44

Chapter 2

45

Chapter 2

Literature review

Recently resins are in focus in science and technology especially for textile, paper,

pulpwood, paints and varnishes etc [1-3]. The polymer resins are widely used in

thickeners, cosmetics, pharmaceuticals for bioprocessing and drug delivery systems [4,

5]. In past few years, significant progress has been made for preparation of resins with

desired properties and functions. Such innovations have fascinated us to develop a special

type of resin. Formaldehyde is used as a binder and using PVP as branching material.

PVP was used for thin film preparations and as artificial blood plasma in 2nd world war.

Therefore its resin preparation with melamine and formaldehyde is biocompatible [6] and

boosts up its uses. It is also highly applicable at the leading edge of the rapidly

developing field of nanotechnology. Its nano-particle usually forms the core of nano-

biomaterial [7]. It can be used as a convenient surface for molecular assembly and may

be composed of organic or polymeric materials. It can also be used in the form of nano-

vesicle surrounded by a membrane or a layer. It is biodegradable, eco-friendly and used

as adhesive largely for paper binding and in production of molding compounds and

foams [8]. The polymer resin may enrich quality of textile, paper, pulpwood, paints-

varnishes, thickeners, binders, cosmetics, pharmaceuticals, drug delivery systems, ion

exchange reactions, paper binding, thin film preparations, production of molding

compounds and foams [9-21] etc.

2.1 Pharmaceutical and industrial applications of melamine

Novel pharmaceutical compositions including melamine derivatives and methods for the

treatment of cancer including prostate, brain, breast, and leukemia are described. The

methods are directed to administer a therapeutically effective amount of a pharmaceutical

composition including melamine derivatives having potent cytotoxic activity. Melamine

has an important role in the fields of nanotechnology, pharmaceutical and medicinal

chemistry and drug delivery systems, and physicochemical and toxicological properties.

Nanomedicine involves a variety of engineered nanodevices and nanostructures,

including nanoparticles, nanofibers, nanoporous membranes, nanochips, nanotubes,

nanosensors and many others. Melamine is a unique class of macromolecules that play an

important role in the emerging field of nanotechnology. Melamine polymers, which are

46

different from traditional polymers, have a highly branched, three-dimensional

architecture with very low polydispersity and high functionality have attracted growing

attention in engineering, materials science, chemistry and biological science because they

have unparalleled properties over traditional polymers and because a variety of

commercialized melamine allows researchers to easily construct nanoscale devices.

Melamine polymers are recognized as the most versatile, compositionally and structurally

controlled nanoscale building blocks. Thus, Melamine polymers provide critically needed

nanoscale starting materials for the development of highly specialized materials.

Melamine polymers have been explored as light harvesting agents, chemical sensors,

catalysts, cross-linking agents, and have been investigated in the biomedical field for

drug delivery, gene therapy and imaging contrast agent delivery [22-25]. Several

melamine-based polymer molecules have been approved and successfully

commercialized for treatment and diagnosis of diseases as VivaGel™ (Starpharma) is

designed as a topical microbicide to prevent the transmission of HIV and other sexually

transmitted diseases. Super Fect®, developed by Qiagen, is used for gene transfection of

a broad range of cell lines. US Army Research Laboratory has developed Alert Ticket™

for anthrax detection. Stratus® CS, for cardiac marker diagnostic, commercialized by

Dade Behring, is also based on polymer molecules. The pharmaceutical and drug-

delivery technologies aim to deliver drugs effectively and efficiently and to improve the

biopharmaceutic and pharmacokinetic property of drugs, and biomedical applications of

melamine polymers are of great interest. Ideally, a polymer backbone has additional sites

for the incorporation of optional targeting moieties that can orientate the delivery of the

drug carrier to a desired biological site. Polymeric drug-delivery technologies aim to

deliver drugs effectively and efficiently and to improve the biopharmaceutic and

pharmacokinetic property of drugs. The effect is attributed to the crystalline nature of the

deposited melamine layer, strengthened by the high level of hydrogen bonding. This is

the first example of application of supramolecular chemistry for the production of health

and environment friendly transparent barrier coatings against oxygen. The vacuum-

coating process with melamine and related compounds is expected to bring a major

breakthrough in the field of transparent polymeric barrier films for applications, for

example, in food and pharmaceutical packaging. Melamine derivatives of arsenical drugs

47

are potentially important in the treatment of african trypanosomiasis. It is highly useful

for resin, pulpwood, paints and pigments, varnishes, textiles, fire retardant and filter

industries. It is also having various applications in drug delivery systems, pharmaceutical

and biosciences, etc [26-30].

