Water Vapor Permeability Of Films Research Articles

Preparation of pH-Responsive Films from Polyvinyl Alcohol/Agar Containing Cochineal for Monitoring the Freshness of Pork.

This study reported the production of pH-responsive films based on 8 wt% polyvinyl alcohol solution/0.2 wt% agar solution incorporated with cochineal-loaded starch particles (CSN) (2, 4, 6 and 8 wt% on agar basis) by a casting process. Results revealed that CSN presented obvious color changes over the pH range of 2-12. FTIR, XRD spectra and SEM micrographs presented that the incorporation of CSN formed new hydrogen bonds with a matrix and a tighter network structure. A certain improvement was observed in the color stability, swelling index and functional properties (antimicrobial and antioxidant activities) but water solubility, water vapor permeability and water contact angle of the pH-responsive films were decreased by the addition of CSN. The release of cochineal was a rate-limiting step following the Korsmeyer-Peppas model. The agar/polyvinyl alcohol film containing 6% CSN (PVA/GG-6) exhibited the best sensitivity for ammonia detection and its limit of detection was 35.4 ppm (part per million) for ammonia. The application trials showed that the PVA/GG-6 film presented different color changes for pork freshness. Hence, these pH-responsive films can be used as potential packaging materials for tracking the freshness of protein-rich fresh food in a non-destructive way.

Preparation and characterization of soy protein isolate films by pretreatment with cysteine.

The effect of cysteine concentration on the viscosity of soy protein isolate (SPI)-based film-forming solution (FFS) and physicochemical properties of SPI films was investigated. The apparent viscosity of FFS decreased after adding 1mmol/L cysteine but did not change after adding 2-8mmol/L cysteine. After treatment with 1 mmol/L cysteine, the film solubility decreased from 70.40% to 57.60%, but the other physical properties did not change. The water vapor permeability and contact angle of SPI films increased as cysteine concentration increased from 4mmol/L to 8mmol/L, whereas the film elongation at break decreased. Based on scanning electron microscopy and X-ray diffraction results, cysteine crystallization could be aggregated on the surface of SPI films treated with 4 or 8mmol/L cysteine. In conclusion, pretreatment with approximately 2mmol/L cysteine could reduce the viscosity of SPI-based FFS, but did not change the physicochemical properties of SPI films.

Incorporation of α-Tocopherol into Pea Protein Edible Film Using pH-Shifting and Nanoemulsion Treatments: Enhancing Its Antioxidant Activity without Negative Impacts on Mechanical Properties.

The aim of this study is to develop an antioxidant film based on pea protein isolate (PPI) without sacrificing the packaging properties. To achieve this, α-tocopherol was incorporated to impart antioxidant activity to the film. We investigated the effects on film properties resulting from the addition of α-tocopherol in a nanoemulsion form and pH-shifting treatment of PPI. The results revealed that direct addition of α-tocopherol into un-treated PPI film disrupted film structure and formed a discontinuous film with rough surface, and thereby significantly decreasing the tensile strength and elongation at break. However, pH-shifting treatment in combination with the α-tocopherol nanoemulsion, formed a smooth and compact film, which greatly improved the mechanical properties. It also significantly changed the color and opacity of PPI film, but had little effects on film solubility, moisture content, and water vapor permeability. After the addition of α-tocopherol, the DPPH scavenging ability of PPI film was greatly improved and the release of α-tocopherol was mainly within the first 6 h. Additionally, pH-shifting and nanoemulsion did not affect the film's antioxidant activity nor the release rate. In conclusion, pH-shifting combined with nanoemulsion is an effective method to incorporate hydrophobic compounds such as α-tocopherol into protein-based edible films without negative impacts on film mechanical properties.

