Advanced Materials Research Vol. 1060

Abstract: This study aimed to develop oral microemulsions (MEs) containing M. alba extract. The stability study of the extract incorporated in the ME was also included. First, pseudo-ternary phase diagrams were constructed using caprylic/capric triglyceride (oil), PEG-8 caprylic/capric glycerides (S), polyglyceryl-3 diisostearate (CoS). Propylene glycol (PG) was used as a cosolvent. Then, the formulations were chosen to incorporate MSE and subjected to stability testing at 4^o C, room temperature (RT) and 45^o C at 75% RH for 8 weeks. Physical stability of the formulations was assessed by visual observation on the precipitation, phase separation and cloud point. Chemical stability was determined by quantitative analysis of oxyresveratrol using high performance liquid chromatography (HPLC). The results showed that with increasing the ratio of S/CoS, the area of ME existing region in phase diagrams increased. The addition of PG into aqueous phase at ratio 1:1 slightly affected the formation of MEs. Physical stability was not affected by temperature but was influenced by the components of the formulations. However, degradation of the extract was affected by both temperature and components of the formulations. The extract was stable at 4^o C and RT. However, at 45^o C, it degraded about 16-57%, depending on the components of the formulations. The best ME formulation consisted of 10% caprylic/capric triglyceride, 80% PEG-8 caprylic/capric glycerides and polyglyceryl-3 diisostearate (4:1), and 10% water and PG (1:1).

Abstract: The main objective of this study was to fabricate biopolymer-based microbeads, providing enteric properties and controlled release of diclofenac sodium, using layer-by-layer technique. The calcium pectinate microbeads have been designed and coated with chitosan and pectin multilayers. Drug release was performed in simulate gastric fluid (pH 1.2) for 2 hours, followed by pH 6.8 buffer for 8 hours. The effects of chitosan concentration, number of layer and drying technique on drug release were investigated. The results showed that the calcium pectinate microbeads could be simply prepared by ionotropic gelation and then coated with chitosan and pectin solutions using layer-by-layer procedure. The diameter of the microbeads ranged from 800 to 1000 μm for air-dried samples and from 1 to 2 mm for freeze-dried samples. The freeze-dried microbeads had a rough surface and many pores inside, as observed by SEM. The microbeads coated with 4% chitosan/4% pectin revealed a slower drug release than those coated with 1% chitosan/4% pectin and demonstrated a controlled release pattern. Moreover, different drying techniques and numbers of layer also influenced drug release behavior of the prepared microbeads.

Abstract: The aim of research was to fabricate shellac-zein composite polymer-based matrix tablets by using theophylline as a model drug. The tablets were prepared by direct compression process. The initial weight and hardness of tablets were controlled within the range of 300±5 mg and 60±10 N, respectively. The tablets were annealed at 80 °C for 24 h and kept in the ambient temperature before evaluation. Drug release profile and kinetics of drug release in 0.1 N HCl and buffer pH 6.8 were investigated. The result showed that the annealing process and shellac:zein ratio, affected drug release characteristic in both media.The delayed released in acid medium of formulation containg shellac-zein composite polymer at the ratio from 30:70 was extended to over 120 min. In addition, the more sustained drug released in buffer was observed after increasing shellac:zein ratio. The good acid resistance of shellac and the swollen characteristic of zein in buffer might be a good explanation for the specific release. For the analysis of drug release data, drug release profiles were fitted into Higuchi model suggesting that the main mechanism of drug release from matrix tablets was super case II transport.

Abstract: Transdermal patch is a drug delivery system using a polymer for controlling the drug release. In this study, polysaccharides from aloe vera gel were used as polymer in transdermal patches because they are compatible, biodegradable, and safe to apply on skin without any side effect. Pentacyclic triterpenoids rich (asiatic acid, madecassic acid, asiaticoside and madecassoside) Centella asiatica extracts were added as active ingredients. Both polymer and active ingredients show pharmacological effects as wound healing. It was found that the optimized formulation contained polysaccharides from aloe vera gel blended with 20% glycerine and 15% sodium alginate calculated based on aloe vera mass could produce the good films. These films could be controlled with respect to physical properties thickness (0.509±0.015 mm), tensile strength (1.391±0.131 MPa), elongation at break (116.2±13.15%), peel strength (0.116±0.044 N), the highest swelling times (20 minutes), and the percentage of degradation at 30 minutes (51.57±5.96%). About 0.34 % centella extracts (57% pentacyclic triterpenoids) could be found in these films. After stability studies at 4, 25 and 45 °C for 10 weeks, films stored at 45 °C were loss of flexibility and brittleness that could not be further evaluated. While films stored at 4 and 25 °C were good physiochemical properties and stable as same as films base.

Abstract: The aim of this study was to investigate the modification of black glutinous rice starch (BGRS) as tablet filler. The black glutinous rice was treated with NaCl and NaOH to obtain BGRS. The native BGRS was modified by pregelatinizaion and prepared as co-composite and used as filler in tablet formulation compared with Starch 1500^®. Propranolol was used as a model drug. The properties of tablets including disintegration time were evaluated. Interestingly, the disintegration times of the native BGRS was less than 90s which was faster than Starch 1500^®. The results suggest that the native BGRS would be used in fast disintegrating tablets. While the disintegration times of pregelatinized BGRS was more than 30 min. Thus, the pregelatinized BGRS might be used for sustained release tablet. For the co-composite method, PVP K90 in the concentration of 1, 3, 5, 7 and 9 % w/w was incorporated with BGRS. The tablets of the co-composite producing by direct compression method were compared with tablets producing by wet granulation method using PVP K90 as binder. In concentration of 3% w/w PVP K90, the co-composite was comparable to wet granulation method in term of hardness and disintegration time. Thus, it could be used as direct compression filler in pharmaceutical field.

