AMORPHOUS PHARMACEUTICAL SOLIDS: A REVIEW

INDIAN DRUGS ◽  
2013 ◽  
Vol 50 (07) ◽  
pp. 5-13
Author(s):  
B. V Dhokchawle ◽  
◽  
S. J. Tauro ◽  
A. B Bhandari
Keyword(s):  
Freeze Drying ◽  
Amorphous State ◽  
Vapor Sorption ◽  
Pharmaceutical Solids ◽  
Preparation Methods ◽  
Continuous Increase ◽  
Amorphous Pharmaceuticals ◽  
Drug Molecules ◽  
Sorption Method ◽  
Quench Cooling

Amorphous pharmaceutical solids have recently attracted the interest of pharmaceutical scientists because of a continuous increase in the number of developmental drug molecules that are insoluble. Amorphous state of the drug provides several pharmacokinetic advantages over the crystalline state. In this review preparation methods, characterization techniques and applications of amorphous pharmaceuticals have been discussed. Quench cooling, melt extrusion, spray drying and freeze drying are important methods for amorphization of solids. Amorphous pharmaceutical solids are characterized by diffraction technique, spectroscopy, vapor sorption method and thermal analytical methods. Stability of amorphous solids is important as their advantage of improved solubility might not be long lasting.

An Overview of Nanoparticles: Current Scenario

2021 ◽  
pp. 239-246
Author(s):  
Seema U. Shinde ◽  
Nikita D. Gidde ◽  
Pradnya P. Shinde ◽  
Akshay B. Kadam
Keyword(s):  
Drug Delivery ◽  
High Stability ◽  
Hydrophobic Drug ◽  
Preparation Methods ◽  
Routes Of Administration ◽  
Drug Molecules ◽  
Conventional Drug ◽  
Current Scenario ◽  
Release Potential ◽  
Novel Drug

The simplest type of structures with sizes in the nm range will be nanoparticles. Any atom mean that is associated by intensity with other atoms within a 'limited' distance may be claimed to be a nanoparticle in principle. The creation of novel drug delivery systems using nanoparticles has seen an exponential interest in recent years. In terms of high stability, high precision, high drug carrying capability, managed release potential, the possibility of use in various routes of administration and the ability to deliver both hydrophilic and hydrophobic drug molecules, nanoparticles may offer significant advantages over conventional drug delivery. The emphasis of this study is on classification, types, synthesis, preparation methods, characterization, use, nanoparticle advantages, and health perspectives.

scholarly journals Nanosuspension Technologies for Delivery of Poorly Soluble Drugs

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Roya Yadollahi ◽  
Krasimir Vasilev ◽  
Spomenka Simovic
Keyword(s):  
Aqueous Solubility ◽  
Drug Formulation ◽  
Preparation Methods ◽  
Administration Routes ◽  
Drug Molecules ◽  
Advanced Therapies ◽  
Poorly Soluble ◽  
Minimal Damage ◽  
Processing Techniques ◽  
Cancer Tissues

Poor aqueous solubility of some drug molecules is a major problem in drug formulation. Drug nanosuspensions emerged as one solution to delivering such hydrophobic drugs. Scaling down to nanoparticles enhances drug aqueous solubility and bioavailability by increasing drug surface area that comes into contact with biological media. Nanosuspensions that have attracted particular attention are those sterically stabilised by steric polymers such as polyethylene glycol (PEG) with a typical size range of 10–100 nm. These nanoparticles are capable of accumulating in targeted areas such as cancer tissues and infarct zones with minimal damage to healthy tissues. Nanosuspensions are often prepared by commercially available methods such as high pressure homogenization, media milling, emulsification, and melt emulsification. Solidification and surface modification methods are post-processing techniques used to add particular properties for advanced therapies. In this review, we firstly describe preparation methods for nanosuspensions. Secondly, we highlight typical characterization techniques. Finally, we describe several practical application of applications for drug delivery design and different administration routes such as parenteral, pulmonary, oral, and ocular.

Organic vapor sorption method of isostructural solvates and polymorph of tenofovir disoproxil fumarate

2013 ◽  
Vol 50 (3-4) ◽  
pp. 253-262 ◽  
Author(s):  
Jangmi Lee ◽  
Stephan X.M. Boerrigter ◽  
Young Woo Jung ◽  
Youngjoo Byun ◽  
Soon Hong Yuk ◽  
...  
Keyword(s):  
Tenofovir Disoproxil Fumarate ◽  
Vapor Sorption ◽  
Organic Vapor ◽  
Sorption Method

A technique for preparing Beauveria spp. for scanning electron microscopy

1980 ◽  
Vol 58 (15) ◽  
pp. 1700-1703 ◽  
Author(s):  
E. C. Quattlebaum ◽  
G. R. Carner
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Freeze Drying ◽  
Osmium Tetroxide ◽  
Air Drying ◽  
Preparation Methods ◽  
Critical Point Drying ◽  
Scanning Electron

Vapor fixation for 96 h with 1% osmium tetroxide (OsO4) and 3–4 days air drying produced distortion-free specimens of Beauveria spp. for examination with the scanning electron microscope. A combination of 4 h OsO4 vapor fixation and freeze-drying also reduced disruption satisfactorily but specimens were not as well preserved as with the first method. Preparation methods that were ineffective in preventing collapse of hydrophilic structures were Cling Free® sprayed on specimens prior to examination, freeze-drying, critical-point drying (of unfixed material), and vapor fixation with glutaraldehyde.