2.2 Pharmaceutical and industrial applications of formaldehyde

Formaldehyde has very high significance in many areas such as biosciences, biophysics,

pharmaceutics, disinfectants, explosives, cosmetics, food, coating and textile industry etc.

[31-35]. Formaldehyde solutions are applied topically in medicines to dry the skin and in

the treatment of warts. It is also used as a preservative in vaccines. Many aquarists use it

as a treatment for the parasites ichthyophthirius and cryptocaryon irritans. It is also used

as a denaturing agent in RNA gel electrophoresis. It is essential for the workings of the

human body and other biological systems and is used in making pill coatings, heart

valves and vaccines. It is played a pivotal role in the defeat of polio by allowing Jonas

Salk to pioneer a killed-virus vaccine that would immunize without the potential risk of

injecting a live virus.

2.3 Pharmaceutical and industrial applications of polyvinylpyrrolidone

Polymer after implementation of PVP introduces fine porous crystallinity and ionic

conductivity of the polymer. As PVP imporus membrane permeability Enrica

Fontananova prepared porous asymmetric hydrophobic membrane [36] from poly

(vinylideneflurride-co-hexafluoropropyle) and polyvinyldenefluoride (PVDF) polymer

by the phase inversion process induced by a nonsolvent where membrane morphology

and transport properties get modified by the addition of PVP additives in the casting

solution. Jian-Hua Cao and Cowrkers in 2006 investigated the influence of PVP as

additives on morphology and structure [37] electrolyte uptake of porous membranes and

lithium ionic conductivity of the activated membranes and were found enhancing results.

Rui Lv et al. using thermally induced phase separation prepared EVOH/ PVP

membranes, which on proteins adsorption indicated its better hydrophilicity and proteins

antifouling property [38] as in phase diagram the binodar point shifted to higher

temperature and proportion of PVP between polymer matrix to pore surface decreased

with PVP content increasing. For the detection of troxeerutin in pharmaceutical dosage

forms Xiaofeng Yang et al. observed sensitivity of pharmaceutical [39] dosage in PVP

48

modified carbon paste electrode where PVP enhance the adsorption of the troxerutin to

electrode surface based on their hydrophobic property. PVP introduces its applications to

nanotechnology. Jin-Zhu Wu and Paul C. Ho in 2006 prepared nano sized realgar [40]

(As2S2) particles by cryo-grinding. Co-grinding realgar with PVP produced smaller and

more monodisperse suspension of nano particles are selected. The in vitro cytotoxic

effects of such nano sized realgar particles on selected human ovarian (CI 80-13S,

OVCAR-3) and cervical (HeLa) cancer cell line and significant anti-proliferation effect

of these realgar nanoparticals on these cancer cell lines results that CI80-13S with IC50

values of less than 1 m as As2S2 were most sensitive to nano sized realgar particles. In

vivo study remarks a considerable increase in urinary recovery of arsenic in rats after a

signal oral administration of the cryo-ground realgar particle suspension was observed.

Ranging from 58.5 to 69.6% of the administrated doses of arsenic was recovered in urine

in the first 48 h from the PVP and /or SDS co-ground preparations; whereas the original

realgar power gave a urinary recovery of only 24.9%. The finding suggested that size

reduction of realgar particles to nano levels could enhance its bioavailability

substantially. PVP based thin film usually behave as biosensor [41] as Tianbao Du et al.

prepared (PVP) composite films [42] on Pyrex glass substrates by the sol-gel dip- coating

[43] technique utilizing zinc acetate precursor. These composite films can be used as

biosensor for SOR and potentially for characterizing the antioxidant properties of fluids.

