Unveiling the Molecular Dynamics, Anticancer Activity, and Stability of Spearmint Oil Nanoemulsions with Triglycerides.

Although spearmint oil (SMO) has various pharmacological properties, especially for cancer treatment, its low water solubility results in poor bioavailability. This limits its application as a medicine. One possible solution is to the use of SMO in the form of nanoemulsion, which has already been shown to have anticancer effects. However, the mechanism of SMO nanoemulsion formation remains unclear. The objective of this study was to use molecular dynamics (MD) for clarifying the formation of SMO nanoemulsion with triglycerides (trilaurin, tripalmitin, and triolein) and Cremophor RH40 (PCO40). Nanoemulsions with different SMO:triglyceride ratios and triglyceride types were prepared and analyzed for anticancer activity, droplet size, droplet morphology, and stability. Despite switching the type of carrier oil, SMO nanoemulsions retained strong anticancer effects. A ratio of 80SMO:20triglycerides produced the smallest droplets (<100 nm) and exhibited excellent physical stability after a temperature cycling test. MD simulations showed that polyoxyethylenes of PCO40 are located at the water interface, stabilizing the emulsion structure in an egglike layer. Droplet size correlated with triglyceride concentration, which was consistent with the experimental findings. Decreasing triglyceride content, except for the 90SMO:10triglyceride ratio, led to a decrease in droplet sizes. Hydrogen bond analysis identified interactions between triglyceride-PCO40 and carvone-PCO40. Geometry analysis showed PCO40 had an "L-like" shape, which maximizes the hydrophilic interfaces. These findings highlight the value of MD simulations in understanding the formation mechanism of SMO and triglyceride nanoemulsions. In addition, it might also be beneficial to use MD simulations before the experiment to select the potential composition for nanoemulsions, especially essential oil nanoemulsions.

Development and Evaluation of a Stable Oil-in-Water Emulsion with High Ostrich Oil Concentration for Skincare Applications.

This study investigates the development of an oil-in-water (O/W) emulsion enriched with a high concentration of ostrich oil, recognized for its abundant content of oleic acid (34.60 ± 0.01%), tailored for skincare applications. Using Span and Tween emulsifiers, we formulated an optimized emulsion with 20% w/w ostrich oil and a 15% w/w blend of Span 20 and Tween 80. This formulation, achieved via homogenization at 3800 rpm for 5 min, yielded the smallest droplet size (5.01 ± 0.43 µm) alongside an appropriate zeta potential (-32.22 mV). Our investigation into the influence of Span and Tween concentrations, types, and ratios on the stability of 20% w/w ostrich oil emulsions, maintaining a hydrophile-lipophile balance (HLB) of 5.5, consistently demonstrated the superior stability of the optimized emulsion across various formulations. Cytotoxicity assessments on human dermal fibroblasts affirmed the safety of the emulsion. Notably, the emulsion exhibited a 52.20 ± 2.01% inhibition of linoleic acid oxidation, surpassing the 44.70 ± 1.94% inhibition observed for ostrich oil alone. Moreover, it demonstrated a superior inhibitory zone against Staphylococcus aureus (12.32 ± 0.19 mm), compared to the 6.12 ± 0.15 mm observed for ostrich oil alone, highlighting its enhanced antioxidant and antibacterial properties and strengthening its potential for skincare applications. The optimized emulsion also demonstrates the release of 78.16 ± 1.22% of oleic acid across the cellulose acetate membrane after 180 min of study time. This successful release of oleic acid further enhances the overall efficacy and versatility of the optimized emulsion. Stability assessments, conducted over 6 months at different temperatures (4 °C, 25 °C, 45 °C), confirmed the emulsion's sustained physicochemical and microbial stability, supporting its promise for topical applications. Despite minor fluctuations in acid values (AV) and peroxide values (PV), the results remained within the acceptable limits. This research elucidates the crucial role of emulsification in optimizing the efficacy and stability of ostrich oil in skincare formulations, providing valuable insights for practical applications where stability is paramount.

Fabrication and Optimization of Electrospun Shellac Fibers Loaded with Senna alata Leaf Extract.

