Indicators for lack of systemic availability of organic pigments

: Transfersomes are bilayer vesicles composed of phospholipid and edge-activators, which are mostly surfactant. Transfersomes based drug delivery system has gained a lot of interest of the pharmaceutical researchers for their ability to improve drug penetration and permeation through the skin. Transdermal drug delivery via transfersomes has the potential to overcome the challenge of low systemic availability. However, this complex vesicular system has different issues to consider for developing a successful transdermal delivery system. One of the major ingredients, phospholipid has versatile sources and variable effect on the vesicle size and drug entrapment in transfersomes. The other one termed as edge-activator or surfactant has some crucial consideration of skin damage and toxicity depending upon its type and concentration. A complex interaction between type and concentration of phospholipid and surfactant was observed, which affect the physicochemical properties of transfersomes. This review focuses on the practical factors related to these two major ingredients such as phospholipid and surfactant. The origin, purity, desired concentration, the susceptibility of degradation, etc. are the important factors for selecting phospholipid. Regarding surfactants, the major aspects are type and desired concentration. A successful development of transfersomes based drug delivery system depends on the proper considerations of these factors and practical aspects.

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DETERMINANTS OF SYSTEMIC AVAILABILITY OF MORPHINE AND BUPRENORPHINE IN THE RAT

Journal of Pharmacy and Pharmacology ◽

10.1111/j.2042-7158.1981.tb11697.x ◽

1981 ◽

Vol 33 (S1) ◽

pp. 38P-38P

Author(s):

M. Mistry ◽

J.B. Houston

Keyword(s):

Systemic Availability

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Disazo (Bishydrazone) pigments based on acetoacetanilides

Physical Sciences Reviews ◽

10.1515/psr-2020-0170 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Robert Christie ◽

Adrian Abel

Keyword(s):

Crystal Packing ◽

Molecular Geometry ◽

Coupling Reactions ◽

Dominant Group ◽

Color Strength ◽

Decomposition Products ◽

Organic Pigments ◽

Yellow Pigments ◽

Structure Investigations ◽

Coupling Components

Abstract Disazoacetoacetanilide pigments, more commonly known as diarylide yellows, are the most important group of yellow classical organic pigments. They were commercialized in the early 20th century many years after the introduction of the structurally related monazoacetoacetanilides (Hansa yellows). The molecules adopt the bis-ketohydrazone tautomeric form. X-ray single crystal structure investigations have provided an insight into the influence of the molecular geometry and crystal packing arrangements in the solid state on the properties of the pigments in application. The synthesis of diarylide pigments is relatively straightforward, the conditions essentially following those used for the corresponding monoazo pigments, so that the products are economically priced. In the case of these disazo pigments, suitable aromatic amines (1 mol) are bis-diazotized and the resulting bis-diazonium salts reacted with acetoacetanilide coupling components (2 mol), the two azo coupling reactions occurring at the same time. They are by far the dominant group of yellow pigments used in printing inks, well-suited for most standard process yellow inks. They were formerly important in the coloration of plastics but are no longer recommended for polymers processed above 200 °C, under which conditions toxic decomposition products are formed. Diarylide yellow pigments are characterized by high color strength, good to excellent solvent fastness, and good chemical stability, although they generally show inferior lightfastness.

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Perylene and perinone pigments

Physical Sciences Reviews ◽

10.1515/psr-2020-0190 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Robert Christie ◽

Adrian Abel

Keyword(s):

High Performance ◽

Heat Stability ◽

High Heat ◽

Structural Features ◽

Fastness Properties ◽

Tetracarboxylic Acid ◽

Organic Pigments ◽

Orange Color ◽

Cis Isomer ◽

Chemical Class

Abstract Perylenes and perinones are separate groups of pigments categorized within the carbonyl chemical class. The two pigment groups show similarities, for example, in their chemical structural features and, to an extent, in their technical and application properties as high-performance organic pigments. Perylenes constitute a series of firmly established high-performance pigments, offering red and violet colors, and also extending to black. Synthetically, they are derived from perylene-1,4,5,8-tetracarboxylic acid. The perylenes tend to be quite expensive pigments, but their high levels of fastness properties mean that they are suitable for highly demanding applications. In particular, they offer very high heat stability. Two perinone pigments are used commercially. In their synthesis from naphthalene-1,4,5,8-tetracarboxylic acid, they are formed as mixtures of the two isomers, which can be separated. The trans isomer, CI Pigment Orange 43, is a highly important commercial pigment, especially for plastics, while the cis isomer, CI Pigment Red 194, is bordeaux in color and is of much lesser importance. The perinone, CI Pigment Orange 43, provides a brilliant orange color and has very good fastness properties. Its commercial manufacture involves a challenging multistage procedure and consequently it is one of the most expensive organic pigments on the market.