A Comparative Study of the Properties of Gelatin (Porcine and Bovine)-Based Edible Films Loaded with Spearmint Essential Oil

Gelatin (bovine/porcine)-based edible films are considered as an excellent carrier for essential oils (EOs) to preserve food quality and extend their shelf life. Spearmint essential oil (SEO) is known for its potential antioxidant and antimicrobial effects; nevertheless, its food applications are limited due to the volatile nature of its active components. Thus, edible films loaded with essential oil can be an alternative to synthetic preservatives to improve their food applications. In the present study, the effect of SEO addition was investigated on the physicochemical properties of bovine and porcine gelatin films, and antioxidant activity was assessed. GCMS (Gas chromatography mass spectrometry) analysis revealed the presence of carvone (55%) and limonene (25.3%) as major components. The incorporation of SEO into the films decreased the opacity, moisture content, water solubility, and elongation at break of bovine and porcine gelatin films. However, with the addition of EO, the thickness and water vapor permeability of bovine and porcine-based gelatin films increased. Moreover, the addition of SEO increased the tensile strength (TS) of the porcine-based film, whereas bovine samples demonstrated a decrease in tensile strength. XRD (X-ray diffraction) findings revealed a decrease in the percentage crystallinity of both types of gelatin films. SEM (scanning electron microscope) results showed the changes in the morphology of films after the addition of SEO. Antioxidant properties significantly increased with the incorporation of EO (p < 0.05) when compared with control films. Therefore, the addition of SEO to gelatin-based edible films could be an effective approach to prepare an active food packaging material to prevent food oxidation.

Composite films based on carboxy methyl cellulose and sodium alginate incorporated Thymus vulgaris purified leaves extract for food application: Assessment, antimicrobial and antioxidant properties

The current study was conducted to develop biodegradable films with matrix composed from carboxymethyl cellulose (CMC), sodium alginate (SA) and different concentrations from Thymus vulgaris purified leaves extract (TVE). The color properties, physical properties, shape of surface, manners of crystallinity, mechanical properties and thermal properties of produced films were investigated. The continuous addition of TVE up to 1.6 % inside films matrix imparted the yellow color of extract that increased opacity to 2.98 and reduced moisture, swelling, solubility and water vapor permeability (WVP) of films up to 10.31 %, 30.17 %, 20.18 % and (1.12× 10−10 g.m−1 s−1 pa−1), respectively. Furthermore, the surface micrographs showed smoother surface after using small concentrations of TVE and turned to irregular with rough surface at higher concentrations. The FT-IR analysis indicated typically bands that demonstrated physical interaction between TVE extract and CMC/SA matrix. The fabricated films showed suitable thermal stability with decreasing trend by incorporation of TVE inside CMC/SA films. Furthermore, the developed CMC/SA/TVE2 showed significant effects on preserving the levels of moisture content, titrable acidity, force to puncture and sensory properties of cheddar cheese during cold storage days compared with commercial packaging materials.

Transglutaminase Cross-Linked and Lysozyme-Incorporated Antimicrobial Tilapia Collagen Edible Films: Development and Characterization.

To improve the mechanical properties and confer antimicrobial activity, transglutaminase (TGase) was used as a cross-linking agent and lysozyme (LYS) was incorporated as an antimicrobial agent to prepare novel active tilapia collagen (TC) films. While the difference in visual appearance was not obvious, the LYS incorporation increased the opacity of TC films. The water vapor permeability of all TGase cross-linked TC films was significantly (p < 0.05) lower than that of the control film (prepared without TGase and LYS). In addition, while the tensile strength and Young's modulus of all TGase cross-linked TC films were significantly (p < 0.05) higher than those of the control film, elongation at break of all TGase cross-linked TC films was significantly (p < 0.05) lower than that of the control film. LYS incorporated TC films showed antimicrobial activity against E. coli, Staphylococcus aureus, Enterococcus faecium, Bacillus subtilis and Pseudomonas fluorescens. Collectively, TC films with improved physiochemical properties and antimicrobial activity have a good potential to serve as active food packaging materials.