Single-fluid electrospinning creates nanofibers from molten polymer solutions with active ingredients. This study utilized a combination of a fractional factorial design and a Box-Behnken design to examine crucial factors among a multitude of parameters and to optimize the electrospinning conditions that impact fiber mats' morphology and the entrapment efficiency of Senna alata leaf extract. The findings indicated that the shellac content had the greatest impact on both fiber diameter and bead formation. The optimum electrospinning conditions were identified as a voltage of 24 kV, a solution feed rate of 0.8 mL/h, and a shellac-extract ratio of 38.5:3.8. These conditions produced nanosized fibers with a diameter of 306 nm, a low bead-to-fiber ratio of 0.29, and an extract entrapment efficiency of 96% within the fibers. The biphasic profile of the optimized nanofibers was confirmed with an in vitro release study. This profile consisted of an initial burst release of 88% within the first hour, which was succeeded by a sustained release pattern surpassing 90% for the next 12 h, as predicted with zero-order release kinetics. The optimized nanofibers demonstrated antimicrobial efficacy against diverse pathogens, suggesting promising applications in wound dressings and protective textiles.

Advances in Natural Product Extraction Techniques, Electrospun Fiber Fabrication, and the Integration of Experimental Design: A Comprehensive Review.

The present review explores the growing interest in the techniques employed for extracting natural products. It emphasizes the limitations of conventional extraction methods and introduces superior non-conventional alternatives, particularly ultrasound-assisted extraction. Characterization and quantification of bioactive constituents through chromatography coupled with spectroscopy are recommended, while the importance of method development and validation for biomarker quantification is underscored. At present, electrospun fibers provide a versatile platform for incorporating bioactive extracts and have extensive potential in diverse fields due to their unique structural and functional characteristics. Thus, the review also highlights the fabrication of electrospun fibers containing bioactive extracts. The preparation of biologically active extracts under optimal conditions, including the selection of safe solvents and cost-effective equipment, holds promising potential in the pharmaceutical, food, and cosmetic industries. Integration of experimental design into extraction procedures and formulation development is essential for the efficient production of health products. The review explores potential applications of encapsulating natural product extracts in electrospun fibers, such as wound healing, antibacterial activity, and antioxidant properties, while acknowledging the need for further exploration and optimization in this field. The findings discussed in this review are anticipated to serve as a valuable resource for the processing industry, enabling the utilization of affordable and environmentally friendly, natural, and raw materials.

Preparation of Bioactive De-Chlorophyll Rhein-Rich Senna alata Extract.

Senna alata leaves display various biological activities as a result of their rhein and phenolic composition. The objective of this study was to develop bioactive de-chlorophyll rhein-rich S. alata extracts. The rhein content was quantified using a validated high-performance liquid chromatography-diode array detection (HPLC-DAD) method. The best process parameters for maximizing rhein were established using ultrasound-assisted extraction (UAE). The optimal conditions for the parameters were determined using the Box-Behnken design (BBD); 95% v/v ethanol was used as the extraction solvent at 59.52 °C for 18.4 min with a solvent-to-solid ratio of 25.48:1 (mL/g) to obtain the predicted value of rhein at 10.44 mg/g extract. However, the color of the rhein-rich extract remained dark brown. For the removal of chlorophyll, liquid-liquid extraction with vegetable oils and adsorption with bleaching agents were employed. The bleaching agents were significantly more effective at removing chlorophyll and had less of an effect on the reduction in rhein content than vegetable oils. The presence of rhein and phenolics in the de-chlorophyll extracts might be responsible for their antioxidant, anti-inflammatory, and antibacterial activities. These findings indicate that rhein-rich extract and its de-chlorophyll extracts possess sufficient biological activities for the further development of cosmeceuticals and pharmaceuticals.

Optimization of Ultrasound-Assisted Extraction of Yields and Total Methoxyflavone Contents from Kaempferia parviflora Rhizomes.