Simple vapor sorption method for determination of water in liquids

1963 ◽  
Vol 29 ◽  
pp. 586-588 ◽  
Author(s):  
Sherril D. Christian ◽  
Harold E. Affsprung
Keyword(s):  
Vapor Sorption ◽  
Sorption Method

scholarly journals Technical note: Uncovering the influence of methodological variations on the extractability of iron-bound organic carbon

2021 ◽  
Vol 18 (11) ◽  
pp. 3409-3419
Author(s):  
Ben J. Fisher ◽  
Johan C. Faust ◽  
Oliver W. Moore ◽  
Caroline L. Peacock ◽  
Christian März
Keyword(s):  
Organic Carbon ◽  
Marine Sediments ◽  
Freeze Drying ◽  
Method Comparison ◽  
Technical Note ◽  
Synthetic Sample ◽  
Fixed Amount ◽  
Preparation Methods ◽  
Reactive Iron ◽  
Cbd Method

Abstract. Association of organic carbon (OC) with reactive iron (FeR) represents an important mechanism by which OC is protected against remineralisation in soils and marine sediments. Recent studies indicate that the molecular structure of organic compounds and/or the identity of associated FeR phases exert a control on the ability of an OC–FeR complex to be extracted by the citrate–bicarbonate–dithionite (CBD) method. However, many variations of the CBD extraction are used, and these are often uncalibrated to each other, rendering comparisons of OC–FeR values extracted via the different methods impossible. Here, we created synthetic ferrihydrite samples coprecipitated with simple organic structures and subjected these to modifications of the most common CBD method. We altered some of the method parameters (reagent concentration, time of the extraction and sample preparation methods) and measured FeR recovery to determine which (if any) modifications affected the release of FeR from the synthetic sample. We provide an assessment of the reducing capacity of Na dithionite in the CBD method (the amount of Fe reduced by a fixed amount of dithionite) and find that the concentration of dithionite deployed can limit OC–FeR extractability for sediments with a high FeR content. Additionally, we show that extending the length of any CBD extraction offers no benefit in removing FeR. Moreover, we demonstrate that for synthetic OC–FeR samples dominated by ferrihydrite, freeze-drying samples can significantly reduce OC–FeR extractability; this appears to be less of an issue for natural marine sediments where natural ageing mechanisms may mimic the freeze-drying process for more stable Fe phases. While our study is not an all-inclusive method comparison and is not aimed at delivering the “perfect” extraction setup, our findings provide a collected summary of critical factors which influence the efficiency of the CBD extraction for OC–FeR. As such, we provide a platform from which OC–FeR values obtained under different methods can be interpreted and future studies of sediment carbon cycling can build upon.

Mild Organic Base-Catalyzed Primary Alcohol-Selective Aroylation Reaction Using N-Aroylcarbazoles for Underexplored Prodrugs

2020 ◽  
Author(s):  
Yasuaki Morita ◽  
Bubwoong Kang ◽  
Rubi Nakashima ◽  
Yuki Shimizu ◽  
Asumi Sakai ◽  
...  
Keyword(s):  
Primary Alcohol ◽  
Reaction System ◽  
Organic Base ◽  
Base Catalyst ◽  
Preparation Methods ◽  
General Base ◽  
Drug Molecules ◽  
Synthetic Utility ◽  
Scale Preparation ◽  
Complex Drug

<div>We report a highly primary alcohol-selective aroylation reaction using N-aroylcarbazoles (NAroCs). The aroylation</div><div>proceeded smoothly in the presence of DBU, which most likely works as a general base catalyst in the reaction system. The synthetic utility was displayed in the primary alcohol-selective aroylation of complex drug molecules and natural products to their prodrugs. Stoichiometrically generated carbazole, the starting material of NAroCs could be easily recovered. We also established safer multigram and multidecagram scale preparation methods of NAroCs, which are easy-to-handle bench-stable reagents.</div>

scholarly journals Enhancing the aqueous solubility and dissolution of olanzapine using freeze-drying

2011 ◽  
Vol 47 (4) ◽  
pp. 743-749 ◽  
Author(s):  
Mudit Dixit ◽  
Ashwini Gopalkrishna Kini ◽  
Parthasarthi Keshavarao Kulkarni
Keyword(s):  
Dissolution Rate ◽  
Freeze Drying ◽  
Physical Stability ◽  
Amorphous State ◽  
Aqueous Solubility ◽  
Water Soluble ◽  
Freeze Dried ◽  
Poorly Water Soluble ◽  
Pure Drug ◽  
Stability Results

The aim of the present study was to develop an olanzapine freeze-dried tablet (FDT). The solubility and dissolution rate of poorly water-soluble olanzapine was improved by preparing a freeze-dried tablet of olanzapine using the freeze-drying technique . The FDT was prepared by dispersing the drug in an aqueous solution of highly water-soluble carrier materials consisting of gelatin, glycine, and sorbitol. The mixture was poured in to the pockets of blister packs and then was subjected to freezing and lyophilisation. The FDT was characterised by DSC, XRD and SEM and was evaluated for saturation solubility and dissolution. The samples were stored in a stability chamber to investigate their physical stability. Results obtained by DSC and X-ray were analysed and showed the crystalline state of olanzapine in FDT transformation to the amorphous state during the formation of FDT. Scanning electron microscope (SEM) results suggest reduction in olanzapine particle size. The solubility of olanzapine from the FDT was observed to be nearly four and a half times greater than the pure drug. Results obtained from dissolution studies showed that olanzapine FDT significantly improved the dissolution rate of the drug compared with the physical mixture (PM) and the pure drug. More than 90% of olanzapine in FDT dissolved within 5 minutes, compared to only 19.78% of olanzapine pure drug dissolved over the course of 60 minutes. In a stability test, the release profile of the FDT was unchanged, as compared to the freshly prepared FDT after 90 days of storing.

Sign in / Sign up

Export Citation Format

Share Document