Effect of drying rate on the physicochemical properties of soy protein isolate-soy oil emulsion films

The effect of drying rate on physicochemical properties of emulsion films prepared from soy protein isolate (SPI) and soy oil was investigated. No changes were observed in emulsion micromorphology during 60 min of drying at a rate of 0.05 g s−1 m−2, whereas the emulsion droplet size increased with the drying rate. Phase separation was formed in emulsion films prepared at drying rate of 0.05 g s−1 m−2, but it vanished with increased drying rate. Tensile strength (TS) and elongation at break (EAB) of films prepared at drying rate of 0.05 g s−1 m−2 were 7.95 MPa and 47.58%, respectively. No change was observed in TS with increased drying rate, whereas EAB increased first and then decreased. When the drying rate increased, the water vapor permeability, contact angle, and thermal stability of films increased, whereas the opacity value and infrared peak intensities that represent oil on film’s upper surfaces decreased.

Effect of hydroxypropyl-β-cyclodextrin and lecithin co-stabilized nanoemulsions on the konjac glucomannan/pullulan film

In this study, the various ratio of hydroxypropyl-β-cyclodextrin (HPCD) to lecithin (LEC) was 0:1, 0.5:1, 1:1, 1.5:1 and 2:1 (w/w) co-stabilized cinnamon essential oil (CEO) nanoemulsions were prepared. These nanoemulsions were successfully incorporated in the konjac glucomannan/pullulan polysaccharides-based film matrix. The composition of nanoemulsions and the effect of various nanoemulsions on rheological, mechanical, Water vapor permeability, optical, color, morphology properties, and CEO retention rate of the composite films were characterized. The results demonstrated that HPCD and LEC nanoemulsions had small particle size under 120 nm and high stability during 21 days storage, the incorporation of nanoemulsions reduced the viscosity of film-solution, transmittance, Water vapor permeability and mechanical properties of films, but an appropriate HPCD content 1:1 w/w of nanoemulsions could restored the mechanical properties of the films. Otherwise, 1:1 w/w of nanoemulsion film also exhibited a more compact and uniform structure, Furthermore, 2:1 w/w of nanoemulsion films with high retention rate of CEO, and the antioxidant and better antibacterial activities against E. coli and S. aureus. The nanoemulsion films utilized in this study also prolonged the shelf life of Agaricus bisporus mushrooms and cherries while maintaining their commercial value.

Simulation of hydrophobic lotus leaves for preparing hydrophobic starch blending films based on starch-based graphite oxide carbon

Inspired by the hydrophobic mechanism of lotus leaf, hydrophobic starch blending films based on starch-based graphite oxide carbon(S-GOCs) was synthesized, while nano calcium carbonate (nano-CaCO3) and hydrophobic plasticizer (acetyl tributyl citrate, ATC) were also introduced for further improving its water resistance. The TEM, SEM, XRD, and FTIR characterizations were used to analyze the properties of S-GOCs. With increased addition of the S-GOCs, the water contact angle (θw) increased prominently (θw: from 35.5° to 91.5°), the moisture content (MC) and the water vapor permeability (WVP) of the starch blending films significantly decreased (MC: from 22.19% to 14.12%; WVP: from 3.86 to 3.27 g m m−2 s−1 Pa−1). The addition of the nano-CaCO3 and ATC further promoted its waterproof properties with the highest θw, the lowest MC, and WVP (θw = 112.2°, MC = 11.15%, WVP = 2.88 g m m−2 s−1 Pa−1). Although the S-GOCs resulted in a higher volume dissolution (the total soluble matter (TSM) increased from 26.26% to 32.13%), the incorporation of nano-CaCO3 and ATC could minimize the solubility of the films (TSM = 23.40%). Careful evaluation of tensile strength (TS) and elongation at break (E) of the films has concluded that the S-GOCs could make the films more flexible, and the extra addition of nano-CaCO3 and ATC have no adverse effect on this balance. Combined with the result of surface free energy and the analysis of AFM and FTIR, the hydrophobic mechanism of the starch blending films was illustrated, which was due to the synergistic effect of reducing surface free energy, improving surface roughness and structure water resistance. Finally, a simple application in the packing field was developed to envisage the prospect of starch-blending film.