The major bioactive components of Kaempferia parviflora (KP) rhizomes, 3,5,7,3',4'-pentamethoxyflavone (PMF), 5,7-dimethoxyflavone (DMF), and 5,7,4'-trimethoxyflavone (TMF), were chosen as the quantitative and qualitative markers for this plant material. In order to extract bioactive components (total methoxyflavones) from KP rhizomes, ultrasound-assisted extraction (UAE) was proposed as part of this study. Plackett-Burman design (PBD) and Box-Behnken design (BBD) were utilized to optimize the effects of UAE on extraction yields and total methoxyflavone contents in KP rhizomes. First, PBD was utilized to determine the effect of five independent variables on total yields and total methoxyflavone contents. The results indicated that the concentration of the extracting solvent (ethanol), the extraction time, and the ratio of solvent to solid were significant independent terms. Subsequently, BBD with three-level factorial experiments was used to optimize the crucial variables. It was discovered that the concentration of ethanol was the most influential variable on yields and total methoxyflavone contents. Optimum conditions for extraction yield were ethanol concentration (54.24% v/v), extraction time (25.25 min), and solvent-to-solid ratio (49.63 mL/g), while optimum conditions for total methoxyflavone content were ethanol concentration (95.00% v/v), extraction time (15.99 min), and solvent-to-solid ratio (50.00 mL/g). The relationship between the experimental and theoretical values was perfect, which proved that the regression models used were correct and that PBD and BBD were used to optimize the conditions in the UAE to obtain the highest yield and total methoxyflavone content in the KP rhizomes.

Impact of Fixed Oil on Ostwald Ripening of Anti-Oral Cancer Nanoemulsions Loaded with Amomum kravanh Essential Oil.

Recently, essential oil from Amomum kravanh (AMO) was reported to exert anti-oral cancer effects. Although it was more effective after being loaded into nanoemulsions, AMO without an Ostwald ripening inhibitor was unable to form stable nanoemulsions because of the Ostwald ripening phenomenon. In this study, we examined the influence of Ostwald ripening inhibitors, such as fixed oils and polyethylene glycol 4000 (PEG 4000), on nanoemulsion properties prepared by a phase inversion temperature method. Several fixed oils, including virgin coconut oil (VCO), palm oil (PMO), olive oil (OLO), and PEG 4000, were evaluated, and their Ostwald ripening inhibitory effects were compared. The results suggest that the type and ratio of AMO:fixed oils influence the formation and characteristics of nanoemulsions. PEG 4000 was unable to produce nanoemulsions; however, stable nanoemulsions with small droplet sizes were observed in preparations containing OLO and VCO at an AMO:fixed oil ratio of 80:20, which may be the result of specific molecular interactions among the components. Using an MTT assay, we demonstrated that the AMO:OLO (80:20) nanoemulsion produced the most significant cytotoxic effect on oral cancer cells with a percentage of 99.68 ± 0.56%. Furthermore, the AMO:OLO 80:20 nanoemulsion inhibits metastasis and induces oral cancer cell death through the intrinsic apoptosis pathway. In conclusion, AMO nanoemulsion with anti-oral cancer activity was successfully produced by varying the amount and type of fixed oils. In the future, this discovery may lead to the development of stable nanoemulsions employing additional volatile oils.

Monolaurin-Loaded Gel-Like Microemulsion for Oropharyngeal Candidiasis Treatment: Structural Characterisation and In Vitro Antifungal Property.

Recently, monolaurin (ML) has received great interest due to its possible use as an alternative antifungal. However, the limited water solubility of ML is still a major obstacle to its formulation and application. Gel-like microemulsions are one of the promising carriers for low-water-solubility substances due to both the advantages of gels and microemulsions and may be applied for ML. In this study, ML was incorporated into gel-like microemulsions and evaluated for its physicochemical and antifungal properties. The results indicated that the properties of gel-like microemulsion changed after the incorporation of ML, suggesting that ML can induce the transition of internal structure. When simulating the oral cavity environment, changes in the microstructure were observed and depended on the times of dilution. The lamellar structure was formed at 1.5-2 times dilution. However, this structure was disrupted after dilution five times or more. The structural change following dilution was associated with the release profiles. After contacting the formulations with the medium, ML was promptly released, with the majority of ML being released within 2 h. Regarding the antifungal assay, the ML-loaded gel-like microemulsions decreased the survival of Candida albicans within 3 h, although ML was immediately released, suggesting that the ML-loaded in oil droplets required time to permeate through the fungal cell wall. Additionally, the gel-like microemulsions possessed acceptable stability after the temperature cycling test. Therefore, gel-like microemulsions can be a possible carrier for ML loading, and ML-loaded gel-like microemulsions may be applied as an alternative antifungal preparation in the future. Graphical abstract.

Fabrication, Optimization, and Characterization of Antibacterial Electrospun Shellac Fibers Loaded with Kaempferia parviflora Extract.

