Semi-synthetic Polymers Research Articles

Tissue engineered scaffolds for corneal endothelial regeneration: a material's perspective.

Currently, the treatment of corneal diseases caused by damage to the corneal endothelium requires a donor cornea. Because of their limited availability (1 donor cornea for 70 patients in need), researchers are investigating alternative approaches that are independent of donor tissue. One of them includes the development of a tissue engineered scaffold onto which corneal endothelial cells are seeded. In order to function as a suitable substrate, some of its essential properties including thickness, permeability, transparency and mechanical strength should meet certain demands. Additionally, the membrane should be biocompatible and allow the formation of a functional endothelium on the surface. Many materials have already been investigated in this regard including natural, semi-synthetic and synthetic polymers. In the current review, we present an overview of their characteristics and provide a critical view on the methods exploited for material characterization. Next, also the suitability of scaffolds to serve their purpose is discussed along with an overview of natural tissues (e.g. amniotic membrane and lens capsule) previously investigated for this application. Eventually, we propose a consistent approach to be exploited ideally for membrane characterization in future research. This will allow a scientifically sound comparison of materials and membranes investigated by different research groups, hence benefitting research towards the creation of a suitable/optimal tissue engineered endothelial graft.

English

Crude oil induced pollution on soil environment is an increasing trend due to incessant accidental release of this component into the environment. Bioremediation which is considered the most effective clean-up tool is faced with the challenge of sustained nutrient delivery to enhance and sustain the activities of oleophilic microbes. Slow release fertilizer (SRF) is a purposely designed system that releases nutrients in synchrony with sequential needs of organisms hence they provide optimized nutrient use efficiency. This approach aids in mitigating challenges associated with the conventional fertilizer application such as eutrophication, soil hardening, increased fertilizer loss rate and other environmental devastation. Superabsorbent polymers are hydrophilic gels as they exhibit the ability of swelling and retaining water which supports its use in SRF production. Most SAP used in practice are synthetic and semi-synthetic polymers with high production cost and environmentally unfriendly properties.  Natural based polymers such as guar gum, cellulose, chitosan, and starch are abundantly available from plant and other sources but most of these biopolymers have other application which may lead to scarcity for other uses. In most part of the world, enormous quantity of waste is generated which invariably causes pollution. World agro and industrial waste materials with little or no value is therefore recommended to be applied as SAP for SRF formulation. This review therefore provides insight on the potential use of controlled release fertilizer system as a useful tool in ensuring sustained nutrient delivery during bioremediation and also suggest more eco-safe and cost-effective approaches of SRF formulation. Key words: Hydrocarbons, encapsulation, degradation, organic fertilizer.

Polymers Blending as Release Modulating Tool in Drug Delivery

Different polymeric materials have been used as drug delivery vehicles for decades. Natural, semisynthetic, and synthetic polymers each have their own specific characteristics and, due to the physicochemical limitations of each polymer, tuning the release rate and targeting the active ingredient to a specific organ or site of action is a complicated task for pharmaceutical scientists. In this regard, polymer blending has been considered as an attractive approach to fabricate novel and unique drug delivery systems with modified physical and/or chemical characteristics. There are three major polymer blending approaches that are used for drug delivery purposes: physical mixtures, core-shell model, and block copolymer model. Each of these types of polymer blends could significantly affect the loading capacities and the kinetics of drug release from the relevant formulations. Drug release from these blended polymers can be tuned through the changes in temperature and pH of the environment, and physiochemical properties of the target organs. Furthermore, the possible molecular interactions among polymers and drug molecules can significantly affect the drug release profile from these blended polymeric micro- and nanocarriers. In this review, first of all, different types of polymers and their various applications in biomedical sciences have been discussed and smart or stimuli responsive polymers are introduced and categorized based on their nature. Then, the purpose of polymer blending in drug delivery systems has been discussed. Different types of polymer blends including physical mixtures, core-shell polymeric carriers, and block copolymers have been summarized with focus on the effect of polymer blending on encapsulated drug release profiles. Finally, the consequence of each blending approach on drug release profile and kinetics of drug release have been mentioned in tabular format.