Application of Poultry Gelatin to Enhance the Physicochemical, Mechanical, and Rheological Properties of Fish Gelatin as Alternative Mammalian Gelatin Films for Food Packaging.

This study aimed to describe the properties of cold water fish gelatin (FG) blended with poultry gelatin (PG) for a production of a sachet containing olive oil. To find a desirable film, the different ratio of FG-PG-based films were characterized in terms of mechanical properties. As the proportion of PG in PG-FG-based increased, the tensile strength and Young's modulus were increased, and the elongation at break and heat seal strength of the films were decreased. The 50-50 film had favorable characteristics to use as a sachet. The amount of acid index and peroxide of the oil stored in the sachets after 14 days showed that there is a significant difference (p < 0.05) between the films. The barrier properties of the films including the water vapor permeability and oxygen permeability of films were increased from 1.21 to 4.95 × 10-11 g m-1 Pa-1 s-1 and 48 to 97 cm3 mµ/m2 d kPa, respectively. Dark, red, yellow, and opaque films were realized with increasing PG. Fourier transform infrared (FTIR) spectra approved a wide peak of approximately 2500 cm-1. The rheological analysis indicated that, by adding PG, viscosity, elastic modulus (G') and loss modulus (G'') were increased significantly (p < 0.05) about 9.5, 9.32 and 18 times, respectively. Therefore, an easy modification of FG with PG will make it suitable for oil sachet packaging applications for the food industry.

Effects of pre-emulsion prepared using sucrose esters with different hydrophile-lipophile balances on characteristics of soy protein isolate emulsion films

The preparation of emulsion films using pre-emulsification has received extensive attention due to the enhancement of oil binding capacity. However, the different effects of water in oil (W/O) and oil in water (O/W) pre-emulsions on the physicochemical properties of films are still unclear. Therefore, the soy protein isolate (SPI) based emulsion films were prepared by W/O or O/W pre-emulsion using sucrose esters with different hydrophile-lipophile balances to investigate the properties of SPI emulsion (SPIE) films. The viscosity, storage moduli, and loss moduli of film-forming solutions (FFSs) with O/W pre-emulsion were higher than those of FFSs with W/O pre-emulsion. The oil droplets of FFSs with W/O pre-emulsion were large and uneven, and the oil droplet size increased after drying. Phase separation and macroporous network appeared in cross-sectional of SPIE films with W/O pre-emulsion according to scanning electron microscope images. Meanwhile, the SPIE films with W/O pre-emulsion demonstrated higher oil concentration and hydrophobicity on the upper surface compared with the SPIE films with O/W pre-emulsion. Low tensile strength, glass transition temperature, and high elongation at break and transparency value of SPIE films with O/W pre-emulsions were founded. The water vapor permeability of SPIE films with W/O pre-emulsion increased with the addition of oil, whereas the opposite trend appeared in that with O/W pre-emulsion. In conclusion, the structure and porosity of emulsion films could be affected by the pre-emulsion types, which can determine the application ranges.

Effects of curcumin, phycocyanin, or modified lycopene colorants on the physicochemical and sensory properties of whey protein–cellulose nanocrystal packaging films

To utilize natural hydrophobic/hydrophilic colorants to manufacture good quality and attractive packaging films, we investigated the effects of natural colorants (curcumin, phycocyanin, modified lycopene, and their mixed colorants) on the physicochemical and sensory properties of whey protein isolate–cellulose nanocrystal packaging film. Owing to the improvement in hydrophobicity and spatial density, moisture content (MC) and water vapor permeability (WVP) of films containing curcumin were reduced by 16.91% and 8.49%, respectively, in contrast to that, MC and WVP increased by 10.75% and 4.09%, respectively, in film containing modified lycopene. Mechanical testing, infrared spectra, and X-ray diffraction revealed the retention of structural properties of protein matrix. Rate-All-That-Apply evaluation indicated that films containing colorants enriched tactile and visual sensory characteristics. The eye tracking testing of packed foods showed that preferential attraction depends on the color of the food itself. Thus, a consumer‐oriented multi-colored packaging film with good performance was achieved.

