Formulation and in vitro evaluation of ofloxacin-ethocel controlled release matrix tablets prepared by wet granulation method: influence of co-excipients on drug release rates

Being controlled release dosage forms, tablets allow an improved absorption and release profiles of Ofloxacin. The fact that drugs with fine particles size can be compressed well after wetting, so in our research studies Ofloxacin controlled release matrix tablets were prepared by wet granulation technique. In order to investigate the potential of Ethyl cellulose ether derivatives as a matrix material, Ofloxacin formulations with different types and grades of Ethocel were prepared at several drug-to-polymer ratios. The method adopted for in vitro drug release studies was USP Method-1 (rotating Basket Method) by Pharma test dissolution apparatus using phosphate buffer 7.4 pH as a dissolution medium. Various Kinetic models were employed to the formulations for the purpose of determination of release mechanism. A comparative study was performed between the tested Ofloxacin-Ethocel formulations and a standard reference obtained from the local market. F1 dissimilarity factor and f2 similarity factor were applied to the formulations for the checking of dissimilarities and similarities between the tested formulations and reference standard.

Electrogram-based optimal atrioventricular and interventricular delays of cardiac resynchronization change individually during exercise

BACKGROUND

Limited data suggest that optimal atrioventricular (AV) and interventricular (VV) delays are different at rest than during exercise in patients with heart failure. We assessed the feasibility and reproducibility of an electrogram-based method of optimization called QuickOpt at rest and during exercise.

METHODS

Patients with a St Jude Medical cardiac resynchronization therapy implantable cardioverter-defibrillator were subjected to a graded treadmill test, and QuickOpt was repeatedly measured prior to, during, and after the exercise.

RESULTS

Twenty-four patients (16 males, aged 67.4 ± 7.7 years) participated. At rest, delays (in ms) were 110.4 ± 20.1 for sensed AV delay and -70 (LV pacing first) to +20 (RV pacing first) for VV delay. The changes in QuickOpt-derived delays at rest were not significant despite change in body position. During exercise, QuickOpt-derived AV delays did not change in 11 patients, were shorter during peak exercise in 8 patients, and were longer in 3 patients (average value during peak exercise was 126.5 ± 15.8 ms, P = 0.04 compared to baseline). The QuickOpt-derived VV delay gradually shifted toward earlier right ventricular pacing during exercise in 19 patients, while no changes were seen in 3 patients, and a shift occurred toward earlier left ventricular pacing in 2 patients (average value during peak exercise was -30.7 ± 22.2; P = 0.001 compared to baseline). There was no correlation between changes in the QuickOpt-derived AV and VV delays and heart rate.

CONCLUSIONS

The application of electrogram-based algorithm is feasible both at rest and during exercise. The results are reproducible. QuickOpt-derived AV and VV delays individually change during exercise.

Prevalence and risk factors for cervical and lumbar spondylosis in interventional electrophysiologists

 

INTRODUCTION

The volume and complexity of interventional electrophysiology procedures have increased greatly over the last 20 years. Anecdotal reports from Canada and elsewhere have suggested an important prevalence of neck and back problems in interventional electrophysiologists.

METHODS AND RESULTS

To quantify the scope of neck and back problems, we surveyed 70 interventional electrophysiologists in Canada using an electronic survey with in person and email reminders. We also surveyed an age- and gender-matched group of noninterventional cardiologists. We received responses from a total of 58 of 70 interventional electrophysiologists (response rate 82.8%). There was a significantly higher prevalence of cervical spondylosis among electrophysiologists compared to matched noninterventional cardiologists (20.7% compared to 5.5%, P = 0.033). There was a trend for increased prevalence of lumbar spondylosis (25.9% compared to 16.7%, P = 0.298). Among electrophysiologists, those with cervical spondylosis were older (49.83 ± 10.48 years compared to 44.57 ± 9.20, P = 0.092) and had worked in the specialty for longer in comparison to unaffected physicians (19.67 ± 10.06 years compared to 13.37 ± 8.97 years, P = 0.039). All other variables including gender, height, weight, BMI, type of lead, weekly average lead time, and % of time standing in electrophysiology laboratory were not different. On multivariable analysis there were no independent predictors of disease.