Mechanically tunable photo-cross-linkable bioinks for osteogenic differentiation of MSCs in 3D bioprinted constructs

3D bioprinting technique renders a plausible solution to tissue engineering applications, mainly bone tissue regeneration, which could provide the microenvironment with desired physical, chemical, and mechanical properties. However, the mechanical and structural stability of current natural polymers is a critical issue in the fabrication of bone tissue-engineered scaffolds. To overcome these issues, we have developed 3D bioprintable semi-synthetic polymers derived from natural (sodium alginate, A) and synthetic (polyethylene glycol, PEG) biopolymers. In order to enhance the cross-linking properties and biocompatibility, we have functionalized these polymers with acrylate and methacrylate chemical moieties. These selected combination of natural and synthetic polymers improved the mechanical strength due to the synergistic effect of covalent as well as ionic bond formation in the hydrogel system, which is evident from the tested tensile data. Further, the feasibility of 3D bioprinting of acrylate and methacrylate functionalized PEG and hydrogels have been tested for the biocompatibility of the fabricated structures with human umbilical cord mesenchymal stem cells (UMSCs). Further, these bioprinted scaffolds were investigated for osteogenic differentiation of UMSCs in two types of culture conditions: namely, i) with osteoinduction media (with OIM), ii) without osteoinduction media (w/o OIM). We have examined the osteoinductivity of scaffolds with the activity of alkaline phosphatase (ALP) content, and significant changes in the ALP activity was observed with the stiffness of developed materials. The extent osteogenic differentiation was observed by alizarin red staining and reverse transcription PCR analysis. Elevated levels of ALP, RUNX2 and COL1 gene expression has been observed in without OIM samples on week 1 and week 3. Further, our study showed that the synthesized alginate methacrylate (AMA) without osteoinduction supplement with young's modulus of 0.34 MPa has a significant difference in ALP quantity and gene expression over the other reported literature. Thus, this work plays a pivotal role in the development of 3D bioprintable and photo-cross-linkable hydrogels in osteogenic differentiation of mesenchymal stem cells.

Methods for the Detection and Quantification of Micro and Nanoplastics- A Review

Over the past 35 years, synthetic or semi-synthetic polymers called “plastics” have been widely used across multiple fields due to their low cost, versatility, durability. Plastics have proved to be a boon to mankind. However, overuse of non- biodegradable plastics comes with its own downsides. Despite constant efforts to reuse and recycle plastics, these polymers substantially contribute towards the accumulation of debris hazardous to the environment. Plastic materials are slowly broken into fragments of micro- and nano plastics due to aging and weathering. Micro- and nano plastics were found capable of entering the food chain and hence are viewed as threats. This review paper revolves around methods used for the detection and quantification of micro- and nano plastics. Detection of micro- and nano plastics using methods like Raman spectroscopy, Infrared Spectroscopy, SERS, MALDI-TOF, and machine learning approaches are discussed here. The research efforts carried out in this article aims to further facilitate the R&D initiatives of Jozbiz Technologies.

The Numerical Analysis of Hyperelastic Properties in Commercial and Original Aloe Vera Gels

