Advanced Materials Research Vol. 1060

Abstract: To better understand lipid-based implants applied to proteins, lysozyme was used as a model protein and was loaded into lipid-based implants in different contents. Cylindrical and spherical implants loaded with lysozyme presented a smooth surface. Protein loading efficiency decreased with increasing lysozyme loading. Lysozyme kept its activity after different implant preparation techniques. Drug release tremendously increased by increasing protein loading from 8.9 to 13.7% (w/w), for cylindrical implants. Lysozyme release was faster from cylindrical implants when compared with the spherical ones. Furthermore, by increasing the hydrophobicity of the lipid, protein release decreased. This study demonstrates the potential use of lipid-based implants for the controlled release of proteins.

Abstract: Lipid implants have been attracting attention in recent years. However, to better understand these systems, more fundamental studies are required. The objective of this work was to evaluate the effect of some formulation parameters, namely lipid and drug type, implant shape/surface area and lipid blend ratio, on drug release rate. The developed implants were cylindrical or spherical in shape with an even surface. Caffeine release from glycerol-trimyristate implant was very fast when compared with glycerol-tristerate matrix. The latter allowed a 4 month controlled release in contrast with glycerol-trimyristate matrix (~ 5 days). Caffeine and theophylline presented similar release rates, despite their different aqueous solubilities. In addition, different lipid blend ratios provided different release profiles for caffeine.

Abstract: Development of stable dry emulsion capable to self- reform into emulsion by reconstitution in water is presented. The major compositions of oil in water (o/w) emulsion were cold pressed-coconut oil (or virgin coconut oil from four different companies) as oil phase and water as phase containing an emulsifier [hydroxypropylmethylcellulose (HPMC)] and a densifier or solid [tapioca starch (T)]. Dry emulsions were prepared by placing liquid emulsion in condition at 60 °C. The percentage yield of dry emulsion was between 59-62%. After sieving, the most flowability data of dry emulsion granules were passable as a result of some oily parts appeared in particles. The moisture contents in dry emulsion granule were relatively low. The antioxidant activity of oil, primary emulsion (PE) and reconstitute emulsion (RE) were also investigated with Trolox as standard. It was found that the order of antioxidant activity of coconut oil as decrease as following: oil, emulsion and reconstitute emulsion respectively. After 2 freeze-thaw cycles, all reconstituted emulsions were shown to be unstable. The four different brands of virgin coconut oil showed no significant different physical and antioxidant properties of PE and RE. Thus, the process of making a virgin coconut oil dry emulsion might not be affected by any different sources of virgin coconut oil.

Abstract: Clerodendrum disparifolium is a Thai herbal medicine, which is used for the treatment of insect bites and sting reactions by applying finely crushed leaves to the inflamed area. However, this usage is inconvenient. The study aimed to develop gel-and cream-based formulations containing 0.5 %w/v of C. disparifolium extract, and evaluate their physicochemical properties. Different topical formulations were prepared using Carbopol 934 for gels and stearic acid for creams by varying their concentrations. The results showed that gel-based formulation containing Carbopol 934 in the range of 0.5-1.0 %w/w had good appearance, appropriate spreadability (7.30-8.70 cm) and viscosity (33,100-68,920 centipoise (cps)). The pH of gel-based formulation ranged from 6.01 to 6.11. For cream-based formulation containing 10-12 % w/w of stearic acid exhibited good physicochemical characteristics. The spreadability, viscosity and pH were 5.00-5.50 cm, 110,050-174,900 cps and 6.03-6.08, respectively. The results provided the suitable formulations, which should be continuously developed for large-scale pharmaceutical production.

Abstract: Presently, the low energy emulsification method; phase inversion temperature (PIT) method offers a convenient mean of nanoemulsion formation for the incorporation of fragile substances. The aim of the current study was to prepare coconut oil nanoemulsions using cremophor RH 40 as nonionic surfactant in the light of PIT method. The suitable composition of coconut oil, cremophor RH40 and water was investigated by construction of ternary phase diagram. The PIT of system can be adjusted to 75 °C by adding NaCl at the concentration of 6%(w/w). Stable translucent nanoemulsions with particle size in range of 20-100 nm and PDI<0.2 can be formed at the constituent proportions of 5%-30%(w/w), coconut oil, 10%-80%(w/w) cremophor RH40 and 5%-85%(w/w) NaCl solution of 6%(w/w). All formulations were stable for up to 2 months when stored at 4, 30 and 40 °C and protected from light.