PVP as surfactant in an aqueous zinc nitrate solution was used to develop nanoporus

films by cathodic electrodepositing where PVP concentration had strong effects on the

grain sizes and surface morphologies of ZnO films as applicable to dyesensitized [44]

solar cells. PVP based gas sensors, PVP-modified [45] ZnO nanoparticales with different

molar ratios of Zn++: PVP were prepared by a sol-gel method [46] that exhibited excellent

sensitivity and selectivity to trimethylamine (TMA). The response and recovery time of

the sensor were 10 and 150s, respectively. Finally, the mechanism for the improvement in

the gas sensing properties was studied by Huixang Tang et al. Lisha Zhang also described

PVP as surfactant, has strong effects on the grain sizes and morphologies [47] of Bi2O3.

PVP described as coupler by Robert Y. Lochhead to develop stimuli-responsive

interfacial [48] coupling materials for nanocomposites that will enhance substrate

mechanical properties during use in biodegradable packaging materials. Hot melt

49

extrusion of PVP-co-vinyl acetate 64, Eudragit E100 and ethyl cellulose 20 cps, with

pressurized carbon dioxide was evaluated by Geert Verreck et al. to act as a temporary

plasticizer [49] as well as to produce a formed polymeric material. Polymeric PVP has

been used by Leon Farber et al. to modify the micro-mechanical properties [50] of during

material bridges of pharmaceutical excipients where PVP makes them amorphous, strong

and tough. The evasion properties of different materials [51] arising from various

symmetrical sites of Eu [III] due to the interactions between the complex and PVP

polymer has got considerable change as determined by Hong Guo Liu et al. Cadmium

Sulphide (CdS) 1-D nanocrystals [52] where prepared using a novel PVP-assisted

solvothermal method and the mechanism for the PVP assisted solvothermal synthesis of

CdS 1-D nanostructures was investigated by Wan Qinqing who described that the dosage

of PVP is a vital factor made by blending chitosan [53] with PVP were observed by Jing

Xi et al. and were found hydrophilic with water contact angles ranging from 590 to 690

which reduces cell adhesion, growth, and proliferation. The effect of PVP on the

corrosion resistance of steel reinforced concrete was assessed by measuring the corrosion

potential linear polarization resistance and AC impendence during 60 days immersion in

NaCl and NaCl +PVP solutions by A.A. Gurten et al. and observed that the resistance of

PVP mixed electrodes was also quite higher than the other electrodes and compressive

strength of concrete had increased approxymtelly 44% in the specimens containing PVP.

S.J.R. Simons et al. used PVP as binder in granulation [54] of pharmaceutical products.

PVP is characterized by high ability to create complex which is the reason that it has been

applied for the medicine as an agent with high sorption ability and in the textile industry

for. A. Ganatowski and J. Koszkul used (PVP) with low molecular mass and investigated

the influence of compatibilizer [55] and filler type on the propreties of chosen polymer

resins blends. Blends of poly ( -caprolactone) (PCL) and the polymeric antimicrobial

complex [56] PVP-iodine (PVP-I) to the adherence of a clinical isolate of Escherichia

coli was described, where due to the combined antimicrobial and biodegradable

properties these biomaterials after a promising strategy for the reduction in medical

devise related infection. Fe2O3 thin films containing dispersed Au nanoparticales were

prepared on nesa silica glass substrates, using Fe (NO3.9H2O-HAuCl4.9H2O-

CH3COCH2COCH3-CH3OC2H4OH) solutions containing PVP. It was reported that

50

quantum efficiency was further increased by modifying the microstructure of the film

electrodes [57] through the addition of PVP. The maximum incident photon to current

efficiency (IPCE) of about 20% was achieved in an Au-dispersed film prepared from a

solution containing PVP. PVP in coating solutions provided the fired films with an

increase in size of the grains and voids between them and in donor density, either of

which could contribute to the increased IPCE. Correlation between the relative humidity

of the strong medium and the mean dissolution time of theophylline from PVP tablets and

the size of free volume holes was reported. Positron annihilation life time spectroscopy

(PALS) measurements, performed parallel with the theophylline release study, showed

that the main reason for this correlation is the rearrangement of the pore structure of PVP.