This study aimed to develop a Kaempferia parviflora (KP) extract based on electrospun shellac fibers capable of transporting methoxyflavones. This study used a Box-Behnken design to determine the optimal production parameters that influence the fiber diameter and bead-to-fiber ratio responses. The optimization step produced fibers with a small diameter (574 nm) and a lower bead-to-fiber ratio (0.48 beads per fiber) by combining 37.25% w/w shellac and 1.50% w/w KP extract with a solution feed rate of 0.8 mL/h and an electrical voltage of 18 kV. The KP extract was found to be dispersed throughout the electrospun shellac fibers during the characterization study. The results were highly correlated with the theoretical values, indicating that the regression models used to predict the response variables were adequate. A study of in vitro dissolution confirmed that KP extract-loaded electrospun shellac fibers could produce a sustained-release profile within 10 h. Additionally, KP-infused shellac fibers demonstrated antibacterial activity against Staphylococcus aureus. This KP loading method combined with shellac properties provided a new delivery system and could be used to explore novel biomedical materials.

Students' Perspectives and Achievements toward Online Teaching of Medicinal Chemistry Courses at Pharmacy School in Thailand During the COVID-19 Pandemic.

This communication was to share the efforts made in developing the fully online courses in medicinal chemistry during the educational disruption due to the coronavirus disease 2019 (COVID-19) pandemic. In the academic year 2020, the online course was implemented for the first time at the Faculty of Pharmacy, Silpakorn University, Thailand. Various online teaching strategies were integrated, raising the question of whether the developed online courses would deliver similar learning outcomes to the traditional classroom. At the end of each semester, the teaching assessment report was conducted and evaluated in 4 parts: part 1, evaluation of lecturer; part 2, student's self-evaluation; part 3, learning outcome development after studying the course; part 4, appropriateness of class environment and equipment. Overall, student responses toward parts 1-3 in the online class were as satisfactory as those in the previous on-site class. Lower scores toward part 4 were observed in the online class. In addition, student performance in terms of grade distributions between the on-site and online classes was different. On-site students earned the highest proportion of A grades, whereas online students earned a higher proportion of B+'s to F's. While the pandemic persists and the need for online courses remains, we hope that this communication will provide some educational insight and strategies to help in the ongoing efforts to adapt and establish more successful online courses.

Phytochemical analysis of baby corn silk extracts.

BACKGROUND: Baby corn silk extract can be used as an antioxidant dietary supplement. However, insufficient data exists for this extract to guarantee its quality, efficacy and safety. OBJECTIVE: To determine phytochemical constituents, contents of phenolics and flavonoids, antioxidant activities, heavy metal concentrations, and microbial contamination of baby corn silk extracts. MATERIAL AND METHODS: Baby corn silks including Pacific 271 and Zeba SG 17 hybrids were individually extracted with 40% v/v ethanol and distilled water to obtain Pacific 271 ethanol extract (PE), Zeba SG 17 ethanol extract (ZE), Pacific 271 aqueous extract (PA), and Zeba SG 17 aqueous extract (ZA). The analysis of phytochemical constituents was carried out using phytochemical tests, TLC screening, UV-visible, FTIR, and 1H NMR experiments. The contents of phenolics and flavonoids were determined using the modified Folin-Ciocalteu and aluminium chloride colorimetric procedures, respectively. Antioxidant activities were investigated using DPPH and FRAP assays. The concentrations of heavy metals were analyzed by ICP-MS. Microbial enumeration tests were carried out according to the United States Pharmacopeia (USP) 41. RESULTS: PE and ZE were composed of flavonoids, tannins, terpenoids, and steroids while PA and ZA contained flavonoids and tannins. PE and ZE exhibited higher total phenolic and flavonoid contents and significantly stronger antioxidant activities than PA and ZA. All extracts conformed to the microbiological and heavy metal requirements according to Association of South East Asian Nations (ASEAN) guidelines. CONCLUSION: PE and ZE were considered appropriate to use as natural extracts of phenolics and flavonoids with antioxidant activities and safety.

Design and characterisation of electrospun shellac-polyvinylpyrrolidone blended micro/nanofibres loaded with monolaurin for application in wound healing.

