Methotrexate bearing calcium pectinate microspheres: a platform to achieve colon-specific drug release

In the present work calcium pectinate (Ca-pectinate) microspheres were prepared to deliver methotrexate in the environment of colon. Calcium pectinate microspheres were prepared by modified emulsification method using calcium chloride as cross linker. All the formulations were evaluated for various physicochemical parameters. Particle size of the microspheres was determined using laser diffraction particle size analyzer. Encapsulation efficiency was determined by digesting with enzyme pectinase for 24 hours and swellability by equilibrium swelling in simulated gastrointestinal fluid. The in vitro drug release studies were performed in simulated gastric fluid for 2 hours and simulated intestinal fluid for 3 hours. In vitro release rate studies were also carried out in simulated colonic fluid in presence of rat caecal contents. Moreover, release rate studies were also carried out after enzyme induction by treating the rats with 1 ml of 1% w/v aqueous dispersion of pectin for 7 days. Mean particle size of the microspheres was found to be in the range of 20.82+/-1.34 to 32.26+/-1.59 microm whereas the entrapment efficiency varied from 52.28+/-0.32 to 74.01+/-3.32%. The in vitro drug release studies in simulated gastric fluid and simulated intestinal fluid showed that only 8.15+/-0.49% drug was released in 5 hours whereas most of the loaded drug was released in simulated colonic fluid containing pectinase. In vitro release rate study showed release of 69.94+/-3.46% of drug in presence of 3% rat caecal contents, which was further increased to 94.43+/-4.48% when enzyme induction was carried out for 7 days. Thus, it is concluded that calcium pectinate microspheres can be used to effectively localize the release of drug in the physiological environment of colon.

Dissolution stability studies of suspensions of prolonged-release diclofenac microcapsules prepared by the Wurster process: I. Eudragit-based formulation and possible drug-excipient interaction

The aim was to evaluate possible interaction in solid and liquid state of the drug with formulation excipients consequent to very fast drug release of diclofenac-Eudragit prolonged release microcapsules. The microcapsules were prepared by drug layering on calcium carbonate cores and coated with Eudragit RS 30D and L30D-55 as previously reported. Suspension of the microcapsules was prepared using microcrystalline cellulose/sodium carboxymethyl cellulose (Avicel CL-611) as medium. In vitro dissolution testing of the suspension was done, and, based on the dissolution results, possible interaction between diclofenac and Eudragit and Avicel in the medium was studied. Powder X-ray diffraction (PXRD) and differential scanning calorimetry (DSC) analyses were performed using 1:1 binary, 1:1:1 ternary mixtures and a ratio equivalent to that in the formulation. The mixtures were prepared by mixing the dispersions--Eudragit RS 30D or L30D-55 with the drug or other components, followed by drying at 60 degrees C for 48 h. Dry mixing was done using the powder equivalents of the polymers, Eudragit RS PO and L100-55, Avicel and calcium carbonate. In vitro dissolution of the suspended microcapsules showed a very fast release after 48 h (T50 = <1 h) compared to the solid microcapsules (T50 = 6 h). DSC curves of the formulation components or microcapsules did not show the characteristic endothermic peak of diclofenac at 287 degrees C. Powder X-ray diffraction of the binary or ternary mixtures of diclofenac and Eudragit polymers indicated reduction, shift or modification of the crystalline peaks of the drug or excipients at 2theta of 12 degrees and 18 degrees , suggestive of interaction. Some changes in drug peak characteristics at 18 degrees and 23 degrees were observed for Avicel/drug mixture, though not significant. The DSC curves of the binary mixture of diclofenac co-dried with liquid forms of Eudragit (i.e. RS 30D or L30D-55) revealed greater interaction compared to the curves of drug and powdered forms of Eudragit (RS PO or L100-55). This was depicted by greater shift in fusion points of the mixtures relative to the drug. However, comparing the RS and L-type Eudragit, the latter generally showed greater interaction with the drug. Interaction between diclofenac and L-type Eudragit polymers can occur in liquid formulations.

Stanford University Network for Diagnosis of Retinopathy of Prematurity (SUNDROP): 12-month experience with telemedicine screening

BACKGROUND/AIMS

To report the 1-year experience of the Stanford University Network for Diagnosis of Retinopathy of Prematurity (SUNDROP) telemedicine initiative.