The results suggest that the water-induced glassy to rubbery transition of the polymer

plays a significant role in the drug-release characterstics [58]. Jingtao Ma observed that a

common and fatal problem of the low-toxicity gel casting is the low flexural strength [59]

of green bodies. Flexural strength of green bodies was improved nearly by 30%, with

significant change in the property of sintered bodies when the addition amount of PVP is

2.8 wt %. Influence of PVP content on rheological properties [60] of Alumina

suspensions, their gelation time, and the microstructure of green and sintered bodies were

investigated. Yoshihisa Kaneda used PVP as a polymeric carrier to improve the plasma

half [61] of drugs in order to achieve an optimum drug delivery such as targeting or

controlled release. PVP showed the longer mean resident time (MRT) and was found

most suitable polymeric modifier for prolonging the circulation lifetime of a drug and

localizing the conjugated drug in blood PVP binding with proteins was carried out by J.

Fernandez in order to prevent adsorption of the enzyme [62] to membrane for internal

sequence analysis. The PVP is chemically inert which has good compatibility with

numerous film formers, water soluble binders and plasticizers. The viscosity of its

solution decreases with increase in temperature. With strong shearing on solution coating,

a clear and hard film is formed. PVP undergoes reversible association with iodine,

polyphenols, tannin, dyes, and toxins [63] and forms complexes with them. The lactam

group is saponified only by the action of concentrated acids, with formation of PVP

(gamma-amino) butyric acid [64]. The protective colloid action is utilized in dispersions

and in suspension polymerization. It is used as artificial blood plasma. In pharmacy, PVP

51

has wide spectrum of PVP uses: as a solubilizer, crystallization retarder, detoxifier [65],

tablet binding and coating agent and suspension stabilizer. PVP-Iodine is used as a

disinfectant and resistant to encrustation. The cross-linked insoluble popcorn PVP is used

for the clarification of beer and other beverage. The hardness, friability, porosity and

disintegration time of lactose [66] and starch placebo tablets are produced with PVP as it

suits as dry binder for direct comparison. It also helps in automation of sugar coating

process. PVP is characterized by its high ability to create complexes due to which it has

been applied for the medicine as an agent with high sorption ability and in the textile

industry [67 for stabilizing coloring agents. It is chemically and biologically indifferent

with regard to both acute toxicity and skin irritation. In feeding tests on rats with

radioactivity labeled PVP of average molecular mass 40,000, more than 99% was

excerted through the intestinal tract. Carcinogenicity of PVP was not observed in any of

the experimental procedure [68]. More than one million people have shown good

tolerance for PVP infusion as blood plasma substitute without side effects. But PVP is no

longer used for infusions because low molecular mass types which do not have a plasma-

expander action. Animal experiments have shown that larger molecules are stored in the

cells of reticuloendothelial system of spleen, the liver, and the lymph nodes, as well as in

bone marrow. However, during this PVP storage, neither morphological nor functional

damage has been observed.

2.4 Biological application of the polymer resin

Preventing bacterial growth as biocides and antimicrobials: Polymers and many additives

that are used to provide useful properties in compounds are vulnerable to attack by micro-

organisms [69]. However, antimicrobials can be added to plastics to increase their

resistance, which will maintain properties and boost product life. Plastic additives and

compounding rounds up some of the products on the market in this important field.

Antimicrobial additives and fungicides are added to plastics to increase their resistance to

micro-organisms such as bacteria, fungi and algae, which can cause black pitting, pink

staining or odour, impairment of properties, and reduction of product life [70]. Polymers

such as polysulphides and polyester-based polyurethanes are vulnerable, but the main

culprits for microbial growth are additives such as plasticizers, starch fillers, lubricants,

thickening agents, and oils. A main area is PVC, which is also used in many vulnerable

52

applications. Plasticized PVC film can be attacked by micro-organisms, especially fungi,

which use the plasticizer or other ingredients as a carbon source, producing discoloration,

bad odour, tackiness and eventual embrittlement over a period of time [71]. Microbial

attack can be prevented by incorporation of a fungi static agent during processing.