Due to their ultrafine network structures, electrospun nanofibres have been potentially used for wound application. In order to develop a desired wound dressing material, shellac (SHL) was blended with polyvinyl pyrrolidone (PVP). Monolaurin (ML), which is a natural antimicrobial lipid, was incorporated into the SHL-PVP blended fibres to prevent delayed wound healing resulting from microbial infection. A full factorial design with three replicated centre points was employed in order to determine the main and interaction effects of various factors including SHL ratio in SHL-PVP blended solution, ML content and applied voltage on the multiple responses such as morphology, surface wettability, absorbency and mechanical properties. According to the results, an increase in the PVP content could lead to a significant increase in tensile strength and elongation. In addition, the presence of PVP contributed to an improvement in the drug loading capacity and dissolution rate. The fabricated fibres loaded with ML exhibited an excellent activity against Staphylococcus aureus and Candida albicans, and also provided an enhanced ability in the cell adhesion. Therefore, SHL-PVP blended fibres loaded with ML might be effectively used for application in wound healing.

Optimization and comparison of GC-FID and HPLC-ELSD methods for determination of lauric acid, mono-, di-, and trilaurins in modified coconut oil.

Modified coconut oil (MCO) obtained from the glycerolysis of virgin coconut oil (VCO) and glycerol under various conditions should have different amounts of bioactive fatty acids (FAs) and acylglycerols (AGs). Methods were developed to analyze lauric acid (LA), monolaurin (ML), dilaurin (DL), and trilaurin (TL) in MCO samples using gas chromatography - flame ionization detector (GC-FID) and high performance liquid chromatography - evaporative light scattering detector (HPLC-ELSD). The purpose of this research is to optimize and compare GC-FID and HPLC-ELSD methods for determination of LA, ML, DL, and TL in MCO samples. All the standard curves exhibited good linearity (R2 ≥ 0.9995), except for that of LA analyzed by HPLC-ELSD (R2 = 0.9971). The limits of detection (LODs) and quantification (LOQs) were found to be in the range of 0.033-0.260 mg/ml and 0.099-0.789 mg/ml for the GC-FID method and 0.040-0.421 mg/ml and 0.122-1.277 mg/ml for the HPLC-ELSD method, respectively. The GC-FID method (LOD ≤ 0.033 mg/ml) was more sensitive than HPLC-ELSD method (LOD ≤ 0.421 mg/ml) and showed satisfactory recoveries for LA analysis while HPLC-ELSD method (LOD ≤ 0.040 mg/ml) was more sensitive than GC-FID method (LOD ≤ 0.260 mg/ml) and exhibited acceptable recoveries for TL analysis. Both methods were applied to determine the MCO samples produced under varied conditions for glycerolysis. The results revealed that the developed GC-FID method is suitable for the quantification of LA, ML, and DL while the developed HPLC-ELSD method is appropriate for the determination of ML, DL, and TL. Both developed GC-FID and HPLC-ELSD methods produced reproducible results for the determination of LA, ML, DL, and TL in MCO samples.

The effect of surfactant on the physical properties of coconut oil nanoemulsions.

The aim of this study was to develop the water compatible form of coconut oil through nano-emulsification. The effect of different types and amounts of surfactants on the physical characteristics of nanoemulsions containing coconut oil was investigated. Coconut oil nanoemulsions containing varied amounts of surfactants including polyethylene glycol octyl phenyl ether (PGO), polyoxyethylene sorbitan monostearate (POS), polyethylene glycol hydrogenated castor oil (PHC), sodium lauryl sulfate (SLS) and poloxamer 407 (PLX) were formulated and comparatively evaluated for their physical properties. The results showed that the coconut oil nanoemulsions using PGO, POS and PHC as surfactants exhibited low percent creaming index indicating excellent stability, while those containing SLS and PLX demonstrated the higher percent creaming index suggesting lesser physical stability. The droplet sizes of nanoemulsions consisting of 5% (w/w) PGO, POS and PHC were 22.843, 4.458 and 0.162 µm, respectively. Thus, coconut oil nanoemulsions with the smallest size could be obtained when PHC was applied. Furthermore, the droplet size of nanoemulsions decreased from 33 µm to less than 200 nm with an increase in the amount of PHC from 1% to 10% (w/w). Additionally, the properties of coconut oil based nanoemulsions containing PHC were not changed through temperature cycling test. From these results, it was suggested that the fabrication of stable coconut oil nanoemulsions with small particle size could be easily achieved by using 5% (w/w) PHC as a surfactant. The knowledge gained from the study might provide the basic guideline for the fabrication of stable nanoemulsions for food, cosmetic and pharmaceutical fields in the future.

Formulation and evaluation of gels containing coconut kernel extract for topical application.