Abstract: In this study, three nanostructured lipid carriers (NLC) formulations comprised of varying ratios of lipid (Compritol^® 888 ATO) and oil (Labrafac^® CC) including 4:1, 3:2, and 2.5:2.5, were developed by high shear homogenization technique. The effect of different ratios on the physicochemical properties and release profiles of the formulations were investigated. Increasing the amount of liquid oil increased the particle size and zeta potential whereas decreased size distribution of the blank and curcumin loaded NLC. However, the entrapment efficacy and loading capacity of the NLC for curcumin were not increased following such ratios. The different ratios were not influence on the sequence of sustained release of curcumin from the NLC over 60 h. Moreover, the amorphous curcumin and crystalline behavior of the optimized NLC were characterized by DSC and XRD techniques. Thus, the effect of the proportions of solid lipid and liquid oil in the formulations should be considered for development of suitable NLC system for oral curcumin delivery.

Abstract: In situ gel, a new concept of medical product for oral applications was developed using Poloxamer 407 (P) and Carbopol 934 (C) which are thermo-and pH-sensitive sol-gel polymers, respectively. The formulations were evaluated for the physical appearance, pH, viscosity, sol-gel temperature, gel strength and buccal mucoadhesive (adhesion to porcine buccal mucosa). Benzalkonium chloride (BzCl) 0.1% w/v was added in the suitable formulations as a model drug. Formulations containing 20% P (pH = 7.1) and 20% P + 0.6% C (pH = 5.0) showed good physical appearances which turned to gels in buccal conditions. Their mucoadhesive force to porcine buccal mucosa were higher than formulations containing 10 and 15 % P (p<0.05). The present of 0.6 % C in the formulation did not affect gel strength but tended to increase mucoadhesive properties. The release of BzCl from the formulations was performed using Franz diffusion cell at 37°C for 1 hour. There were no different in drug release from both formulations (p<0.05), the amount of drug release was 11.7% ± 4.4 and 10.9% ± 0.8, respectively. In conclusion, formulation containing 20% P and 0.6% C has revealed the most suitable properties as in situ gel for buccal mucosa applications, the release of BzCl was 10.9% ± 0.8 within 1 hour.

Abstract: This study aimed to develop green microemulsions (MEs) for loading coenzyme Q10 (CoQ10). Decylglucoside, a surfactant in the group of alkyl polyglycosides (APG), was used in the formulations since it is biodegradable and non-ionic, leading to low toxic products and friendly properties to the environment. Two blank MEs, i.e., M1 and M2 were prepared by simple mixing dicaprylyl ether, decylglucoside, sorbotan monolaurate and water in the concentrations of 70%, 2.5%, 22.5% and 5%, respectively for M1 and 60%, 6%, 24% and 10%, respectively for M2. Afterwards, M1 and M2 were incorporated with 5% CoQ10 to obtained QM1 and QM2, respectively. All samples were studied for physicochemical properties and stability under accelerated condition. It was found that they were transparence and absence of liquid crystals. Their rheological profiles indicated low viscosity and Newtonian flow. After stability test by freeze thaw for 5 cycles, physicochemical properties of M1, M2, QM1 and QM2 were not obviously different from those at the initial. In addition, more than 97% of label amount of CoQ10 were found in both QM1 and QM2 after stability study. The results indicated that the investigated decylglucoside MEs were suitable systems for incorporation with CoQ10.

Abstract: This study aimed to develop the preparation process of stable gelatin beads for drug loading. Gelatin beads were prepared by either ionotropic gelation or emulsification techniques. Hardening of gelatin beads were done by both cooling and chemical treatments. For ionotropic gelation techniques, aqueous gelatin solution was continuously dropped into cool calcium chloride (CaCl₂) or sodium tripolyphosphate (TPP) solution. However, the stable bead particles could not be formed. For emulsification techniques, water in oil (w/o) system was performed using aqueous gelatin solution as dispersed phase and cool soybean oil as dispersion medium, and glutaraldehyde (GAL) might also be used as chemical crosslinking agent. Gelatin type, amount of GAL, and crosslinking time slightly affected the characters of beads formation. Propranolol HCl could be loaded in gelatin beads.

Abstract: The aim of this study was to prepare matrix beads made of enteric polymer, Eudragit^® L, metronidazole and various amounts of cetyl alcohol (0, 0.1 and 1%). Eudragit^® L, metronidazole and cetyl alcohol were dissolved in acetone and then extruded into dichloromethane. The influence of amount of cetyl alcohol on floating and drug release behavior of matrix beads of Eudragit^® L was investigated. The results showed that, after extruding, cetyl alcohol dissolved out from the beads already formed, resulting in a porous structure. Thus, the beads can float in simulated gastric fluid for more than 8 hours. Different amounts of cetyl alcohol had a slight effect on the drug release. However, the increased amount of cetyl alcohol in the formulations significantly sustained the drug release while the beads remained floating. The results suggest that Eudragit^® L beads could be used as a carrier for intragastric floating drug delivery.