Physicochemical and functional properties of chitosan-based edible film incorporated with Sargassum pallidum polysaccharide nanoparticles

The blending of different matrixes and the addition of functional factors may challenge the compatibility of edible films, thus affecting their basic properties. In this study, a novel nano-polysaccharide based edible film (nSPP/CH) was developed by blending Sargassum pallidum polysaccharide nanoparticles (nSPP) with chitosan (CH). The compatibility, physicochemical, and fruit preservation properties of nSPP/CH were investigated. The results indicated that compared with native polysaccharide-based edible films, nSPP/CH exhibited thinner thickness, higher tensile strength, and greater elastic modulus. Fourier transform-infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) analysis showed good compatibility between nSPP and CH through internal forces to form a stable structure. Moreover, nSPP/CH showed a good cherry preservation ability to cherries by inhibiting the respiration intensity and weight loss rate of cherries. Furthermore, the addition of thymol could improve the surface hydrophobicity and antimicrobial effect of nSPP/CH. However, the mechanical properties and water vapor permeability of nSPP/CH incorporated with thymol were decreased. Scanning electron microscope (SEM) analysis showed that the nano-polysaccharide encapsulated thymol through cavity structure was conducive to the dispersion of thymol and enhanced the compatibility of film matrixes, thus decreasing the water vapor permeability of edible film. These results suggest that nSPP/CH incorporated with thymol might be expected to be a new kind of natural green edible film to extend the shelf life of fruits.

A sustainable approach on the potential use of kale puree in edible wraps

Edible films can be used to prevent food spoilage, and investigations in this regard are paramount. When prepared alongside biopolymers, these materials become totally biodegradable in a short period of time, decreasing the amount of solid residues discarded into the environment. The ingestion of fruits and vegetables has increased in the last decades due to significant health benefits, and their durability comprises an important parameter for their marketing and use. Vegetables come in a variety of colors, sizes and shapes, comprising relevant features for their commercialization and packaging and for final consumers. In this regard, kale leaves are highly consumed in Brazil and new alternatives to improve their physical and organoleptic characteristics for novel applications, such as food wraps and in the replacement of high perishability leaves, are of interest in this scenario. Thus, the aim of the present study was to develop kale puree and sodium alginate films and evaluate their solubility, mechanical and thermal properties and water vapor permeability, focusing on improving their physical and organoleptic properties. The films were prepared by casting sodium alginate solutions with the addition of kale puree employing a film generator. Puree incorporation reduced film water vapor permeability and solubility. Pure alginate films presented a contact angle of 50 ± 1°, increasing to 62 ± 2° with the addition of kale puree. The same was noted for the alginate film that, when cross-linked with kale puree displayed an angle increase of 72 ± 5° This behavior may be due to interactions between these components and the hydrophobic phases. Calcium chloride was added for film crosslinking, contributing to biopolymer chain separation and mobility. This study highlights important issues concerning the use of vegetables in the production of edible films, especially biodegradable films, and emphasizes the importance of their development, due to reduced environmental impacts, low costs and the fact that they comprise a renewable resource.