A basic purpose of a good healing patch is to reduce the reproduction of bacteria in the wounded area with minimal effect of mechanical properties. This study focuses on the basic mechanical and biomechanical properties of the material for a healing patch application with a new composition of biodegradable ingredients by using the estimation of hyperelastic models to fit with the experimental data and the comparison between the commercial Aloe vera gels and original Aloe vera leaves. This project was started with a material selection which is gelatine and Aloe vera leaves as the main ingredient. Secondly, the specimen sets undergo a uniaxial tensile test to obtain the raw data. For numerical phases, the conventional theory of large deformation based on hyperelastic constitutive equations and Stress-Strain Energy Theory were identified. The final step for this project is curve fitting between experimental data (Ogden and Mooney-Rivlin hyperelastic models). New parameters were carried out for healing patch materials made of hybrid biomaterials from the hyperelastic theory. The Ogden and Mooney Rivlin trends were closely followed by the curve fit presented with a minor difference. Overall, the original Aloe vera leaves’ values were Ogden (α=1.8792, µ=0.1881 Mpa) and Mooney-Rivlin (C1=0.0713, C2=0.0304) respectively. The significance of this project is to expand the knowledge about mechanical properties of natural polymers for wound healing application instead of depending on semi-synthetic polymers.

Polymeric Lipid Hybrid Nanoparticles (PLNs) as Emerging Drug Delivery Platform-A Comprehensive Review of Their Properties, Preparation Methods, and Therapeutic Applications.

Polymeric lipid hybrid nanoparticles (PLNs) are core–shell nanoparticles made up of a polymeric kernel and lipid/lipid–PEG shells that have the physical stability and biocompatibility of both polymeric nanoparticles and liposomes. PLNs have emerged as a highly potent and promising nanocarrier for a variety of biomedical uses, including drug delivery and biomedical imaging, owing to recent developments in nanomedicine. In contrast with other forms of drug delivery systems, PLNs have been regarded as seamless and stable because they are simple to prepare and exhibit excellent stability. Natural, semi-synthetic, and synthetic polymers have been used to make these nanocarriers. Due to their small scale, PLNs can be used in a number of applications, including anticancer therapy, gene delivery, vaccine delivery, and bioimaging. These nanoparticles are also self-assembled in a reproducible and predictable manner using a single or two-step nanoprecipitation process, making them significantly scalable. All of these positive attributes therefore make PLNs an attractive nanocarrier to study. This review delves into the fundamentals and applications of PLNs as well as their formulation parameters, several drug delivery strategies, and recent advancements in clinical trials, giving a comprehensive insight into the pharmacokinetic and biopharmaceutical aspects of these hybrid nanoparticles.

Recent Patents on Modified Release Oral Dosage Forms

Background: Conventional oral dosage forms have limited bioavailability and frequent dosing of the drug is needed to maintain the effective therapeutic concentration in the body. This results in poor patient compliance and fluctuations in the plasma drug levels, especially in the chronic diseases and disorders.
 Objective: To overcome such problems and to enhance the efficiency and bioavailability of the drug, modified drug delivery systems such as extended release delivery systems (controlled release; sustained release) and delayed release delivery systems are developed which can prolong the release and hence action of the drug in the body.
 Methods: Through this review, we throw the light on recent patents and patent applications on modified release systems pertaining to oral dosage forms. The various free patent search databases were used to collect and analyze the information on modified release delivery systems.
 Results: Modified release systems such as extended release and delayed release delivery systems have been found to be of great significance due to their advantages over immediate release dosage forms. These systems are formulated using various approaches, different types of release controlling polymers such as natural, semisynthetic and synthetic polymers and found to avoid the limitations of conventional oral dosage forms.
 Conclusion: Modified drug release systems have potential especially, in case of the chronic diseases, mental health disorders and lifestyle diseases and disorders. These systems have unique commercial advantages which will sustain the interest of both the researchers and the pharmaceutical companies.
 Keywords: Modified release systems, extended release systems, controlled release systems, sustained release systems, delayed release systems, oral dosage forms, multilayer dosage form, multilayered tablets

Design, physico-chemical assessment and pharmacokinetics of a non-toxic orodispersible film for potential application in musculo-skeletal disorder