The biological activity of coconut (Cocos nucifera L.) extracts from its kernels and various parts was reported by many previous studies, it is therefore believable that the extracts of its kernels might show some activities in topical formulations. Among several kernel extracts, the TC06 extract prepared by soaking the steamed coconut kernels in hot water showed the highest total phenolic content (6.98 ±â€¯0.30 mg GAE/g extract) and the strongest antioxidant activity as determined using FRAP and DPPH methods with a reducing power value of 4.12 ±â€¯0.16 mg AAE/g of extract and an SC50 value of 2.38 ±â€¯0.14 mg/ml, respectively. In addition, this extract did not display any cytotoxic effects in the concentration range of 50-3200 µg/ml. Meanwhile, it revealed cytoprotective effects against t-BHP-induced cytotoxicity in HaCaT cells at concentrations higher than 400 µg/ml. The results of phytochemical investigations including a chemical color test, TLC, 1H NMR and FTIR suggested that the TC06 extract was mainly composed of flavonoids and terpenoids. Furthermore, the concentrations of heavy metals including As, Cd, Hg, and Pb in the TC06 extract were below permissible limits. According to the solubility, the TC06 extract was incorporated into gels using Carbopol Ultrez 21 as a gelling agent. The formulated gel containing 3% (w/w) TC06 extract was stable at 4 °C and 25 °C with 75% RH throughout the storage period. It was found that the Carbopol Ultrez 21-based hydroalcoholic gel containing an aqueous extract of coconut kernels exhibited antioxidant activities in the two assays and showed a sufficient consistency, a pleasing color, and a non-oily perception during the period of observation.

Fabrication and characterization of spearmint oil loaded nanoemulsions as cytotoxic agents against oral cancer cell.

Spearmint oil (SMO), a commonly used essential oil for oral care products, possesses various interesting functions, especially for anticancer property. However, the application of SMO for cancer treatment is limited due to water insoluble. In the present study, nanoemulsions, which have been widely accepted as dosage forms for poorly water-soluble drugs, were selected as candidate carriers for SMO to inhibit oral cancer cell. The nanoemulsions were fabricated using phase inversion temperature method. The factors affecting formation and properties of nanoemulsions including type and amount of surfactants, oil loading and ratio of SMO to virgin coconut oil (VCO) were investigated. Among the surfactants used, the nanoemulsions containing polyoxyethylene castor oil derivatives (Kolliphor®EL; PCO35, Cremophor®RH40; PCO40, Eumulgin®CO60; PCO60) and polyoxyethylene sorbitan fatty acid esters (PSF80) showed 100% creaming after temperature cycling test indicating excellent physical stability while those containing PCO40 demonstrated more transparency and better physical stability. With an increasing amount of PCO40, the droplet size tended to decrease and was in the nano-size range (<1000 nm) after increasing to more than 5% (w/w). SMO-VCO loading also influenced on the droplet size. At 5% (w/w) PCO40, the maximum SMO-VCO loading of 25% (w/w) to attain nanoemulsions was observed. Moreover, the composition of oils had an impact on size of emulsions. The transparent nanoemulsions were only prepared in the range of SMO-VCO from 40:60 to 80:20, suggesting the optimum ratio of SMO to surfactant and the composition of oils were the critical factors for formation of nanoemulsions. NMR study disclosed that the interaction between PCO40 with both VCO and SMO should be a possible stabilization mechanism. Furthermore, the SMO-VCO nanoemulsions exhibited significant cytotoxic effect against oral carcinoma (KON) cell line using MTT assay. The finding, therefore, revealed the good feasibility of SMO-VCO nanoemulsions as novel carriers for treating of oral cancer.

Design and characterization of monolaurin loaded electrospun shellac nanofibers with antimicrobial activity.