Development and characterization of antioxidant bilayer film based on poly lactic acid-bitter vetch (Vicia ervilia) seed protein incorporated with Pistacia terebinthus extract for active food packaging

This study focuses on designing an active bilayer food package film based on polylactic acid (PLA) and bitter vetch seed protein incorporated with Pistacia terebinthus extract (PTE). The effect of PTE on the physicochemical, barrier, structural, mechanical, and antioxidant properties of the active film was determined. Moisture content, water solubility, and water vapor permeability (WVP) of the active films indicated that the addition of PTE increased its suitability for food packaging. FE-SEM micrographs illustrated that the resulting films had a smooth and dense surface, describing a continuous network of protein molecules within the film structure. FTIR analysis displayed the physical interaction between PTE and the film polymer. XRD revealed an increase in the crystallinity of the active films. The resulting active film had a low migration rate (<7%) of phenolic compounds into fatty food simulant. Notably, the addition of PTE significantly (P ≤ 0.05) decreased the tensile strength and Young's modulus (from 15.13 and 315.98 MPa to 14.07 and 254.07 MPa, respectively). Concurrently, there was an increase in the elongation at break of the active films (from 23.19 to 75.60%), indicating higher flexibility compared to control films. Additionally, the incorporation of PTE improved the thermal properties of active films. The antioxidant capacity of the designed films was measured based on their DPPH radical scavenging activity, revealing that the antioxidant capacity of the control film increased from 44.65% to 59.72% in the active film containing 15% PTE. In conclusion, the prepared bilayer film can effectively be used as an active food package for sensitive foods to oxidation.

Effect of cellulose nanocrystals-loaded ginger essential oil emulsions on the physicochemical properties of mung bean starch composite film

The poor antibacterial and water resistance of starch film hinder its application in packaging and preservation field. In this study, the green composite films were prepared via incorporating ginger essential oil (GEO) Pickering emulsions stabilized by tempo-oxidized cellulose nanocrystals (TOCN) into a starch-based film-forming matrix. The results showed the TOCN-loaded GEO emulsion dispersed well in the mung bean starch film. The antibacterial activity and tensile strength (TS) of the composite films were improved with the insertion of TOCN-loaded GEO. When the amount of TOCN was 1.0 wt% and the GEO dosage was 22%, compared with the control film, the water vapor permeability of the composite films declined by 60.3%, and the TS improved by 25.0%, and the composite films also showed high antibacterial activity. Additionally, the study on storage ability showed that the new compound starch-based films had a better storage effect on tomatoes. The prepared composite films have considerable potential for packaging applications. • The GEO Pickering emulsions stabilized by TOCN was successfully prepared. • The prepared starch-based composited film had good strength, hydrophobic property and antibacterial property. • The starch-based composited film with TOCN/GEO had a better storage effect on tomatoes.

Effect of pine, eucalyptus, and corn straw nanofibers on the structural properties of rice flour-based biodegradable films

The objective of this study was to develop biodegradable films produced from broken grains of rice (agro-industrial byproducts), sorbitol, and pectin, and to evaluate the influence of pine (PN), eucalyptus (EN), and corn straw (CN) nanofibers on the opacity, solubility, water vapor permeability, mechanical properties, and morphology of the films. Two simplex-centroid designs were used for the variables. Sorbitol and pectin interacted satisfactorily with rice starch, making the film more flexible and transparent. The cellulose nanofibers (50% PN, 50% EN, and 50% CN) increased the film opacity (2.8–3.35% μm −1 ) and decreased the water vapor permeability (0.035–0.037 g day −1 m −2 ) and water solubility (0.96–5.59%) of the rice flour-based films (10 g of rice flour, 1.5 g of pectin, and 19.5 mL of sorbitol solution at 70 g·mL −1 ). The PN, EN, and CN nanofibers improved the mechanical properties of the films: CN increased the elongation at break (6.32%) and hydrophobicity (72.12%); PN and EN increased the elasticity (20.50–25.31 MPa). The addition of combined nanofibers (PN+CN, EN +CN, and PN+EN) into the rice flour-based film (33:33:33) allows the film to be used as a coating and in food packaging. • Film characterization in terms of opacity, water solubility, and water vapor permeability. • Morphological analysis of nanofiber-containing films using SEM. • Mechanical property evaluation of films in terms of Young’s modulus and film puncture. • Discussion on film suitability as coating on fresh fruits.

