano ◽  
Federica Curcio ◽  
Delia Mandracchia ◽  
Adriana Trapani ◽  
Sonia Trombino
Keyword(s):  
Differential Scanning Calorimetry ◽  
Inflammatory Process ◽  
Vaginal Mucosa ◽  
Vaginal Infection ◽  
Scanning Calorimetry ◽  
Time Intervals ◽  
Site Specific ◽  
Release Studies ◽  
Hiv Seropositive

Aim: The work’s aim was the preparation and characterization of a hydrogel based on gelatin and glycerine, useful for site-specific release of benzydamine, an anti-inflammatory drug, able to attenuate the inflammatory process typical of the vaginal infection. Objective: The obtained hydrogel has been characterized by Electronic Scanning Microscopy (SEM) and Differential Scanning Calorimetry (DSC). In addition, due to the precursor properties, the hydrogel exhibits a relevant mucoadhesive activity. Methods: The swelling degree was evaluated at two different pHs and at defined time intervals. In particular, phosphate buffers were used at pH 6.6, in order to mimic the typical conditions of infectious diseases at the vaginal level, particularly for HIV-seropositive pregnant women, and pH 4.6, to simulate the physiological environment. Results: The obtained results revealed that the hydrogel swells up well at both pHs. Conclusion: Release studies conducted at both pathological and physiological pHs have shown that benzydamine is released at the level of the vaginal mucosa in a slow and gradual manner. These data support the hypothesis of the hydrogel use for the site-specific release of benzydamine in the vaginal mucosa.

In Vitro Estimation of Photo-Protective Potential of Pomegranate Seed Oil and Development of a Nanoformulation

2019 ◽  
Vol 15 (1) ◽  
pp. 87-102 ◽  
Author(s):  
Surbhi Dhawan ◽  
Sanju Nanda
Keyword(s):  
Particle Size ◽  
Zeta Potential ◽  
Seed Oil ◽  
Topical Delivery ◽  
Inflammatory Activity ◽  
Pomegranate Seed Oil ◽  
Protective Potential ◽  
Release Studies ◽  
Pomegranate Seed

Background: Since ancient times, people have been using natural resources for photoprotection purposes. One such highly recognised natural agent is pomegranate seed oil, considered as wonder oil owing to the presence of several beneficial phytoconstituents. </P><P> Objective: The study aimed to establish the photoprotective potential of pomegranate seed oil through various in vitro and biochemical studies along with the formation of nanoemulsion, an efficient topical delivery system for the oil. </P><P> Method: Photo-protective potential of the oil was estimated by determining in vitro antioxidant and anti-inflammatory activity, total phenolic content, anti elastase, antihyaluronidase and anticollagenase activities of the oil. Ultrasonication method was used to formulate nanoemulsions. The optimisation was done following the central composite design. The characterisation was done by particle size analysis, zeta potential, polydispersity index, pH, viscosity, stability testing and transmission electron microscopy. The optimised nanoemulsion was loaded into a gel base for topical application and further release studies were carried out. </P><P> Results: The IC50 values of anti-elastase, anti-collagenase and anti-hyaluronidase were found to be 309 mg/ml, 4 mg/ml and 95 mg/ml respectively. The results of anti-oxidant and anti-inflammatory activity were also significant, which thereby established the photo-protective potential of the oil. The optimum batch 2 had particle size 83.90 nm, 0.237 PDI and -5.37 mV zeta potential. The morphology was confirmed by TEM. Batch 2 was incorporated into a gel base and release studies showed 74.12 % release within 7 hours. </P><P> Conclusion: Pomegranate seed oil possesses a potential photo-protective ability. Nanoemulsions proved to be a promising carrier for the topical delivery of the oil.

Asbestos Fiber Type and Length in Lungs of Chrysotile Textile and Production Workers: Fibers Longer than 18 μm

2000 ◽  
Vol 12 (sup3) ◽  
pp. 411-418 ◽  
Author(s):  
Bruce W. Case ◽  
André Dufresne ◽  
A.D. McDonald ◽  
J.C. McDonald ◽  
Patrick Sébastien
Keyword(s):  
Fiber Type ◽  
Asbestos Fiber
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