Abstract: Recently, nanoparticulate system has been applied to deliver drug to colon because this system can increase drug absorption, prolong drug staying in gastrointestinal tract and also minimize chance of dose dumping effect. In this study, nanoparticles (NPs) developed for colonic drug delivery were fabricated via electrohydrodynamic atomization (EHDA) to find suitable formulation and preparation conditions. The NPs were prepared by dissolving prednisolone (model drug) and Eudragit^® S100 (EDS100) in methanol, ethanol, isopropanol, butanol and mixtures of ethanol with purified water in various drug/polymer weight ratio and polymer concentrations. After that, the prepared solution was injected using the EHDA machine. The preparation condition and the instrument parameters such as applied voltage, injected distance, feed rate, and drum collector rolling rate were delicately adjusted again to obtain blank and drug loaded NPs. The NPs papered from methanol offered spherical particles with diameter size of 422 nm. The products of isopropanol and butanol were shrinkage particles. The sprayed products were changed from particle to fiber when using the spraying solution prepared from high concentration of EDS100. More fiber product was obtained when high applied voltage (20kV) was utilized. Prednisolone loaded NPs were also fabricated by EHDA. SEM and zeta-potential results reveal that prednisolone was entrapped in the NPs. All the drug loaded NPs products were in spherical shape with average diameter size of 448.60-660.98 nm and the maximum drug encapsulation was 92.65%. From the preliminary result, this nanoparticulate system expresses possibility to fabricate specific colonic drug delivery.

Abstract: The aim of this study was to investigate the physicochemical characteristics of various viscosity grades of hydroxypropyl methylcellulose (HPMC) for mucoadhesive buccal films. The HPMC used in this study was K4M, K15M and K100M which their viscosity were 4000, 15000 and 100000 mPas respectively. Using HPMC as film forming base matrix, all intrinsic characteristics of each HPMC grade is required as basic knowledge for the development of mucoadhesive buccal films. To understand the primary essential parameters, surface free energy and contact angle of various HPMC grades were determined. Sessile drop technique was used in this study to determine contact angle of HPMC and surface free energy was then evaluated by using the Wu’s equation. The results showed that the increase in viscosity of HPMC film tended to decrease the polar force and total surface free energy but increased the contact angle. These parameters indicated that the hydrophilic character of HPMC was influenced by its viscosity. Our study suggested that the polar and dispersive force detected by sessile drop technique could be beneficial for the further design and development of mucoadhesive buccal films.

Abstract: The aim of this study was to investigate the antioxidant activities of chitosan acetate (CS-acetate), chitosan hydroxybenzotriazole (CS-HOBt), chitosan thiamine pyrophosphate (CS-TPP) and chitosan ethylenediaminetetraacetic acid (CS-EDTA) nanofiber mats. Chitosan was dissolved with hydroxybenzotriazole (HOBt), thiamine pyrophosphate (TPP) and ethylenediaminetetraacetic acid (EDTA) in distilled water. These chitosan aqueous salts were blended with polyvinyl alcohol (PVA) at volume ratio 30/70 chitosan salts/PVA and prepared to nanofibers via electrospinning process. The morphology of electrospun chitosan aqueous salts based nanofiber mats were observed under scanning electron microscope (SEM). The antioxidant activities were determined employing various established in vitro system such as superoxide, hydroxyl radicals scavenging and metal ion chelating compared with pure PVA nanofiber mats. The results exhibited that the electrospun chitosan aqueous salts based nanofiber mats showed the different antioxidant activity depended on salt forms. Among the salt forms, CS-acetate nanofiber mats showed the highest superoxide radical scavenging effect while CS-HOBt nanofiber mats (IC₅₀ = 7.53 mg/mL) showed the highest hydroxyl radical scavenging effect. For the metal ion chelating activity, CS-EDTA nanofiber mats showed the highest chelating activity (IC₅₀ = 1.07 mg/mL). In summary, the antioxidant chitosan aqueous salt based nanofiber mats have potential for use in pharmaceutical applications.

Abstract: Silver nanoparticles (AgNPs) are of considerable interest for medical application due to their antimicrobial activity. However, only a limited number of natural polymers have been reported as colloidal stabilizers for AgNPs. This study aimed to synthesize AgNPs using hydrocolloids, alginate and carrageenan, as stabilizers. Hydrocolloid-capped AgNPs were synthesized by two methods: M1, a reductive sodium borohydride (NaBH₄) method, and M2, a microwave assisted reduction method. The synthesized AgNPs were characterized for surface plasmon resonance (SPR), size, surface charge and morphology. From the results, AgNPs stabilized by alginate (al-AgNPs) and carrageenan (ca-AgNPs) were able to be synthesized by methods M1 and M2. The SPR absorption peak around 400 nm of AgNPs represented the formation of rather spherical particles. The AgNPs formed by method M1were narrower in size distribution than that of AgNPs formed by method M2. Laser doppler electrophoresis (LDE) showed negative surface charges of al-AgNPs and ca-AgNPs because the anionic hydrocolloid polymers consist of carboxylic acid (alginate) and sulfate (carrageenan). Conclusively, AgNPs can be successfully formed and stabilized by alginate and carrageenan. Hydrocolloid-capped AgNPs are stable due to the electrostatic repulsion and steric stabilization of such polymers.

Abstract: The purpose of this study was to evaluate the effect of modified coconut oil (MCO) on elasticity change of films prepared from shellac. The MCO was added into shellac solution and then cast to thin film. The film containing MCO from 0-30% w/w was then comparatively evaluated. The result indicated that MCO had an direct effect on mechanical properties of films. The percentage elongation was increased while the tensile strength was decreased, as increasing percentage of MCO, suggesting the reduced brittleness of film. The FTIR peak assigned to O-H and C-O stretching was also shift after incorporation of MCO. Therefore, the plasticization of shellac film might due to the interaction between hydroxyl group of glycerides in MCO and shellac molecules.