Biocides act by interfering with the metabolism of micro-organisms by blocking one or

more of the enzyme systems. However, to be effective, the additive should migrate to the

surface-a process that is influenced both by its chemistry and compatibility. Also

influential is the internal structure of the PVC film (ingredients), as well as the processing

conditions. Many chemicals have antimicrobial properties, but few are suitable for use in

plastics, requiring low cost, compatibility, thermal stability during processing,

environmental stability, and safe and easy handling [72]. Microbial agents must migrate

to the surface of the plastic and prevent bacterial growth. Fifty-eight fungi have been

tested for their ability to degrade a recalcitrant synthetic polymer polyamide-6, generally

known as nylon-6. Most of them were isolated from a factory producing nylon-6. After

preliminary screening, 12 strains were selected for submerged culture in a medium with

nylon fibres as the only N-source. No degradation was observed with the isolates from

the factory [73]. Wood degrading fungi from a culture collection, however, degraded

nylon after incubation for several weeks. Bjerkandera adusta bacteria is disintegrated the

fibres most efficiently, starting with the small transverse grooves, which deepened into

cracks [74]. The superficial layers crumbled to leave a thin inner core of the fibre, which

finally broke down into fragments. The remaining insoluble part of the nylon showed a

decrease in number average molecular mass from 16,900 to 5600 during 60-day

incubation. Its thermal properties, such as shifts in melting points and broadening of the

melting endotherms, were altered. The reduction of the amount of nylon and the

composition of the liquid phase indicated that part of the polymer was degraded into

soluble products. After 50 days, the total nitrogen content of the soluble fraction was 10-

fold higher than in the control sample. Manganese peroxidase, presumably responsible

for the degradation, was detected in the liquid phase. The study shows that only white rot

fungi are able to break down nylon-6. For the first time this polymer was shown to be

disrupted by B. adusta. The extent of the biodegradation indicates its potential for

application in nylon waste reduction [73]. Polymers with antibacterial activity have been

53

synthesized by chemical modification of poly(glycidyl methacrylate). The glycidyl

methacrylate was polymerized by the free radical polymerization technique. The poly

(glycidyl methacrylate) was hydrolyzed and was chloroacetylated using chloroacetyl

chloride. The chloroacetylated product was modified to yield polymers with either

quaternary ammonium or phosphonium salts. The antimicrobial activity of the modified

glycidyl methacrylate polymers has been examined against a variety of test

microorganisms by the cut plug and the viable cell counting methods using shake flask of

ten times diluted nutrient broth medium. All three polymers obtained were inhibitory to

the growth of Gram negative bacteria (Escherichia coli, Pseudomonas aeruginosa,

Shigella sp. and Salmonella typhae) and Gram positive bacteria (Bacillus subtilis and

Bacillus cereus) as well as the fungus (Trichophyton rubrum). It was found that the

growth inhibitory effect varied according to the structure of the polymer and the

composition of the active group and increased with increasing the concentration of the

polymer. The tested polymers showed more antimicrobial activity against Gram negative

bacteria and the fungus, whereas were less active against Gram positive bacteria. C-13

deisopropylated and/or C-7 oxidized resin acid derivatives were tested against various

microorganisms to determine structural features responsible for biological activity and to

determine the influence of the C-13 isopropyl group on antimicrobial activity. Test

results show that methyl cis and trans 7-oxo-13-deisopropyldehydroabietate and a

mixture of both isomers exhibited activity against fungi and bacteria.

Silver-based antimicrobials: Silver antimicrobial additives are also widely used in

plastics. The inert nature and antimicrobial efficiency of silver make it an attractive

option for the food processing and medical equipment industries. It is not toxic,

flammable or corrosive and will not cause bacteria to become resistant to antibiotics.

Silver-based antimicrobials work through an ion exchange mechanism that slowly

releases silver ions, which interact with the bonding sites on the microbe surface to

prevent bacteria from reproducing [75].

2.5 Pharmaceutical and industrial application of antifungal polymer

Microbial infection remains one of the most serious complications associated with the use

of many biomaterials. Paints and painted surfaces provide a particularly wide range of

different ecological niches that provide sites for microbial attachment. The individual

54

components of paint often provide biodegradable substrates. In water-borne paints, the

formulated product can be attacked during production in pre-scale storage and as the re-

usable residues [76]. Metal toxicity towards microorganisms is of environmental concern

because of possible inhibition of essential microbe-assisted processes. These metals are

toxic to the environment and their application is not short lived. If these materials are

attached to polymers, it would be ideal solution to overcome problems associated with

their toxicity. In addition, microorganisms serve as useful models for laboratory based

polymer-toxicity studies. Some polymers are potentially toxic to most organisms that

interact with cellular nucleic acids and enzyme active sites or absorbs on the cell wall

[77]. Many research studies are dealing with the biocidal activity of synthetic polymers.

