Ray Neng Chen

Development of swelling/floating gastroretentive drug delivery system based on a combination of hydroxyethyl cellulose and sodium carboxymethyl cellulose for Losartan and its clinical relevance in healthy volunteers with CYP2C9 polymorphism.

The aim of this study was to develop an optimal gastroretentive drug delivery system (GRDDS) for administering Losartan. Additionally, the influence of optimized GRDDS on the bioavailability of Losartan and the formation extent of active metabolite E3174 by CYP2C9 polymorphism was investigated. Swellable and floatable GRDDS tablets combining hydroxyethyl cellulose (HEC), sodium carboxymethyl cellulose (NaCMC), and sodium bicarbonate were prepared at various compression pressures for evaluating swelling characteristics and floating capacity. Then Losartan was incorporated into optimized formulations for in vitro and in vivo characterizations. An appropriate ratio of HEC to NaCMC, addition of sodium bicarbonate, and compression at lower pressures resulted in the tablets floating over SGF for more than 16 h and swelling to 2 cm in diameter within 3h. The release patterns of Losartan from these tablets were pH-dependent. Results of the clinical trials showed that the mean bioavailability from GRD-A (HEC 91.67%, sodium bicarbonate 3.33% and Losartan 8.33%) was approximately 164%, relative to the immediate-release product (Cozaar). MRT and t(max) values were greater and C(max) values were lower for the GRDDS tablets compared with Cozaa. The lower bioavailability of Losartan in the CYP2C9*1/*1 subjects than CYP2C9*1/*3 subjects was found and could be due to the variety of enzymatic activity.

Rapid-onset sildenafil nasal spray carried by microemulsion systems: in vitro evaluation and in vivo pharmacokinetic studies in rabbits

An oleic acid-based microemulsion system with a member of the Tween series or Cremophor EL as the surfactant and a short-chain alcohol as the cosolvent was developed for rapid-onset intranasal delivery of sildenafil. The phase behaviour and solubilization capacity of the microemulsion system were characterized, and nasal absorption of sildenafil from the microemulsion formulations was investigated in rabbits. Sildenafil displayed a high solubility of 124 mg/mL in the microemulsion consisting of 40% oleic acid, 10% H2O, and 50% Tween 80:ethanol (EA) (at a 1:4 weight ratio). Nasal absorption of sildenafil from this microemulsion was found to be fairly rapid. With a 10-mg dose, the onset of action was arrived instantly following intranasal administration and the duration was over 3 h using an in vivo rabbit studies. In addition, nasal ciliotoxicity studies were carried out using in vivo rat nasal mucosa model and showed no ciliotoxicity. Therefore, the prepared systems are no serious nasal ciliotoxicity for intranasal administration. The microemulsion system composed of oleic acid, Tween 80, EA, and water may be a practical approach for the rapid-onset delivery of sildenafil for the treatment of erectile dysfunction.

Improving the Stability of Astaxanthin by Microencapsulation in Calcium Alginate Beads.

There has been considerable interest in the biological functions of astaxanthin and its potential applications in the nutraceutical, cosmetics, food, and feed industries in recent years. However, the unstable structure of astaxanthin considerably limits its application. Therefore, this study reports the encapsulation of astaxanthin in calcium alginate beads using the extrusion method to improve its stability. This study also evaluates the stability of the encapsulated astaxanthin under different storage conditions. The evaluation of astaxanthin stability under various environmental factors reveals that temperature is the most influential environmental factor in astaxanthin degradation. Stability analysis shows that, regardless of the formulation used, the content of astaxanthin encapsulated in alginate beads remains above 90% of the original amount after 21 days of storage at 25°C. These results suggest that the proposed technique is a promising way to enhance the stability of other sensitive compounds.

Wound-healing effect of micronized sacchachitin (mSC) nanogel on corneal epithelium

The extraction residue of the Ganoderma fruiting body, named sacchachitin, has been demonstrated to have the potential to enhance cutaneous wound healing by inducing cell proliferation. In this study, a nanogel formed from micronized sacchachitin (mSC) was investigated for the potential treatment of superficial chemical corneal burns. Reportedly, mSC has been produced successfully and its chemical properties confirmed, and physical and rheological properties characterized. An in vitro cell proliferation study has revealed that at the concentrations of 200, 300, and 400 μg/mL, mSC nanogel significantly increased Statens Seruminstitut rabbit corneal (SIRC) cell proliferation after 24 hours of incubation. In cell migration assay, migration of SIRC cell to wound closure was observed after 24 hours of incubation with the addition of 200 μg/mL mSC of nanogel. In an animal study, acceleration of corneal wound healing was probably due to the inhibition of proteolysis. In conclusion, the findings of this study substantiate the potential application of sacchachitin in the form of mSC nanogel for the treatment of superficial corneal injuries.