The aim of this study was to elucidate the optimized fabrication factors influencing the formation and properties of shellac (SHL) nanofibers loaded with an antimicrobial monolaurin (ML). The main and interaction effects of formulation and process parameters including SHL content (35%-40% w/w), ML content (1%-3% w/w), applied voltage (9-27 kV) and flow rate (0.4-1.2 ml/h) on the characteristic of nanofibers were investigated through a total of 19 experiments based on a full factorial design with three replicated center points. As a result, the SHL content was the major parameter affecting fiber diameter. Another response result revealed that the SHL content would be also the most significant negative impact on amount of beads. An increase in the concentration of SHL leaded to a reduction in the amount of beads. From the results of characterization study, it was proved that ML might be entrapped between the chains of SHL during the electrospinning process exhibiting an excellent encapsulation. According to the response surface area, small (~488 nm) and beadless (~0.48) fibers were obtained with the SHL and ML contents of 37.5% and 1.1% w/w respectively, at the applied voltage of 18 kV and the flow rate of 0.8 ml/h. In addition, the results of the kill-kinetic studies showed that SHL nanofibers loaded with ML exhibited an excellent antibacterial activity against Staphylococcus aureus, while Escherichia coli was less affected due to the hydrophilic structure of the its outer membrane. ML also exerted an antifungal activity by reducing the number of Candida albicans colonies. Based on their structural and antimicrobial properties, SHL nanofibers containing ML could be potentially used as a medicated dressing for wound treatment.

Formation of shellac succinate having improved enteric film properties through dry media reaction.

The aim of this study was to improve enteric properties of shellac by the formation of succinate derivative through dry media reaction. Shellac and succinic anhydride were mixed and then co-ground by planetary ball mill. The ground mixture was then activated by heating for various times and washed for removal of excess succinic anhydride. The ground mixtures and the heat-activated mixtures were characterized by physical and chemical tests, including acid value, FTIR spectroscopy, (1)H NMR and (13)C NMR spectroscopy, thermal analysis and film properties. The results demonstrated that acid values of heat-activated shellac mixtures increased with the increase of annealing time, suggesting the presence of carboxylic acid moieties of succinate at shellac molecules. The results were in good agreement with the DSC thermograms. The melting peak of shellac disappeared after heating, while melting peak of succinic anhydride gradually decreased, suggesting the utilization of succinic anhydride for the esterification. The shellac succinate formation was also confirmed by (1)H NMR and (13)C NMR spectroscopies. Film prepared from shellac succinate showed improved solubility, especially at the pH of small intestine (5.8-6.7), as compared to native shellac. The shellac succinate film also demonstrated better mechanical property, in terms of increased flexibility. In conclusion, solid-state formation of shellac succinate ester, which had improved enteric properties, was easily accomplished under the concept of "green approach".

Modulation of drug release kinetics of shellac-based matrix tablets by in-situ polymerization through annealing process.

A new oral-controlled release matrix tablet based on shellac polymer was designed and developed, using metronidazole (MZ) as a model drug. The shellac-based matrix tablets were prepared by wet granulation using different amounts of shellac and lactose. The effect of annealing temperature and pH of medium on drug release from matrix tablets was investigated. The increased amount of shellac and increased annealing temperature significantly affected the physical properties (i.e., tablet hardness and tablet disintegration) and MZ release from the matrix tablets. The in-situ polymerization played a major role on the changes in shellac properties during annealing process. Though the shellac did not dissolve in acid medium, the MZ release in 0.1N HCl was faster than in pH 7.3 buffer, resulting from a higher solubility of MZ in acid medium. The modulation of MZ release kinetics from shellac-based matrix tablets could be accomplished by varying the amount of shellac or annealing temperature. The release kinetics was shifted from relaxation-controlled release to diffusion-controlled release when the amount of shellac or the annealing temperature was increased.

Enhanced enteric properties and stability of shellac films through composite salts formation.

The objective of this study was to improve the properties of shellac by composite salts formation. The shellac samples were prepared in various salt forms by dissolving them with 2-amino-2-methyl-1-propanol (AMP) and ammonium hydroxide (AMN) at various ratios of AMP:AMN. The results demonstrated that aqueous solubility of the shellac salts was improved as the ratio of AMP:AMN increased. The absorbance ratio of the FTIR peaks assigned to CO stretching of carboxylate and carboxylic acid (ABS1556/ABS1716) was increased with the increase of the AMP fraction, suggesting that the solubility enhancement was due to more ionization of AMP salts. Moisture adsorption studies indicated that shellac salts were more hygroscopic as AMP content increased. After storage at 40 degrees C, 75% RH, the acid value and insoluble solid of AMP salts were relatively constant even after storage of up to 180 days, suggesting that AMP should protect polymerization. The ABS1556/ABS1716 values of the shellac salts were rapidly decreased after storage, especially for those consisting of a high percentage of AMN. Thus, AMP should bind much tighter at the carboxylate binding site as compared with AMN, resulting in more solubility and stability. In conclusion, optimized shellac properties could be easily accomplished by composite salts formation.