DEVELOPMENT AND CHARACTERIZATION OF TOPICAL OPHTHALMIC FORMULATIONS CONTAINING LUTEIN-LOADED MUCOADHESIVE NANOPARTICLES

Objective: To develop and characterize a topical ophthalmic formulation containing chitosan-dextran sulfate nano particles (CDNs) for enhanced ocular bioavailability and stability of lutein.Methods: Lutein-loaded CDNs (LCDNs) were prepared by polyelectrolyte complexation employing oppositely charged polymers, chitosan and dextran sulfate. Effects of the polymer mass ratios, the total amount of polymers, and the amount of EDC and PEG400 on their physicochemical properties as well as the drug release profiles were investigated. The physicochemical stability of LCDNs dispersed in various ophthalmic vehicles and the accompanying microbial contamination were also evaluated.Results: LCDNs possessed a mean size of ~400 nm with a positive surface charge of+30 mV and entrapment efficiency up to 75%. Dissolution profiles followed a Higuchi's square root model, indicating a diffusional release mechanism. LCDNs dispersed in Feldman ophthalmic buffer showed good physical stability with no microbial contamination. The chemical stability of lutein was significantly improved in LCDNs and further improved by the addition of antioxidant in the ophthalmic vehicle.Conclusion: The ophthalmic formulation containing LCDNs, developed in this work, has characteristics suitable for application in ocular surface drug delivery systems.Keywords: Chitosan, dextran sulfate, Nanoparticles, Ophthalmic vehicle, Lutein

DEVELOPMENT AND CHARACTERIZATION OF INDOMETHACIN-LOADED MUCOADHESIVE NANOSTRUCTURED LIPID CARRIERS FOR TOPICAL OCULAR DELIVERY

Objective: To develop and characterize indomethacin loaded-nanostructured lipid carriers (IND-NLCs) for topical ophthalmic delivery with different particle sizes and polymer coating to improve the mucoadhesive property on the ocular surface.Methods: Nanostructured lipid carriers (NLCs) with different solid lipids and surfactants were prepared by the high-pressure homogenization technique. The optimized IND-NLCs was coated with polyethylene glycol 400 (PEG). The physicochemical properties and entrapment efficacy (EE) were examined. In vitro release studies were investigated using the shake-flask method. Ex vivo mucoadhesive studies were assessed by the wash-off test. In addition, the cytotoxicity was assessed by the short time exposure test.Results: IND-NLCs of ~300 and ~40 nm in diameter were successfully produced with a zeta potential of -30 mV and EE of 60–70 %. IND-NLCs prepared with Tween 80 as surfactant could be sterilized by autoclaving. The PEG coating of IND-NLCs did not affect either the particle size or EE. In vitro release showed a prolonged release for 360 min with a burst release of 50-60% occurring within 5 min. The smaller-sized IND-NLCs showed slightly faster release rates and better mucoadhesion to cornea compared to the larger IND-NLCs. PEG-coated IND-NLCs showed the highest mucoadhesion. In addition, IND-NLCs showed less cytotoxicity compared to IND alone. Conclusion: The small and PEG-coated NLCs represents a potentially useful carrier for safe delivery of indomethacin to the ocular surface with increased residence time