Development of an ideal drug delivery system to get maximum bioavailability with fewer side effects is a challenge. The objective of the present research was to prepare fast dissolving orodispersible films (ODFs) for simultaneous administration of BCS class II drug (meloxicam (MX)) and tizanidine (TZ) using solvent casting method to improve the bioavailability of both drugs. ODFs were prepared by synthetic (polyvinyl alcohol), semisynthetic (hydroxypropyl methyl cellulose, HPMC; hydroxyethyl cellulose, HEC) and natural (xanthan gum) polymers. The prepared formulations were investigated for physico-chemical parameters, mechanical strength, surface morphology and in vitro and in vivo drug release studies. The prepared ODFs were also evaluated through stability studies and histopathology. The results indicated that disintegration time, tensile strength, folding endurance and pH of film surface of all formulations are in the range from 20 to 60 s, 10.87–21.75, >100 times and 4.09–4.87, respectively. In vitro drug release study indicated a fast and maximum release of MX and TZ from all formulations within 5 min. Scanning electron microscopy (SEM) and visual observation of all formulations have shown a smooth surface with homogenous distribution of all ingredients. Stability study of formulations for six months did not show any significant imperfection except a decrease in disintegration and dissolution time of all formulations due to water absorbing capacity of the polymers. In vivo study indicated the enhanced bioavailability of the both drugs. After complete evaluation of all formulations, it is concluded that the reported method of the preparation of ODFs can be used to improve the morphology of the films as well as the pharmacokinetics parameters of the drugs.

Polymer-Based Carriers in Dental Local Healing-Review and Future Challenges.

Polymers in drug formulation technology and the engineering of biomaterials for the treatment of oral diseases constitute a group of excipients that often possess additional properties in addition to their primary function, i.e., biological activity, sensitivity to stimuli, mucoadhesive properties, improved penetration of the active pharmaceutical ingredient (API) across biological barriers, and effects on wound healing or gingival and bone tissue regeneration. Through the use of multifunctional polymers, it has become possible to design carriers and materials tailored to the specific conditions and site of application, to deliver the active substance directly to the affected tissue, including intra-periodontal pocket delivery, and to release the active substance in a timed manner, allowing for the improvement of the form of application and further development of therapeutic strategies. The scope of this review is polymeric drug carriers and materials developed from selected multifunctional groups of natural, semi-synthetic, and synthetic polymers for topical therapeutic applications. Moreover, the characteristics of the topical application and the needs for the properties of carriers for topical administration of an active substance in the treatment of oral diseases are presented to more understand the difficulties associated with the design of optimal active substance carriers and materials for the treatment of lesions located in the oral cavity.

ENHANCEMENT OF THERAPEUTIC WINDOW OF METFORMIN HYDROCHLORIDE BY FABRICATION OF MICROSPHERES COMPRISING POLYMERIC INCULCATION WITH SEMI-SYNTHETIC AND SYNTHETIC POLYMERS BY IMPLEMENTATION OF BOX-BEHNKEN DESIGN

Objective: Innovative enhancement of therapeutic window of Metformin hydrochloride (MFH) and bioavailability through mucoadhesive microspheres by polymeric inculcation of hydroxypropyl methylcellulose K4M grade (HPMC K4M), hydroxypropyl methylcellulose K100M grade (HPMC K100M) and Kollidon SR grade (KS).
 Methods: Controlled release system was developed by incorporating semi-synthetic and synthetic polymers by modified solvent evaporation technique. Fabrication of mucoadhesive microspheres was designed by the implementation of experimental designs to obtain most optimum concentration of selected factors. The method was optimized by Box Behnken design (BBD) with selected factors as concentrations of semi-synthetic and synthetic polymer with stirring speed influence for the obtained responses that were mean particle size (Y1) entrapment efficiency of drug (Y2) and percent mucoadhesion (Y3). Microspheres were characterized for particle size, entrapment efficiency of drug, ex-vivo mucoadhesion study, in vitro study, Fourier transform infrared spectroscopy (FTIR), x-ray diffraction (XRD) detection and H1 Nuclear magnetic resonance (NMR) quantification for optimized formulation.
 Results: Implementation of response surface method software for BBD yielded stable microspheres with mean particle size 274 µm, entrapment efficiency of drug 85.07% and percent mucoadhesion 67.03% for optimized formulation F5.
 Conclusion: Bridging of MFH with the highly innovative combination of semi-synthetic and synthetic polymers yielded stable, cost-effective microspheres with improved bioavailability with controlled-release effect as till date no literature is available that provide information with selected polymeric combination and analytical characterization.