CONCLUSIONS

There is a significant increased prevalence of cervical spondylosis among interventional electrophysiologists. Programs to improve ergonomics and minimize time spent wearing lead are needed. The same vigilance that is used to ensure radiation safety in the laboratory should be applied to create ergonomic safety. 

Optical properties of the mouse eye

The Shack-Hartmann wavefront sensor (SHWS) spots upon which ocular aberration measurements depend have poor quality in mice due to light reflected from multiple retinal layers. We have designed and implemented a SHWS that can favor light from a specific retinal layer and measured monochromatic aberrations in 20 eyes from 10 anesthetized C57BL/6J mice. Using this instrument, we show that mice are myopic, not hyperopic as is frequently reported. We have also measured longitudinal chromatic aberration (LCA) of the mouse eye and found that it follows predictions of the water-filled schematic mouse eye. Results indicate that the optical quality of the mouse eye assessed by measurement of its aberrations is remarkably good, better for retinal imaging than the human eye. The dilated mouse eye has a much larger numerical aperture (NA) than that of the dilated human eye (0.5 NA vs. 0.2 NA), but it has a similar amount of root mean square (RMS) higher order aberrations compared to the dilated human eye. These measurements predict that adaptive optics based on this method of wavefront sensing will provide improvements in retinal image quality and potentially two times higher lateral resolution than that in the human eye.

A review of problems, obstacles and sequelae encountered during femoral lengthening : uniplanar versus circular external fixator

There is currently a consensus regarding the superiority of circular type external fixators over uniplanar fixators for lengthening of the tibia, but femoral lengthening is still subject to the surgeon's preference. This study compares the occurrence rates of significant problems, obstacles and sequelae between these two techniques. Fifty patients (29 male, 21 female), with a mean age of 20 years were assigned to a circular type fixator group (54 lengthening segments), whereas 60 patients (29 male, 31 female), with a mean age of 20 years were assigned to a uniplanar fixator group (67 lengthening segments). The incidence of knee stiffness was significantly higher in the circular external fixator group (031 per segment) compared to the uniplanar external fixator group (0.13 per segment) (p < 0.05). The incidence of pain during lengthening was higher in the circular external fixator group, and patient satisfaction was higher in the uniplanar external fixator group. We recommend the uniplanar external fixator as a preferable device for femoral lengthening.

Scanning system design for large scan depth anterior segment optical coherence tomography

In telecentric scanning a large lateral scan area leads to an increase in the angle of incidence on each of the four anterior ocular surfaces (two for the cornea and two for the crystalline lens), causing significant reduction in the signal obtained from regions farther from the optical axis. We propose an optical coherence tomography scanning system, which achieves nearly normal incidences across the lateral locations of the four ocular surfaces. This provides an increase in the amount of light scattered back to the system, resulting in a higher signal-to-noise ratio (SNR). The images of a model eye obtained with the proposed scan and conventional telecentric scan were compared. SNR improvement of 5dB and 12dB was observed for the anterior and the posterior lens surfaces, respectively. For the posterior corneal surface SNR improvement of 4dB was observed, while the SNR improvement for the anterior corneal surface was 0.7dB.

Laryngocele masquerading as a soft tissue neck mass

Laryngocele is a rare entity which can clinically present as a neck mass and requires Computed Tomography (CT) and laryngoscopy for diagnosis. We present an interesting case of bilateral laryngocele in a 45-year-old male presented clinically as hoarseness and left sided neck mass without any history of predisposing factors. Ultrasonography (USG) and CT features of laryngocele is also presented here.

