Dexamethasone transport and ocular delivery from poly(hydroxyethyl methacrylate) gels

We explore ocular delivery of dexamethasone (DX) via poly(hydroxyethyl methacrylate) (PHEMA) contact lenses, which are known to have a much higher bioavailability in comparison to eye drops. Three derivatives of dexamethasone (dexamethasone 21-disodium phosphate (DXP), dexamethasone, and dexamethasone 21-acetate (DXA)) are explored. These drugs are loaded in the gels by soaking in aqueous or ethanol solutions, and also by direct addition of the drug to the polymerizing mixture. Dynamic drug concentrations in the aqueous phase are monitored both in loading and release experiments. The data is utilized to determine the partition coefficients and the mean diffusivity, which includes contributions from both bulk and surface diffusion. Finally we utilize the transport model to predict the bioavailability of the three forms of dexamethasone for drug delivery via contact lenses. The transport of each of the drug is diffusion limited with diffusivities of 1.08 x 10(-11) and 1.16 x 10(-11) m(2)/s for DX and DXA, respectively. The diffusivities of DXP depend on concentration and on ionic strength, and are much smaller than those for DX and DXP. The bioavailability for delivery of these drugs via contact lenses is much higher than that for drops, and the bioavailability is the highest for DXA.     

Ofloxacin-induced hallucinations

Drug-induced hallucinations are not uncommon, and may be misdiagnosed as psychiatric illness leading to unnecessary treatment with antipsychotics. If a temporal association of use of a drug having the potential to cause hallucinations is present, mere withdrawal of the drug causes complete improvement in the symptoms. There are reports of various untoward central nervous system adverse events following administration of fluoroquinolones, including delirium, hallucinations and psychosis, even after a single dose. We describe a 5-year-old girl who suffered visual hallucinations following ofloxacin use.KEY WORDS: Adverse events, hallucinations, ofloxacin     

The Effect of Oleic Acid on the Human Ileal Brake and Its Implications for Small Intestinal Transit of Tablet Formulations

Purpose. A human volunteer study was carried out to investigate whether activation of the ileal brake mechanism affects the transit of tablets through the small intestine. Methods. Oleic acid, which has previously been shown to activate the brake, was delivered to the small intestine in a modified release capsule at doses of 300 mg, 600 mg and 1200 mg. The effect of the oleic acid was determined by measuring the transit of two sets of radiolabelled tablets by gamma scintigraphy. One set of tablets was dosed with the capsule and the other one hour later. Results. The results show that in the majority of the volunteers small intestinal residence time was greater with the oleic acid than control. The effect was most pronounced in the tablets given concomitantly with the capsule and with the higher doses of oleic acid. Conclusions. The ileal brake, activated by oleic acid, can slow the transit of tablets through the small intestine.     

Growth inhibition and apoptosis of myeloma cells by the CDK inhibitor flavopiridol.

Although myeloma shows responsiveness in intensive chemotherapy, overall survival remains less than 40% at 2 years. Since myeloma appears to be dependent on cytokines, such as IL-6, we hypothesized that targeting signal transduction molecules could effectively treat myeloma. Two myeloma cell lines U266 and RPMI-8226 and CD38+ myeloma cells were studied by immune complex kinase assay or anti-phosphotyrosine blot for evidence of constitutive activation of tyrosine kinases. Growth arrest and apoptosis were evaluated in these two cell lines following their treatment with specific kinase inhibitors. We found that a variety of Src and Janus kinases were present and constitutively active in U266 and RPMI-8226 cells. Inhibitors of both Src and Janus kinases were inferior to the cyclin-dependent kinase inhibitor, flavopiridol, in inducing both growth arrest with GI50 of 100 nM and apoptosis in both cell lines and CD38+ myeloma cells. Although, flavopiridol did not affect cyclin D1 and cyclin A levels, it inhibited Mcl-1 and Bcl-2 protein levels and cyclin-dependent kinase 2 activity. Flavopiridol is a well-tolerated drug, currently in phase I-II trials for a variety of tumors. A clinical trial using flavopiridol should be performed in patients with myeloma. Its mechanism of action may involve targets other than the cyclin-dependent kinases.     

Phyllanthus amarus: ethnomedicinal uses, phytochemistry and pharmacology: a review

Ethnopharmacological relevance

Phyllanthus amarus Schum. &; Thonn. belongs to the family Euphorbiaceae is a small herb well known for its medicinal properties and widely used worldwide. P. amarus is an important plant of Indian Ayurvedic system of medicine which is used in the problems of stomach, genitourinary system, liver, kidney and spleen. It is bitter, astringent, stomachic, diuretic, febrifuge and antiseptic. The whole plant is used in gonorrhea, menorrhagia and other genital affections. It is useful in gastropathy, diarrhoea, dysentery, intermittent fevers, ophthalmopathy, scabies, ulcers and wounds.

Materials and methods

The present review covers a literature across from 1980 to 2011. Some information collected from traditional Ayurvedic texts and published literature on ethanomedicinal uses of Phyllanthus amarus in different countries worldwide.

Results

Phytochemical studies have shown the presence of many valuable compounds such as lignans, flavonoids, hydrolysable tannins (ellagitannins), polyphenols, triterpenes, sterols and alkaloids. The extracts and the compounds isolated from P. amarus show a wide spectrum of pharmacological activities including antiviral, antibacterial, antiplasmodial, anti-inflammatory, antimalarial, antimicrobial, anticancer, antidiabetic, hypolipidemic, antioxidant, hepatoprotective nephroprotective and diurectic properties.