Contact angle analysis of surface topographies created by electric discharge machining

The objective of this work is to investigate the relationship between wettability and surface microgeometry of 6060 aluminum alloy created by electric discharge machining (EDM). The analyzes are enriched with the calculation of the correlation strengths between contact angles and geometric characteristics of surface topographies changing with the scale of observations. Surface topographies are measured by focus variation microscope and characterized with ISO parameters, geometric motifs and multiscale curvature tensor analysis. The wettability of the finished structures is investigated indirectly by contact angle measurements. The analysis were carried out using aqueous solutions of the semi-synthetic polymer, with different concentration and viscosity. The study showed that wetting behavior of aluminum alloy can be easily controlled through appropriate EDM finishing.

Pharmaceutical Considerations of Nasal In-Situ Gel As A Drug Delivery System

In situ gelling drug delivery systems have gained enormous attention over the last decade. They are in a sol-state before administration, and they are capable of forming gels in response to different endogenous stimuli, such as temperature increase, pH change and the presence of ions. Such systems can be administered through different routes, to achieve local or systemic drug delivery and can also be successfully used as vehicles for drug-loaded nano- and microparticles. Natural, synthetic and/or semi-synthetic polymers with in situ gelling behaviour can be used alone, or in combination, for the preparation of such systems; the association with mucoadhesive polymers is highly desirable in order to further prolong the residence time at the site of action/absorption. Nasal drug delivery is a better alternative of oral and parental route due to high permeability of Nasal epithelium, rapid drug absorption, avoid Hepatic first pass metabolism, increased bioavailability of drug, minimized local and systemic side effects, Low dose required, Direct transport into systemic circulation and CNS is also possible (passing blood brain barrier), Improved patient compliance, Self-Medication is Possible, prevent Gastro intestinal tract Ulceration. Recently, it has been shown that many drugs have better bioavailability by nasal route than the oral route. Thus, this review focuses on nasal drug delivery, various aspects of nasal anatomy and physiology, nasal absorption mechanism, advantages & disadvantage composition of in situ gel, application and In-situ gels evaluations.

Hydrogel as a Novel Drug Delivery System: Recent Advancements and Patents

Background: A semisolid gel-like preparation constitutes with the cross-linked polymers, which may easily swell in the presence of water and incorporate the amount of drug substance known as ‘Hydrogel.’ Objective: To prepare the review on the hydrogels, leading ennoblements, classification, mechanism, recent patents, and evaluation parameters. Methods: This review accrued by taking the help of online and offline journals, books, and other sources. This field includes new developments in the field of inventions in the novel drug delivery of hydrogels. Results: The impact of the formulation of hydrogels is attracting the focus of the researchers expeditiously because of their nature, three-dimensional structure, compatibility with the other excipients was found enormously useful in the biomedical applications and pharmaceutical industries, less time consuming, better sustained and prolonged the effect. Currently, hydrogels are growing expeditiously for the intensive work done by the use of natural, synthetic, and semi-synthetic polymers for the transformation of hydrophobic and hydrophilic drugs into hydrogels as compared to develop the conventional gels. Conclusion: The journey of hydrogel goes through with the numerous inventions research papers, reports, publications, and many other sources. The development arouses with the hydrogels in the use of wound dressing, making diapers, contact lens, etc. Nowadays, it is pivotally growing in the field of tissue engineering scaffolds, preparation of hydrophobic drugs into hydrogels, which is a critical challenge in prompt conditions.

