Sarunyoo Songkro

Development of a pH-responsive drug delivery system for enantioselective-controlled delivery of racemic drugs.

This study aimed to develop enantioselective-controlled drug delivery systems for selective release of the required (S)-enantiomer in a dose formulation containing a racemic drug in response to pH stimuli. The recognition system was obtained from a nanoparticle-on-microsphere (NOM) molecularly imprinted polymer (MIP) with a multifunctional chiral cinchona anchor synthesised by suspension polymerisation using ethylene glycol dimethacrylate as a cross-linker. (S)-omeprazole was used as an imprinting molecule conferring stereoselectivity upon the polymers. The ability of the prepared recognition polymers to selectively rebind (S)-omeprazole was evident at different pH levels (the highest being at pH 7.4). The partial selective-release phenomenon of the (S)-enantiomer in MIP-containing composite cellulose membranes with increased vehicular racemic omeprazole concentrations was highly pH-dependent. Cinchona-bonded polymers imprinted with (S)-omeprazole could recognise the moldable contact site of (S)-omeprazole independently of its chirality; this is responsible for the delivery of (S)-enantiomer from racemic omeprazole. The controlled-release drug devices were fabricated with synthesised composite latex, and consisted of a pH stimuli-responsive poly(hydroxyethyl methacrylate) (HEMA) and polycaprolactone-triol (PCL-T) blend, and a MIP with preloaded drug, along with pH 7.4 buffer in the devices interior. The results demonstrate that drug delivery systems containing (S)-omeprazole imprinted cinchona-polymer nanoparticle-on-microspheres may maximise efficacy while minimising dose frequency.

Investigation of inclusion complexes of citronella oil, citronellal and citronellol with β-cyclodextrin for mosquito repellent

The aim of this study was to prepare the inclusion complexes of citronella oil, citronellal or citronellol with β-cyclodextrin and evaluate their physicochemical properties using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). A kneading method was employed to prepare the inclusion complexes and weight ratios of each of the active substance to β-cyclodextrin were 1:1 (1:1 CPX) and 1:2 (1:2 CPX). For comparison purposes, physical mixtures of these active compounds and β-cyclodextrin were also prepared and investigated. Unlike the physical mixtures, the SEM technique revealed drastic changes in the shapes and morphologies of the particles for the inclusion complexes. Furthermore, the FTIR and DSC results seemed to reveal some interactions between the active substance and β-cyclodextrin. The o/w lotions, which contained 10% w/w citronella oil (normal citronella oil; 1:1 CPX or 1:2 CPX), were formulated using Cremophors as emulsifiers. With modified Franz diffusion cell and synthetic membrane, the release rates of citronella oil from the lotions containing the inclusion complexes were significantly lower than that from the prepared lotion containing normal citronella oil. The mosquito (Aedes aegypti) repellent efficacy of the lotions containing citronella oil, citronellal or citronellol (both normal and inclusion complexes) was further evaluated by human-bait technique. The highest mosquito repellent activity was observed in the formulation which contained citronella oil–β-cyclodextrin inclusion complex at weight ratio of 1:1.

Topical Anti‐inflammatory Potential of Standardized Pomegranate Rind Extract and Ellagic Acid in Contact Dermatitis

The present study evaluated the topical anti‐inflammatory potential of a standardized pomegranate rind extracts (SPRE) in parallel with its marker compound ellagic acid (EA, 13% w/w) against a mouse model of contact dermatitis. In the phenol‐induced mouse ear edema, topical application of SPRE (5, 2.5, and 1 mg/ear) and EA (0.65, 0.325, and 0.13 mg/ear, equivalent to its content in SPRE) dose‐dependently reduced the ear edema with the maximal inhibition of 79.12% and 73.63%, respectively. Triamcinolone (0.1 mg/ear) and diclofenac (1 mg/ear) as reference drugs inhibited the edema by 73.63% and 37.91%. Myeloperoxidase (MPO) activity in the mouse ear was also decreased by SPRE and EA up to 69.68% and 68.79%, respectively. Triamcinolone and diclofenac decreased the MPO activity by 76.66% and 80.14% similarly. The results indicated that topical application of SPRE and EA is promising for use in the treatment of inflammatory skin disorders. Copyright

Effects of glucam P-20, vanillin, and fixolide on mosquito repellency of citronella oil lotions.

ABSTRACT The objective of this study was to investigate the effects of three fragrance fixatives, Glucam P-20, Vanillin, and Fixolide, on the mosquito repellent property of citronella oil lotions. In the current study, two formulae (A and B) of oil-in-water citronella oil lotions were formulated using different ingredients (emulsifiers [Cremophors or Emulwax], stiffening agents, and emollients). Citronella oil was used at 10% wt:wt. The weight ratios tested between citronella oil and each fixative were 1:0.25, 1:0.5, and 1:1. Overall, 20 formulations, including one with no fixatives for both A and B, were produced, A1–A10 and B1–B10. The repellent activities of these 20 lotions against Aedes aegypti (L.) were tested using a human-bait technique. The types and concentrations of fixatives as well as the compositions of the formulations did affect the protection time of the citronella oil lotions. The lotion containing Emulwax and 5% vanillin (B6) was the most effective repellent. It provided the longest protection time of 4.8 h, which exceeded the minimum requirement of 2 h set by the National Institute of Health, Thailand. The shortest protection time (1 h) was observed in the lotion containing Emulwax and 2.5% Glucam P-20 (B2). It could be concluded that the tested fixatives affected the repellent activity of the citronella oil lotions.