Conclusion

The present review summarizes information concerning the morphology, ecology, ethnopharmacology, phytochemistry, biological activities, clinical applications and toxicological reports of P. amarus. This review aims at gathering the research work undertaken till date on this plant in order to provide sufficient baseline information for future works and commercial exploitation.     

Evaluation of potential of Zn-pectinate gel (ZPG) microparticles containing mesalazine for colonic drug delivery

BACKGROUND AND THE PURPOSE OF THE STUDY: Pectin derivatives have been utilized for colonic drug delivery (CDD). In this study the effects of different formulation variables upon the characteristics of pectinate microparticles (MPs) prepared by ionotropic gelation technique for colonic delivery of mesalazine was investigated. METHODS: In-vitro drug release of MPs was studied using USP XXIV dissolution apparatus type I, in different fluids e.g. simulated gastric fluid (SGF: pH 1.2), simulated intestinal fluid (SIF: pH 7.4), and simulated colonic fluid (SCF: pH 6.8) of volume 900 ml, at 100 rpm maintained at 37±0.2°C. This study was also performed in the presence of 4% w/v rat caecal content (RCC) using phosphate buffer saline (pH 6.8) as SCF. Gamma scintigraphy study was performed on New Zealand rabbit animal model using (99m) Tc. RESULTS: The results showed that maximum entrapment of mesalazine (86.1±1.7%) and strength of gel network zinc pectinate gel microparticles (ZPGD2) was achieved in cross-linking solution of pH 1.6. Batch of ZPGD2 showed least swelling ratio and drug release. In RCC medium the t(50%) value of CPG-MPs was 3-4 folds greater than ZPG-MPs. Scintigram showed the residence of ZPG-MPs (filled in enteric coated capsule) in colon more than 9 hrs and delivery of almost all the drug loading dose in colon. MAJOR CONCLUSION: The results of this study suggest the designed formulation of ZPG-MPs has the potential to serve as a colonic drug delivery system.     

A Stability-Indicating High Performance Liquid Chromatographic Method for the Determination of Diacerein in Capsules

A stability-indicating HPLC method was developed and validated for the quantitative determination of diacerein in capsule dosage forms. An isocratic separation was achieved using a perfectsil target ODS-3, 250×4.6 mm i.d., 5 µm particle size columns with a flow rate of 1 ml/min and using a UV detector to monitor the eluate at 254 nm. The mobile phase consisted of phosphate buffer:acetonitrile (40:60, v/v) with pH 4.0 adjusted with phosphoric acid. The drug was subjected to oxidation, hydrolysis, photolysis and thermal degradation. Diacerein was found to degrade in acidic, basic, and oxidative stress and also under neutral condition. Complete separation of degraded products was achieved from the parent compound. All degradation products in an overall analytical run time of approximately 10 min with the parent compound diacerein eluting at approximately 4.9 min. The method was linear over the concentration range of 1-10 µg/ml (r² = 0.9996) with a limit of detection and quantitation of 0.01 and 0.05 µg/ml respectively. The method has the requisite accuracy, selectivity, sensitivity, precision and robustness to assay diacerein in capsules. Degradation products resulting from the stress studies did not interfere with the detection of diacerein and the assay is thus stability-indicating.     

Knowledge of results and learning to tell the time in an adult male with an intellectual disability: a single-subject research design

The present study investigated whether knowledge of results, in the form of visual and audible feedback, would increase the accuracy of time-telling in an individual with an intellectual disability. A 19-year-old male with mild intellectual disability participated in this A1-B1-A2-B2 single-subject study design. The task involved correctly identifying the time given on a computer. Data, based on the Wilcoxon signed-rank test, showed that the participant demonstrated a greater number of correct responses during the intervention phases. Incorporating knowledge of results into a learning strategy for this individual with intellectual disability resulted in an increased ability to accurately identify the correct time on an analogue clock. There is a need to replicate the study design to increase the external validity and generalization of results. The strategies described in the present study may also be useful for occupational therapists who teach individuals with intellectual disability to gain skills in their everyday activities of daily living (ADLs).     

Contribution of retinal ganglion cells to the mouse electroretinogram

Purpose

To quantify the direct contribution of retinal ganglion cells (RGCs) on individual components of the mouse electroretinogram (ERG).

Methods

Dark- and light-adapted ERGs from mice 8 to 12 weeks after optic nerve transection (ONTx, n = 14) were analyzed through stimulus response curves for a- and b-waves, oscillatory potentials (OPs), positive and negative scotopic threshold response (p/n STR), and the photopic negative response (PhNR) and compared with unoperated and sham-operated controls, as well as to eyes treated with 6-cyano-7-nitroquinoxaline-2,3-dion (CNQX).

Results

We confirmed in mice that CNQX intravitreal injection reduced the scotopic a-wave amplitude at high flash strength, confirming a post-receptoral contribution to the a-wave. We found that ONTx, which is more specific to RGCs, did not affect the a-wave amplitude and implicit time in either photopic or scotopic conditions while the b-wave was reduced. Both the pSTR and nSTR components were reduced in amplitude, with the balance between the two components resulting in a shortening of the nSTR peak implicit time. On the other hand, amplitude of the PhNR was increased while the OPs were minimally affected.

Conclusion

With an intact a-wave demonstrated following ONTx, we find that the most robust indicators of RGC function in the mouse full-field ERG were the STR components.