Effect of carboxymethylcellulose sodium addition as stabilizer for physicochemical characteristic of purple sweet potato fortified yogurt (Ipomoea batatas L.)

The yoghurt consisted of low-fat milk, three bacterial strains starter, which included: L. bulgaricus ATCC 11842, L. plantarum ATCC 8014, and B. longum (1:1:1); purple sweet potato puree ( Ipomoea batatas, L.) and carboxymethylcellulose sodium with the concentration of 0.6%, 1.2%, and 1.8%. Purple sweet potato fortification in yogurt can prevent hypercholesterolemic conditions because it inhibits lipid and sugar absorption in the intestine. Unfortunately, there is one shortcoming in the production of yogurt which affects the final product quality. This shortcoming is in the decrease in the air holding capacity (whey off) during the production due to the pH level within the isoelectric point of casein. This causes precipitation and phase separation. This study will add a stabilizer to the formula to overcome it. The stabilizer used is carboxymethylcellulose sodium, which is semi-synthetic water-soluble ester polymer cellulose. This study aimed to determine the optimal concentration of carboxymethylcellulose sodium and its effect on purple sweet potato yogurt's physicochemical and organoleptic properties. The product quality evaluations were on organoleptic evaluation, density, viscosity, and pH level. Centrifugation and freeze-thaw tests were also performed to evaluate product stability. The results showed that carboxymethylcellulose sodium could maintain the stability of purple sweet potato yogurt by binding the air content, increasing consistency, and smoothing the texture even though it did not affect the freezing point of the product. This study gave the best results for purple sweet potato yogurt with 1.2% carboxymethylcellulose sodium concentration.

Current Status of Mucoadhesive Gel Systems for Buccal Drug Delivery.

Buccal drug delivery is a fascinating research field. Gel-based formulations present potent characteristics as buccal systems since they have great physicochemical properties. Among the various gels, in situ gels are viscous colloidal systems consisting of polymers; when physiological conditions change (pH, temperature, ion activation), they are transformed into the gel phase. These systems can improve bioavailability. Other systems, such as nanogels or emulgels can also be applied for buccal delivery with promising results. Polymeric gel-based systems can be produced by natural, semisynthetic, and synthetic polymers. Their main advantage is that the active molecules can be released in a sustained and controllable manner. Several gels based on chitosan are produced for the entrapment of drugs demonstrating efficient retention time and bioavailability due to chitosan mucoadhesion. Besides polysaccharides, poloxamers and carbopol are also used in buccal gels due to their high swelling ability and reversed thermal gelation behavior. Herein, the authors focused on the current development of mucoadhesive gel systems used in buccal drug delivery. After explaining buccal drug delivery and mucoadhesion, various studies with hydrogels, in situ gels, and nanogels were analyzed as buccal gel systems. Various mucoadhesive gel studies with mucoadhesive polymers have been studied and summarized. This review is presented as valuable guidance to scientists in formulating buccal mucoadhesive drug delivery systems. This review aimed to assist researchers working on buccal drug delivery by summarizing buccal drug delivery, mucoadhesion, and buccal mucoadhesive gel systems recently found in the literature.

Synthetic, Natural, and Semisynthetic Polymer Carriers for Controlled Nitric Oxide Release in Dermal Applications: A Review.

Nitric oxide (NO•) is a free radical gas, produced in the human body to regulate physiological processes, such as inflammatory and immune responses. It is required for skin health; therefore, a lack of NO• is known to cause or worsen skin conditions related to three biomedical applications— infection treatment, injury healing, and blood circulation. Therefore, research on its topical release has been increasing for the last two decades. The storage and delivery of nitric oxide in physiological conditions to compensate for its deficiency is achieved through pharmacological compounds called NO-donors. These are further incorporated into scaffolds to enhance therapeutic treatment. A wide range of polymeric scaffolds has been developed and tested for this purpose. Hence, this review aims to give a detailed overview of the natural, synthetic, and semisynthetic polymeric matrices that have been evaluated for antimicrobial, wound healing, and circulatory dermal applications. These matrices have already set a solid foundation in nitric oxide release and their future perspective is headed toward an enhanced controlled release by novel functionalized semisynthetic polymer carriers and co-delivery synergetic platforms. Finally, further clinical tests on patients with the targeted condition will hopefully enable the eventual commercialization of these systems.