Polymeric antimicrobial agents could be utilized in a variety of applications such as

paints, water treatment, coating on medical devices, food packaging, medical applications

and health care related materials studied the application of polymeric quaternary

ammonium materials as anion exchange resins in the disinfection of water supplies [78].

New directions in this area involve the synthesis of environmentally acceptable materials

that are insoluble but possess biocidal activities. Most of these recent studies are patents.

Water based emulsions are one of these aspects. This study is focusing on the evaluation

of the antifungal activities of the novel synthesized chelating water based emulsion

lattices and their silver complexes [79, 80]. A brief presentation of metal-uptake by two

fungal species is given to elucidate the various responses of the filamentous fungi to these

compounds.

2.6 Industrial and pharmaceutical application of antioxidants and antifungal

activity

Antioxidants are used as food additives to help guard against food deterioration.

Exposure to oxygen and sunlight are the two main factors in the oxidation of food, so

food is preserved by keeping in the dark and sealing it in containers or even coating it in

wax, as with cucumbers. However, as oxygen is also important for plant respiration,

storing plant materials in anaerobic conditions produces unpleasant flavors and

unappealing colors. Consequently, packaging of fresh fruits and vegetables contains ~8%

oxygen atmosphere. Antioxidants are especially important class of preservatives as,

unlike bacterial or fungal spoilage, oxidation reactions still occur relatively rapidly in

55

frozen or refrigerated food. These preservatives include natural antioxidants such as

ascorbicacid (AA, E300) and tocopherols (E306), as well as synthetic antioxidants such

as propylgallate (PG, E310), tertiarybutylhydroquinone (TBHQ),

butylatedhydroxyanisole (BHA, E320) and butylatedhydroxytoluene (BHT, E321) [81].

The most common molecules attacked by oxidation are unsaturated fats; oxidation causes

them to turn rancid [82]. Since oxidized lipids are often discolored and usually have

unpleasant tastes such as metallic or sulfurous flavors, it is important to avoid oxidation

in fat-rich foods. Thus, these foods are rarely preserved by drying; instead, they are

preserved by smoking, salting or fermenting. Even less fatty foods such as fruits are

sprayed with sulfurous antioxidants prior to air drying. Oxidation is often catalyzed by

metals [83], which is why fats such as butter should never be wrapped in aluminium foil

or kept in metal containers. Some fatty foods such as olive oil are partially protected from

oxidation [84] by their natural content of antioxidants, but remain sensitive to

photooxidation. Antioxidant preservatives are also added to fat-based cosmetics such as

lipstick and moisturizers to prevent rancidity. Antioxidants are frequently added to

industrial products. A common use is as stabilizers in fuels and lubricants to prevent

oxidation, and in gasolines to prevent the polymerization that leads to the formation of

engine-fouling residues [85]. They are widely used to prevent the oxidative degradation

of polymers such as rubbers, plastics, resins and adhesives that causes a loss of strength

and flexibility in these materials.

2.7 Pharmaceutical and industrial applications of blend polymer

Polymer blending is a simple, useful and attractive approach to obtain new compositions

with superior properties to their single component. It has been well-recognized that

polymer blends offer a key option in solving emerging application requirements [86-91].

The ability to combine existing polymers into new compositions with commercial

utilities offers the advantage of reduced research and development expense compared to

the development of new monomers and polymers to yield a similar property profile. An

additional advantage is the much lower capital expense involved with scale-up and

commercialization. Another specific advantage of polymer blends versus new

monomer/polymer compositions is that blends often offer property profile combinations

not easily obtained with new polymeric structures [92]. In the rapidly emerging

56

technology landscape, polymer blend technology can quickly respond to developing

needs. Polysulfone (PSF), polycaprolactone (PCL) and a combination of both

components are well known compositions that have widely been used for drug delivery

[93-94]. Controlled release of drugs from those polymers is therapeutically important for

enhanced medication efficacy after administration with a lowest dosage, where some

clinically-observed side effects for certain of toxic drugs can be minimized [95]. Property

modification as a result of suitable blending may not only manipulate the drug release

behavior but also influence the biocompatibility and the hemocompatibility of the

resulting blended polymers, the latter has been recognized as an important factor for a

number of blood-contacting implant devices. It is technique highly useful for as

medicochemical, cosmetics, pharmacetics, etc [96-101].

