Metabolism and Pharmacokinetics of the Anti-Tuberculosis Drug Ethionamide in a Flavin-Containing Monooxygenase Null Mouse.

Metabolism and Pharmacokinetics of the Anti-Tuberculosis Drug Ethionamide in a Flavin-Containing Monooxygenase Null Mouse.

Pharmaceuticals (Basel). 2012 Nov 1; 5(11): 1147-1159
Palmer AL, Leykam VL, Larkin A, Krueger SK, Phillips IR, Shephard EA, Williams DE

Multiple drug resistance (MDR) in Mycobacterium tuberculosis (mTB), the causative agent for tuberculosis (TB), has led to increased use of second-line drugs, including ethionamide (ETA). ETA is a prodrug bioactivated by mycobacterial and mammalian flavin-containing monooxygenases (FMOs). FMO2 is the major isoform in the lungs of most mammals, including primates. In humans a polymorphism exists in the expression of FMO2. FMO2.2 (truncated, inactive) protein is produced by the common allele, while the ancestral allele, encoding active FMO2.1, has been documented only in individuals of African and Hispanic origin, at an incidence of up to 50% and 7%, respectively. We hypothesized that FMO2 variability in TB-infected individuals would yield differences in concentrations and ratios of ETA prodrug and metabolites. In this study we assessed the impact of the FMO2 genetic polymorphism on the pharmacokinetics of ETA after administration of a single oral dose of ETA (125 mg/kg) to wild type and triple Fmo1/2/4-null mice, measuring levels of prodrug vs. metabolites in plasma collected from 0 to 3.5 h post-gavage. All mice metabolized ETA to ETA S-oxide (ETASO) and 2-ethyl-4-amidopyridine (ETAA). Wild type mice had higher plasma concentrations of metabolites than of parent compound (p = 0.001). In contrast, Fmo1/2/4-null mice had higher plasma concentrations of parent compound than of metabolites (p = 0.0001). Thus, the human FMO2 genotype could impact the therapeutic efficacy and/or toxicity of ETA. HubMed – drug


Delayed onset chloroquine retinopathy presenting 10 years after long-term usage of chloroquine.

Middle East Afr J Ophthalmol. 2013 Jan; 20(1): 89-91
Kazi MS, Saurabh K, Rishi P, Rishi E

Chloroquine retinopathy is a known complication of long-term use of chloroquine. This retinopathy can appear even after usage of chloroquine has stopped. The present case report describes the history and clinical features of chloroquine retinopathy developing a decade after discontinuing the drug. HubMed – drug


In vivo confocal microscopy in chloroquine-induced keratopathy.

Middle East Afr J Ophthalmol. 2013 Jan; 20(1): 77-9
Paladini I, Menchini U, Mencucci R

In vivo confocal microscopy is becoming a mandatory examination to study corneal abnormalities such as drug deposits in systemic disease. A female diagnosed with fibromyalgia on systemic chloroquine for 9 months presented for an ophthalmic examination. Confocal microscopy was performed using the Confoscan 4 (Nidek Co. Ltd., Gamagori, Japan) and multiple highly reflective deposits in the epithelial basal cells were found, that were consistent with choloquine. Deposits were also present in the wing cell layer. In the anterior stroma these deposits were rare. Atypically shaped and branched nerves were also present in the anterior stroma. Corneal deposits of chloroquine can be evaluated by confocal microscopy. Confocal microscopy provides information on corneal metabolism and physiology. Chloroquine keratopathy can affect the anterior stroma in addition to the epithelium. HubMed – drug


Nanotechnology approaches for ocular drug delivery.

Middle East Afr J Ophthalmol. 2013 Jan; 20(1): 26-37
Xu Q, Kambhampati SP, Kannan RM

Blindness is a major health concern worldwide that has a powerful impact on afflicted individuals and their families, and is associated with enormous socio-economical consequences. The Middle East is heavily impacted by blindness, and the problem there is augmented by an increasing incidence of diabetes in the population. An appropriate drug/gene delivery system that can sustain and deliver therapeutics to the target tissues and cells is a key need for ocular therapies. The application of nanotechnology in medicine is undergoing rapid progress, and the recent developments in nanomedicine-based therapeutic approaches may bring significant benefits to address the leading causes of blindness associated with cataract, glaucoma, diabetic retinopathy and retinal degeneration. In this brief review, we highlight some promising nanomedicine-based therapeutic approaches for drug and gene delivery to the anterior and posterior segments. HubMed – drug