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X-ray microscopy reveals the outstanding craftsmanship of Siberian Iron Age textile dyers

Scientific Reports ◽

10.1038/s41598-021-84747-z ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Andreas Späth ◽

Markus Meyer ◽

Thomas Huthwelker ◽

Camelia N. Borca ◽

Karl Meßlinger ◽

...

Keyword(s):

Iron Age ◽

Textile Production ◽

X Ray ◽

Organic Pigments ◽

Central Asian ◽

Metal Organic ◽

Pigment Distribution

AbstractThe excellent craftsmanship of ancient Oriental and Central Asian textile dyers is already demonstrated in the remarkable brilliance and fastness of the colours of the so-called Pazyryk carpet, the by far oldest pile carpet found to date. This specimen resembles the advanced craftsmanship of Iron Age Central Asian textile production. We have employed synchrotron-based µ-XRF imaging to detect the distribution of metal organic pigments within individual fibres of the Pazyryk carpet (about 2500 years old) and compare the results to wool fibres, which we prepared according to traditional Anatolian dyeing recipes. We observe congruent pigment distribution within specimens from the Pazyryk carpet and natural wool fibres that we have fermented prior to dyeing. Therefore, we conclude that the superior fermentation technique has been utilized about 2000 years earlier than known so far.

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Non-destructive analysis of organic pigments and dyes using Raman microprobe, microfluorometer or absorption microspectrophotometer

Studies in Conservation ◽

10.1179/sic.1989.34.1.38 ◽

1989 ◽

Vol 34 (1) ◽

pp. 38-44 ◽

Cited By ~ 12

Author(s):

Bernard Guineau

Keyword(s):

Organic Pigments ◽

Raman Microprobe ◽

Destructive Analysis ◽

Non Destructive

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Dioxazine pigments

Physical Sciences Reviews ◽

10.1515/psr-2020-0168 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Robert Christie ◽

Adrian Abel

Keyword(s):

High Performance ◽

Industrial Applications ◽

Textile Dye ◽

Linear Arrangement ◽

Natural Colorant ◽

X Ray ◽

Organic Pigments ◽

Tyrian Purple ◽

Violet Color ◽

The Individual

Abstract This chapter provides an overview of the structural and synthetic chemistry, and the industrial applications, of dioxazine pigments, a small group of high performance organic pigments. The color violet (or purple) has frequently assumed a prominent position in history, on account of its rarity and cost. The natural colorant Tyrian purple and the first synthetic textile dye, Mauveine, are prime examples of this unique historical feature. CI Pigment Violet 23, also referred to as Dioxazine Violet or Carbazole Violet, is one of the most universally used organic pigments, by far the most important industrial pigment in the violet shade area. Dioxazine Violet is also unique as the dominant industrial violet pigment providing a brilliant, intense violet color and an excellent all-round set of fastness properties. The pigment has a polycyclic molecular structure, originally described wrongly as a linear arrangement, and later shown to adopt an S-shaped arrangement on the basis of X-ray structural analysis. Two other dioxazine pigments are of rather lesser importance. The synthesis and manufacturing route to CI Pigment Violet 23 is described in the review. Finally, a survey of the principal current applications of the individual dioxazine pigments is presented.

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Discoloration of Historical Plastic Objects: New Insight into the Degradation of β-Naphthol Pigment Lakes

Polymers ◽

10.3390/polym13142278 ◽

2021 ◽

Vol 13 (14) ◽

pp. 2278

Author(s):

Anna Micheluz ◽

Eva Mariasole Angelin ◽

João Almeida Lopes ◽

Maria João Melo ◽

Marisa Pamplona

Keyword(s):

Light Exposure ◽

Molecular Structures ◽

Conservation Science ◽

Organic Pigment ◽

Organic Pigments ◽

Before And After ◽

The Individual ◽

Determining Factor ◽

Insight Into ◽

Historical Samples

Light is a determining factor in the discoloration of plastics, and photodegradation processes can affect the molecular structures of both the polymer and colorants. Limited studies focused on the discoloration of heritage plastics in conservation science. This work investigated the discoloration of red historical polyethylene (PE) objects colored with PR 48:2 and PR 53:1. High-density and low-density PE reference polymers, neat pigment powders, and historical samples were assessed before and after accelerated photoaging. The applied methodology provided insight into the individual light-susceptibility of polyethylenes, organic pigment lakes, and their combined effect in the photoaging of historical plastic formulations. After light exposure, both PE references and historical samples yellowed, PR53:1 faded, and PR 48:2 darkened; however, both organic pigments faded severely in the historical samples. This highlights the role played by the plastic binder likely facilitating the pigment photofading. Fourier transform infrared spectroscopy and mass spectrometry techniques—EGA-MS, PY-GC/MS, and TD-GC/MS—were successfully employed for characterizing the plastic formulations and degradation. The identification of phthalic compounds in both aged β-naphthol powders opens new venues for studies on their degradation. This work’s approach and analytical methods in studying the discoloration of historical plastics are novel, proving their efficacy, reliability, and potentiality.

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