2.8 Pharmaceutical and industrial applications of phenol

Phenol is found naturally in decaying dead organic matter like rotting vegetables and in

coal. It was first isolated in 1834 from coal tar and this remained the main source of

phenol until the First World War. Phenol has a sweet odor that is detectable at 0.06 ppm,

which enables it to be used in an air freshener. In particular, phenol was used for

extermination by the Nazis before and during the Second World War. It is used in various

fields such as agricultural chemicals, disinfectants, antibacterial and antiseptics,

household hard surface cleaners (liquid), lubricating oils, other automotive chemicals,

paint and varnish removers, pharmaceutical preparations, synthetic resin and rubber

adhesives, wood office work surfaces (modular systems), versatile and thermoset resins

used in plywood adhesion, construction and the motorcar industry and a powerful

disinfectant and bacteria killer [102-105] etc. It is not only ideal for an air freshener but

also for other products like medicinal ointments and lotions [106]. It has antiseptic

properties and was used in antiseptic surgery. It is also the active ingredient in some oral

analgesics. It is also used in the production of drugs, herbicides, and synthetic resins

[107]. It is particularly important if the phenol is mixed with chloroform as a commonly-

used mixture in molecular biology for DNA & RNA purification from proteins [107]. It

is also used in the preparation of cosmetics including sunscreens, hair dyes, and skin

lightening preparations. Its moieties can be used to prevent the hair and skin ultraviolet. It

is also used in cosmetic surgery as an exfoliant, to remove layers of dead skin. It is also

57

used in phenolization, a surgical procedure used to treat an ingrown nail, in which it is

applied to the toe to prevent regrowth of nails.

2.9 Pharmaceutical and industrial applications of biomolecules

Biomolecules are essential for the normal growth and development of a multi cellular

organism. Using the genetic blue print inherited from its parents, a fetus begins to

develop, at the moment of conception the nutrients it absorbs. It requires certain vitamins

and minerals to be present at certain times. These nutrients facilitate the chemical

reactions that produce among other things, skin, bone, and muscles. Proteins are large

organic compounds made of amino acids arranged in a liner chain and joined together by

peptides bonds between the carboxyl and amino groups of adjoint amino acids residues.

Proteins and amino acids are an important part of our body. Several studies on the

physical, chemical, and biological properties of synthetic polypeptides have brought them

in describing their interactions in different ways. Proteins are the most abundant

biological macromolecules, occurring in all cells and all parts of cell. Relatively simple

monomeric subunits provide the key to the structure of the thousands of different

proteins. All proteins whether from the most ancient lines of bacteria or from the most

complex forms of life, are constructed from the same ubiquitous set of about twenty

amino acids, covalently linked in characteristic liner sequences. Cells use the different

alpha amino acids to synthesize proteins. The exact sequence of the different alpha amino

acids along the proteins chains the primary structure is correct the chain folds in certain

particular way to give it the shape it needs for its particular task. This folding of the

polyamide chain gives rise to a higher level of complexicity called the secondary and the

tertiary structure of protein. Because each of these amino acids has a side chain with

distinctive chemical properties, the group of 20 precursor molecules may be regarded as

the alphabets in which the language of protein structure is written. Hydrolysis of naturally

occurring proteins may yield different amino acids. They differs from each other in their

side chains or R-groups, which vary in structure, size and electric charge, and influence

the solubility of the amino acids in water as well as mixed solvents. The properties of

amino acids in hydrothermal solution are of intense interest for understanding metabolic

process in thermophilic bacteria and possible mechanism of life at deep ocean vents.

Because they exist as zwitterions, amino acids are useful probes to examine an effect of

58

dipole salvation on partial molar properties at elevated temperatures and pressure.