Effect of W/O pre-emulsion prepared with different emulsifiers on the physicochemical properties of soy protein isolate-based emulsion films

The effects of incorporating a water-in-oil pre-emulsion based on different emulsifiers with similar hydrophilic-lipophilic balances on the physicochemical properties of soy protein isolate-based emulsion films were investigated. Confocal laser scanning microscopy images indicated that the oil droplet size in the polyglycerol polyricinoleate and lecithin pre-emulsions was larger than that in the glycerol monostearate, span, and sucrose ester pre-emulsions. By contrast, the oil droplet size in the film-forming emulsions had opposite orders. After drying, the polyglycerol polyricinoleate and lecithin emulsion films contained small and evenly distributed oil droplets and demonstrated a small difference of upper and lower surfaces in oil concentration and contact angle. The water vapor permeability of emulsion films prepared by polyglycerol polyricinoleate and lecithin pre-emulsion was 2.35 × 10−10 g m−1 s−1 Pa−1 and 2.32 × 10−10 g m−1 s−1 Pa−1, respectively, lower than that of other emulsion films. The control emulsion films had the highest tensile strength of 7.43 MPa, whereas polyglycerol polyricinoleate emulsion films had the lowest tensile strength of 4.87 MPa. Furthermore, the polyglycerol polyricinoleate emulsion films had the lowest glass transition temperature among the prepared emulsion films. This study concluded that the properties of film-forming emulsions could be affected by pre-emulsions based on different emulsifiers, resulting in different physicochemical properties of the emulsion films.

Design, Development And Evaluation Of Transdermal Drug Delivery System For Treatment Of Diabetes

The current research aims to formulate and evaluated Cinnamaldehyde transdermal patches to treat diabetes. A good penetration enhancer Oleic Acid, would improve drug delivery from various polymer-based transdermal patches. Transdermal patches of the matrix type were made by solvent casting techniques using various polymer PVP K30, HPMC K100, and solvent. All prepared formulations were tested for folding endurance, weight variation, thickness, drug content, moisture content, moisture loss, in vitro drug release and In- vivo studies. Batch TDP1 was optimised formula from all formulation batches shows zero order release for 24 hours, with a cumulative percentage of drug diffusion of 97.68% from 2cm2 patches. It has been determined that polymer concentration HPMC films showed better release which may be attributed to the reason of high water vapour permeability of HPMC films for enhancing diffusion rate of drug through rat skin, oleic acid were incorporated as permeation enhancers in the HPMC films since they showed better release. It allows for controlled drug release from the patch. Drug content of the patches was found to be more than 98%. Variations in flux and Diffusion Coefficient were observed among various formulations. The drug–polymer interaction results suggested no interaction between drug and polymers. The in vivo results revealed that the patches successfully prevented the hyperglycaemia and they were also effective on chronic application. The transdermal route exhibited negligible skin irritation and produced better improvement with all the tested in vivo parameters compared to oral administration.

Correlation between chain structures of corn starch and properties of its film prepared at different degrees of disorganization

This study investigated the relationship between the chain structure of corn starch and the properties of corn starch-based films formed with starch pastes with different degrees of disorganization (70, 80, and 90 °C). The degree of gelatinization, chain length distribution, amylose content, and molecular weight of the corn starch were determined by the water absorption index, ion chromatography, spectrophotometry, and gel chromatography, respectively. The thickness, surface roughness, solubility, water content, water vapor permeability, mechanical properties, and maximum thermal degradation rate of corn starch-based films formed with starch pastes with different degrees of disorganization were evaluated. The moisture content, thickness and surface roughness of films formed with the starch pastes decreased. At the same time, the solubility, elongation at break, water vapor permeability, and molecular weight distribution increased with increasing heat treatment temperature. The maximum thermal degradation rate and tensile strength of the corn starch-based films formed with the starch pastes decreased with increasing heat treatment temperature. The gradual decrease in the amylose content of corn starch-based films formed with starch paste with increasing heat treatment temperature led to a change in the performance of the corn starch-based films.