Relationship of Age at First Live Birth, Parity and Duration of Breast Feeding with Non Familial Breast Cancer in Pakistani Women. A Study of the Cancer Research Group Pakistan

Background and objectives; This multicenter case control study is being conducted at seven different centers in Pakistan in order to find out the association and relationship of different hormonal and reproductive factors with breast cancer. These factors have been identified either as risk factors or protective factors for breast cancer in other communities but not in Pakistani women. Preliminary results from four centers are being reported here.Method; Patients attending these cancer treatment centers were interviewed by the trained medical personals and the findings were recorded in a proforma. Age and area matched unrelated controls were randomly selected and interviewed with same questions and findings were recorded in a corresponding proforma. SPSS version 11.5 was used for statistical analysis.Results; From June, 2008 to May, 2009 six hundred eighty eight cases were compared with an equal number of controls. Median age of cases was 47 years (26-70 years) and controls 47.5 years (25-71 years). One hundred ninety eight of cases (28.78%) and 208 of controls (30.23 %) gave first full term live birth before the age of 20. Sixty two cases (09.01%) and 38 controls (5.52%) gave first full term live birth after the age of 30. Seventy one cases and 65 controls were nulliparous.Fifty cases (07.27%) and 51 controls (07.41%) had only one child whereas 104 (15.12%) cases and 118 controls (17.15%) had more then 7 children.Breast feeding duration was more then 24 months in 410 (72.31%) of all women who had more then 1 child. Duration of breast feeding in cases Vs. control in women with 2-4 children, 5-7 children and more then 7 children was similar. Statistical analysis reveals that first live birth below the age of 20 and duration of breast feeding of greater then 24 months duration are not associated as protective factors in this patient population. Odds ratio of 1.35, 95% CI; 1.01-1.70 and 1.014, 95% CI; 0.80-1.22 respectively. Age at first live birth after 30 years of age seems to be positively associated with breast cancer. Odds ratio of 1.75, 95% CI; 1.15-2.65. These results do not support the young age at first full term pregnancy and prolonged duration of breast feeding as protective factors against the breast cancer.Key Words: Breast Cancer, Breast feeding, Parity, Risk Factor

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2071.

Drug-induced QT prolongation and proarrhythmia: an inevitable link?

One of the most feared potential adverse effects of many drugs is life threatening or fatal arrhythmia--particularly torsade de pointes (TdP) ventricular tachycardia in conjunction with QT prolongation. To fully understand the implications of QT prolongation, it is essential to have an understanding of the ion currents that comprise repolarization and their relation to electrophysiological abnormalities associated with TdP. Also, the QT interval is subject to patient-specific and sometimes idiosyncratic variability. The following questions are addressed: How close is the relationship between QT prolongation and proarrhythmia? How accurately do QT-interval measurements reflect cardiac repolarization? How representative is a single QT measurement with respect to the QT response to a drug? The presumed relationship between the QT interval and myocardial repolarization will be deconstructed, demonstrating that most of the important aspects of repolarization, and subsequent arrhythmogenesis, cannot be understood only through the simple numerical measurement of the QT interval. Repolarization reserve is also discussed. Suggestions for refining the understanding of drug-induced QT prolongation, TdP, and shortcomings of some current definitions are outlined. We speculate on possible future developments in understanding this relationship.

Correcting anterior corneal aberration and variability of lens movements in keratoconic eyes with back-surface customized soft contact lenses

Customized contact lenses are limited in their correction performance, especially on irregular corneas, owing to decentration and rotation of the lenses. To overcome this limitation, we proposed to customize the back surface of soft contact lenses to match the anterior irregular corneal surface. These lenses were designed to correct anterior corneal aberrations and to improve lens stability. Although in keratoconic eyes the anterior corneal aberrations were effectively corrected, significant residual aberrations were observed. The internal optics, especially the posterior surface of the cornea, was the main source of these residual aberrations. Compared with conventional soft contact lenses, lens stability, on average over three eyes, was improved by a factor of 2 for horizontal and vertical decentrations and a factor of 5 in rotational orientation with the back-surface customized lenses.