PENETRATION OF HYDROPHILIC SULFORHODAMINE B ACROSS THE PORCINE CORNEA EX-VIVO

Objective: Sulforhodamine B (SRB) is a hydrophilic tracer whose fluorescence is unaffected by pH unlike that of carboxyfluorescein. Therefore, SRB may serve as a better tracer when there are significant changes in pH. Thus, in this study, the suitability of SRB to assess the barrier properties of the cellular layers of the cornea was examined using a custom-built confocal scanning micro-fluorometer (CSMF). Methods: The dye solution (0.1% SRB) was prepared in PBS-Ca2+and three experiments were performed ex vivo using freshly isolated porcine eyes. First, we investigated the penetration of SRB across the endothelium by injection of the dye into the anterior chamber. Next, we measured the penetration of SRB across the epithelium after exposing the ocular surface to the dye. Finally, we examined the penetration after exposure to the dye with detergent (Tween 20) and exposure to the dye concomitant with microneedle injuries. The dye concentration profiles across the cornea were measured using CSMF.Results: SRB penetrated the corneal endothelium readily into the stroma following injection into the anterior chamber in a time-dependent manner. Despite accumulation in the stroma, SRB did not partition into the epithelium. In agreement with these findings, the dye did not cross the epithelium after topical administration. Co-administration with Tween 20 and injury to the epithelium with microneedles, however, led to penetration of the dye into the stroma.Conclusions: SRB is a hydrophilic dye that can be used as an alternative fluorescent tracer to assess the barrier function of the cellular layers of the cornea

INTERACTION OF NANOSTRUCTURED LIPID CARRIERS WITH HUMAN MEIBUM

Objective: This study aimed to determine the possibility of nanostructured lipid carriers (NLCs) as a bionic tear film by determining the surface activities of the developed NLCs and their interaction with human meibomian lipid films. Methods: NLCs with different types of solid lipids and surfactants were prepared by a high-pressure homogenizer. The particle size was determined by dynamic light scattering. The surface activities of the NLCs and NLCs mixed with meibomian lipids were measured using a Langmuir trough and the resulting surface pressure area (Π-A) profiles were compared. These lipid films were further analyzed using fluorescence microscopy and scanning electron microscopy (SEM). Results: The particle size of prepared NLCs varied from 38–280 nm based on types of solid lipid and surfactant. All NLCs were highly surface active as indicated by their maximum surface pressure (Πmax). The Π-A profiles of meibum seeded with NLCs showed higher surface pressure than meibum alone and the shape of profiles were dominated by the meibomian lipids. These findings were in agreement with fluorescence and SEM micrographs, which revealed that the NLCs could adsorb and integrate to the meibomian lipid films as well as diffuse from the subphase to the lipid films. Conclusion: NLCs are surface active and can integrate with meibomian lipid films formed stable films. The type of interaction can be tailored by altering the solid lipids used in the formulation of the NLCs which could provide the means to develop efficient formulations for targeting dry eye disease related to a non-functional tear film lipid layer

Streptococcus agalactiae in adults at chiang mai university hospital: a retrospective study

<p>Abstract</p> <p>Background</p> <p>Infection caused by <it>Streptococcus agalactiae</it>, a Group B streptococcus, is an emerging disease in non-pregnant adults. This study describes the epidemiological, clinical, and microbiological characteristics of <it>S. agalactiae </it>infection in adult patients in northern Thailand.</p> <p>Methods</p> <p>A retrospective study was conducted between January 1, 2006 and December 31, 2009 at Chiang Mai University Hospital among patients aged ≥15 years, whose clinical specimens obtained from normally sterile sites grew <it>S. agalactiae</it>.</p> <p>Results</p> <p>One-hundred and eighty-six patients and 197 specimens were identified during the 4-year period. Among 186 patients, 82 were documented as having invasive infection; 42 patients were male (51.2%) with the mean age of 48.5 ± 19.4 years (range 17, 83). Fifty-three patients (64.6%) had underlying medical conditions; 17 patients (20.7%), 10 (12.2%), 8 (9.7%) had diabetes, chronic renal diseases, and malignancy, respectively. Among 40 patients (48.8%) with bloodstream infection, no other site of infection was determined in 29 (35.4%) patients. In the remaining 11 patients, 5 patients (6.1%), 5 (6.1%), and 1 (1.2%) had meningitis, arthritis, and meningitis with arthritis, respectively. Forty-two patients (51.2%) presented with localized infection, i.e., subcutaneous abscess (19 patients, 23.2%), chorioamnionitis (10 patients, 12.2%), urinary tract infection (5 patients, 6.1%), arthritis (3 patients, 3.7%), meningitis (2 patients, 2.4%), and spontaneous bacterial peritonitis, uveitis, and tracheobronchitis (1 patient each, 1.2%). The overall mortality was 14.6% (12 patients).</p> <p>Conclusions</p> <p><it>S. agalactiae </it>infection is a growing problem in non-pregnant patients, particularly in those with underlying medical conditions. Physicians should add <it>S. agalactiae </it>infection in the list of differential diagnoses in patients with meningitis and/or septicemia.</p