Polyhydroxyalkanoates: An Exotic Gleam in the Gloomy Tale of Plastics

Polyhydroxyalkanoates (PHAs) are bio-polyesters of hydroxyalkanoates that accumulate intracellularly in case of prokaryotes, as cytoplasmic granules, under carbon rich and paucity of nitrogen, phosphorous, sulphur and oxygen where it can serve as carbon and energy source under nutrient limiting condition and/or environmental stress conditions. In adverse growth conditions, many bacteria have ability to store nutrients in form of PHA granules using their specific metabolic pathways during stationary growth phase, in the presence of high levels of carbon containing nutrient sources. Bacterial PHAs have generated attention as an alternative to petroleum derived synthetic plastics. It possesses the characteristic physico-chemical properties comparable to the synthetic plastics. These properties of PHAs can be improved by blending of PHAs with other natural polymer like starch, cellulose and semisynthetic polymers like poly lactic acids and polycaprolactones. Being eco-friendly, biodegradable and biocompatible; major PHAs such as, Polyhydroxybutyrate (PHB) and Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) have found numerous vital applications in pharmaceutical, biomedical, textile, cosmetic, agricultural, treatment of waste water and have been successfully employed for Food packaging industries. This review provides a comprehensive knowledge about the world of PHAs covering its major aspects, namely its chemical nature and structure, biosynthesis, various methods of screening of potential PHA producing bacteria along with properties, several techniques used for its recovery and further characterization.

Natural polymers in pharmaceutical drug delivery: A review

In pharmaceutical formulation two main ingredients are required which is API and excipient. And excipient contains many components which plays vital role in manufacturing of dosage form as well as improve pharmaceutical parameters of the dosage form. Polymers used in any dosage form as excipient. Polymers have influencing capacity towards drug release and should be compatible, stable, non-toxic and economic etc. Generally, polymers are classified into three categories i.e natural, semi-synthetic and synthetic polymers. Nowadays, many pharmaceutical companies inclined towards using natural polymers due to many problems created with drug release and side effects. Polymers plays various application in formulation as excipient like to provide uniform drug delivery, rate controlling agent, taste masking agent, protective and stabilizing agents, etc. So that this review discuss about various natural polymers, there advantages over synthetic polymers and role of polymers in designing drug delivery system.

Plastic toy soldiers, a lost battle? – an analytical perspective

The conservation and preservation of museum collections requires a detailed understanding of their constituent materials which are often natural, synthetic or semi-synthetic polymers. The use of a wide variety of instrumental techniques can give an extraordinary amount of quality information, by delivering complementary data regarding composition and structure. This study was triggered by the Oporto Military Museum (Museu Militar do Porto) conservators who observed that a set of plastic toy soldiers dating back to the middle of the 20th century from the museum exhibition started to present severe and accelerated degradation process. With this is mind, the authors envisaged a methodology for the characterisation of these soldier toys that compromised elemental, structural and morphologic analysis, to allow the identification of polymers, their additives, and the degradation products. The methodology comprised stereoscopic microscopy and VP-SEM-EDS to recognize the micromorphology, ATR-FTIR to identify the polymer, 1H and 13C NMR to identify their additives, and micro-XRD to identify degradation products with a crystal structure. With this complementary analytical approach the composition of the toy soldiers was identified as being made of cellulose acetate plastic with triphenyl phosphate and dimethyl phthalate as major additives, and crystallyne efflorescence of triphenyl phosphate were identified as a degradation product. This methodology shows to be very adequate for a detailed characterization of plastic artefacts in museum environments.