In vitro release, skin permeation and retention of benzophenone-3 from microemulsions (o/w and w/o)

The major aim of this work was to investigate the effect of microemulsion type on the in vitro release, skin permeation and skin retention of benzophenone-3 microemulsions. Based on the microemulsion regions of ternary phase diagrams, two types of microemulsions were formulated. This included w/o microemulsions containing Tween 20 or Tween 80 (surfactant), Eutanol G (oil) and water and o/w microemulsions containing additional component, a 1:1 mixture of surfactant and cosurfactant (isopropyl alcohol). Overall, four microemulsion formulations at ratio of 18:72:10 (oil:surfactant or mixtures of surfactant and cosurfactant:water) were prepared. Each blank microemulsion was incorporated with 5 % w/w benzophenone-3, a sunscreen. Physicochemical property and stability (both physical and chemical) of the prepared formulations were acceptable. All microemulsions showed negative zeta potential values. The mean droplet sizes of the w/o type (14–54 nm) were much smaller than the o/w type (136–210 nm). The release kinetics of all formulations followed zero order. Unlike the skin retention, microemulsion type affected the release characteristics and skin permeation of benzophenone-3. The o/w microemulsions showed markedly high release rates and skin permeation rates. The w/o microemulsions providing low transdermal fluxes may be promising for topical delivery of the sunscreen.

Investigation of enhancing activity and skin irritation of Zingiber officinale, Zingiber cassumunar and Curcuma zedoaria

The penetration enhancing effect of essential oils extracted from rhizomes of Zingiber officinale, Zingiber cassumunar and Curcumar zedoaria on the skin permeation of diclofenac sodium was evaluated in vitro using modified Franz diffusion cell and Wistar rat skin. The essential oils were tested at 1, 3 and 5% (w/v) in the vehicle hydroalcoholic mixture (ethanol: water (1:1 v/v)). The skin permeation of diclofenac sodium was remarkably enhanced in the presence of these three essential oils. Overall, the rank order of the enhancing activities of these oils was Zingiber officinale > Zingiber cassumunar > Curcuma zedoaria. Furthermore, the essential oil at 5% appeared to give the greatest enhancement. For the in vivo skin irritation study, these oils were tested at 1 and 5% in the vehicle and at 100%. These test solutions including the vehicle were applied to the abdominal surfaces of the Wistar rats and kept in contact with these areas for 24 h. After a biopsy technique, the skin irritation was evaluated under microscopic observation and histological scores were used as an index of skin damage caused by the test compounds. The skin irritation study revealed that the vehicle had no discernible effects in histological appearance in rat skin. The essential oils at concentrations of 1 and 5% in hydroalcoholic mixture and at 100% were found to cause skin irritation in different degrees. The most severe skin damage was observed with the 1% of these oils whereas the 5% of these oils were classified as mild irritants.

Investigation of plaunoi-loaded micro/nanoemulsions for the treatment of dermatitis: formulation, évaluation and skin irritation studies

The main objective of this work was to formulate microemulsions and nanoemulsions as delivery vehicles for plaunoi extract (Croton stellatopilosus Ohba) to treat dermatitis. Plaunotol, a constituent of plaunoi, has been shown to possess antimicrobial activity. In this work, 2 % w/w plaunoi-loaded formulations were prepared and investigated for their physical property (size and viscosity), efficacy and safety. The plaunoiloaded microemulsions (ME1-P (w/o), ME2-P (o/w)) and nanoemulsion (NE-P (o/w)) had different average sizes and apparent viscosities. Using modified Franz diffusion cell and a synthetic membrane, the release rate of plaunotol from NE-P was found to be the highest. With regard to the in vitro skin penetration, only o/w microemulsion (ME2-P) could deliver plaunotol through the newborn pig skin into the receptor fluid. Unlike ME1-P, the accumulation of plaunotol within the excised newborn pig skin was observed in ME2-P and NE-P. The antimicrobial property of the formulations was further investigated using a cylinder- plate method. Staphylococcus aureus, Staphylococcus epidermidis and Propionibacterium acnes were the tested gram microorganisms. It was found that the plaunoi-loaded formulations exhibited somewhat improved antibacterial activity for S. aureus and S. epidermidis when compared with the blank formulations. The skin irritation was not observed in all treated rabbits for the nanoemulsion NE-P. Both ME1-P and ME2-P showed slight erythema. These results suggest a potential use of nanoemulsions for topical delivery of plaunoi extract.

Cholesteryl Cetyl Carbonate as a Smart Material for Drug Delivery Application

Cholesteryl cetyl carbonate (CCC) was synthesized from cetyl alcohol and cholesteryl chloroformate. Cholesteryl cetyl carbonate mixture (CCCM) was obtained from the reaction. CCCM was purified by liquid-liquid extraction and flash column chromatography. Thermotropic liquid crystal was formed in both pure CCC and CCCM. CCCM is composed of cholesterol, cetyl alcohol and CCC (30:20:50, weight ratio). FTIR and NMR were employed to confirm the functional groups of CCC. Thermal properties of CCC were determined by DSC and polarized light microscope. The phase transition from solid crystal to smectic appears at 42 °C, smectic to nematic appears at 54 °C and nematic to isotropic liquid appears at 73 °C. Indomethacin (IDM) could be incorporated into CCC and properties of CCC-IDM mixture stayed as liquid crystalline phase.