A study using Andrographis paniculata in diet on growth performance of Betong chicken: Starting period

An eight-week experiment was conducted to study using Andrographis paniculata (AP) on the growth performance of Betong chickens (0-8 weeks of age). Three hundred and fifteen head of 1 day old (mixed sex) betong chicks were randomly allotted to 7 dietary treatments, in a completely randomized design experiment. There were three replications in each treatment with 15 chicks per pen. The dietary treatments were 1) basal diet (control), 2) basal diet + 0.1% AP, 3) basal diet + 0.2% AP, 4) basal diet + 0.3% AP, 5) basal diet + 0.5% AP, 6) basal diet + 0.6% AP and 7) basal diet + antibiotic 0.2%, respectively. The results showed no significant (P>0.05) difference among treatments in terms of weight gain, feed intake, feed conversion, mortality rate and feed cost when AP was included up to 0.1-0.3 % of the diet compared with basal diet and basal diet + antibiotic. However, at levels higher than 0.5% AP, it tended to lower growth performance and feed intake thus causing inferior feed conversion ratio. Feed cost was also dramatically increased with the increasing levels of AP in the diet. No significant difference in mortality rate was found among groups. The average mortality was 1.37%

Preparation of polydivinylbenzene/natural rubber capsule encapsulating octadecane: Influence of natural rubber molecular weight and content

The encapsulation of octadecane (OD) as heat storage material was studied. The core-shell polydivinylbenzene (PDVB)/natural rubber (NR) capsules encapsulating OD was prepared using the Self-assembling of Phase Separated Polymer (SaPSeP) method by suspension polymerization. The mixture of dispersed phase consisting of DVB, NR, OD and benzoyl peroxide was added in polyvinyl alcohol aqueous solution and then homogenized at 5,000 rpm for 5 minutes. The obtained monomer droplet emulsion was subsequently polymerized at 80°C for 8 hours resulting in PDVB/NR capsule encapsulating OD. The influence of molecular weight and content of NR on the encapsulation efficiency and thermal properties of the encapsulated OD were investigated. It was found that both factors affected on the preparation of PDVB/NR/OD capsule. High molecular weight NR restricted phase separation of formed PDVB. High NR content also reduced phase separation of PDVB due to the increase of internal viscosity. Then, only the incorporation of appropriate molecular weight and content of NR resulted in the formation of PDVB/NR/OD capsule

Immunohistochemical study of acute and chronic toxoplasmosis in experimentally infected mice.

Acute and chronic Toxoplasma infections were evaluated in mice using stage specific antibodies and immunocytochemistry. Mice with acute toxoplasmosis were less active, had erectile body hair and seldom took food or water resulting in weight loss. All mice died within 7 days post-inoculation. The immunohistochemical technique enhanced visualization of parasites allowing their distribution to be accurately followed. Following intraperitoneal infection, tachyzoites were initially identified on the surface of the liver and spleen. There was a rapid increase in the number of tachyzoites associated with invasion from the surrounding connective tissue into the organs with formation of inflammatory lesions in the liver. The focal inflammatory lesions showed increasing numbers of tachyzoites with the period post-inoculation. Similar increases in tachyzoites were observed for the spleen. In contrast, only a few individual tachyzoites were seen in the brain at the final time point. In chronic infections, the mice were asymptomatic but tissue cysts containing large numbers of bradyzoites were observed in all brains with the average number of 295 tissue cysts per half brain and the average cystic size of 46.02 +/- 5.08 microm. By histology and immunostaining, the tissue cysts were readily identifiable along with a mild inflammatory cell infiltration into the meninges and perivascular cuffing. Double immunocytochemical labelling confirmed the exclusive presence of tachyzoites during the acute phase and bradyzoites during the chronic phase