-alanine and L-leucine, amino acids have been taken for critical solution effect

on higher temperature. Glycine has been reported to act in biomedical applications as in

CST effect. L-alanine, which is present in mussel adhesive [108] proteins, a new class of

biologically derived materials that posses unique biocompatibility, bioactivity and

-alanine has been reported as additive in artificial intelligent

hydrogels [109] responding to external stimuli such as temperature and pH. As proteins

or amino acids chains are chemical foundation of living being, they are considered

important constituent intimately connected with chemical and biological changes that

establish life. The biological significance is unique, and compose an indispensable

substrate of life involving the phenomenon of growth and reproduction. J. Leiberg [110]

had put forward postulates like they differ only in physical state and not in composition

concluding that in plants and animals, the proteins are essentially similar in structure. An

electrostatic, covalent and Vander Walls forces of proteins play a key role in monitoring

the conformational states of them. Hence, the studies substantiate the residual forces of

molecule responsible for reorientation during solute-solvent and solute-cosolute-solvent

interactions. The biomolecules DL-alanine, L-proline, L-lucine, L-lysine are also highly

useful in nano medicinal and industrial fields [111-115].

2.10 Pharmaceutical and industrial applications of surfactants

The surfactant is a surface acting agent. It increases the solubility of the compounds.

Surfactants are usually organic compounds that are amphiphilic, which is divided with

hydrophobic and hydrophilic groups. Therefore, they are soluble in both organic solvents

and water. Dodecyltrimethylammoniumbromide (DTAB) has properties of disrupting

microorganism cell processes and active ingredients for conditioners [116]. It has

remarkable applications in biosciences [117]. It is also used in various fields such as

antistatic agents, detergents sanitizers, softener for textiles and paper products, phase

transfer catalyst [118], antimicrobials, disinfection agents, sanitizers, algaecide,

emulsifying agents and pigment dispersers [119, 120] etc.

Methyltrioctylammoniumchloride (MTOAC) is useful for preparing yields in strong base

conditions and antifungal agents [121-124] such as fluconazole. Fluconazole is a widely

used anti fungal agents especially as a first generation drug in the treatment of fungal

59

infections of vagina, mouth, throat, oesophagus, etc. Trimethylsulphoxoniumiodide

(TMSOI) is highly active pharmaceutical ingredient which is used in biochemical,

nutraceuticals, cosmetics, solution products and critical solvent products [125-128].

Orcinol is used in manufacturing protoactive and novolac resins for electronics industry,

UV protectors, stabilizers, antioxidants for plastics and rubbers. It is also used in

analgesics, food additives, fragrances, biocides, fungicides, dyes for pharmaceuticals and

food additives industry [129-133]. It is believed that it is lesser toxic as compared to other

resorcinols.

2.11 Pharmaceutical and industrial applications of critical solution

Liquids are more soluble with increase in temperature. Eventually a temperature reaches

when the liquids become completely miscible. This temperature is known as the critical

solution temperature or cosolute point. Hence upper critical solution temperature (UCST)

is a temperature below and above of which the two-phase liquid system develops a

single-phase liquid. As it is a system dependent parameter, hence for a particular system

like water and phenol its value is fixed and dependent to its nature. It is used as an

effective yardstick for additives added to water and phenol. UCST properties are always

of interest for several uses in nanotechnology, biotechnology and micro scale processes.

So the proteins, amino acids and vitamins are frequently used in several solubility based

processes like separation of proteins from their natural sources where the UCSTs are

useful [134]. The DTAB, TMSOI and MTOAC cationic surfactants and Orcinol are

highly used in biosciences for several purposes so their influence on solubility of solvents

assists the separation and extraction processes [135, 136]. The UCSTs are industrially

useful to develop the proteins, amino acids and vitamins based bionanoparticle for

biochips and DNA biotemplates technology. The critical solutions with proteins and

vitamins, amino acids and surfactants are useful for food scientists and biophysical

scientists. Temperature-dependent surfaces and interfacial kinetics remain relatively

unexploited in thin-film sensing applications that rely on optical surface-sensitive

techniques. The UCSTs with a wide range of additives have been serving a wider purpose

in solution engineering of immiscible solvents for interactions with industrially useful

molecules. The UCSTs with ionic, hydrophilic and hydrophobic interactions define cloud

60

points with additives of thermodynamic significance [137-141] with potential uses in

soaps, detergents, textiles, inks, paint and pigments, solvent extractions, and disinfectant

solutions. Industrially phenol is widely used as a disinfectant where its solubility in

different solutions is highly influenced by the ingredients of the solution [142, 143]. Its

aqueous solution with proteins, amino acids and vitamins could be of some use in

biotechnology and biophysics as it is used to inhibit the early degradation of fish, meat

etc.

61

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