METHODS

Forty-two consecutively enrolled infants who met ROP examination criteria were screened between 1 December 2005 through 30 November 2006 with the RetCam II and evaluated by the SUNDROP reading centre at Stanford University. Nurses obtained five images in each eye. All patients also received a dilated examination by the author within 1 week of discharge from the hospital. Outcomes included referral-warranted disease, need for treatment and anatomical outcomes. Referral-warranted disease was defined as any Early Treatment Retinopathy of Prematurity (ROP) Disease Type 2 or greater, or any plus disease. A retrospective analysis of 84 eyes, 131 unique examinations and 1315 unique images from the SUNDROP archival data is reported here.

RESULTS

In the initial 12-month period, the SUNDROP telemedicine screening initiative had not missed any referral warranted ROP. Calculated sensitivity and specificity was 100% and 95%, respectively. No patient progressed to retinal detachment or other adverse outcomes.

CONCLUSIONS

The SUNDROP telemedicine screening initiative for ROP has proven to have a high degree of sensitivity and specificity for identification of referral warranted disease. These results indicate that telemedicine may improve accessibility of ROP screening.

Thoracic epidural catheterization leading to delayed transient neurological symptoms with normal imaging findings

Paraparesis after epidural catheterization is rare but may be multifactorial. We report a case of temporary paraparesis in a 32-year-old female patient after thoracic epidural catheterization performed analgesia. A 16 G epidural needle was introduced at the T(7)-T(8) interspace but as frank blood came through, it was withdrawn and was reinserted at the T(8)-T(9) interspace. An 18 G epidural catheter was introduced and 10 ml of 0.125% bupivacaine with buprenorphine 150 mcg was given. Further top-ups were given for 48 h on complain of pain. There was an episode of hypotension after giving the epidural drug but later on the patient remained haemodynamically stable. On the fourth post-operative day, the patient reported paraparesis with heaviness and tingling sensation in both lower extremities. MRI was normal with no evidence of spinal cord compression, oedema, haematoma or abscess. The patient improved gradually within a period of 3 days. The possible causes of delayed onset of neurological symptoms are discussed.

Clinical outcomes after a diagnosis of brain metastases in patients with estrogen- and/or human epidermal growth factor receptor 2-positive versus triple-negative breast cancer

BACKGROUND

Women with triple-negative (TN) breast cancer are at increased risk of distant metastases and have reduced survival versus other breast cancer patients. Relative survival of women with TN breast cancer who develop brain metastases is unknown.

METHODS

Patients with breast cancer who developed brain metastases at our institution from 1993 to 2006 were reviewed. Four survival time intervals were compared in patients with TN disease and those with non-TN disease: initial diagnosis to distant metastases, distant metastases to brain metastases, brain metastases to death, and overall diagnosis to death.

RESULTS

One hundred and eighteen patients were identified. Fifty-one (50%) of 103 were estrogen receptor positive, 26 (39%) of 67 were human epidermal growth factor receptor 2 positive, and 20 (22%) of 91 were TN. Survival times were shorter for TN patients, with overall survival of 26 months in TN patients versus 49 months for non-TN patients. In TN patients, time to development of distant metastases, brain metastases, and death after brain metastases was shorter than in non-TN patients.

CONCLUSION

Patients with TN disease were more likely to develop distant metastases earlier than non-TN patients, developed brain metastases sooner, and had shorter overall survival.

Myopericytoma of neck region - A case report

A 42-year-old male presented with a history of an enlarging painless swelling on the right side of neck for 15 days. It recurred within three months of partial excision. Immunohistochemistry showed positivity for Smooth Muscle Actin [SMA]. This newly described entity is being reported for its unusual histological features and its differential diagnosis with other spindle cell and vascular lesions of soft tissues.

Implementation of a high-sensitivity Micro-Angiographic Fluoroscope (HS-MAF) for in-vivo endovascular image guided interventions (EIGI) and region-of-interest computed tomography (ROI-CT)

New advances in catheter technology and remote actuation for minimally invasive procedures are continuously increasing the demand for better x-ray imaging technology. The new x-ray high-sensitivity Micro-Angiographic Fluoroscope (HS-MAF) detector offers high resolution and real-time image-guided capabilities which are unique when compared with commercially available detectors. This detector consists of a 300 μm CsI input phosphor coupled to a dual stage GEN2 micro-channel plate light image intensifier (LII), followed by minifying fiber-optic taper coupled to a CCD chip. The HS-MAF detector image array is 1024×1024 pixels, with a 12 bit depth capable of imaging at 30 frames per second. The detector has a round field of view with 4 cm diameter and 35 microns pixels. The LII has a large variable gain which allows usage of the detector at very low exposures characteristic of fluoroscopic ranges while maintaining very good image quality. The custom acquisition program allows real-time image display and data storage. We designed a set of in-vivo experimental interventions in which placement of specially designed endovascular stents were evaluated with the new detector and with a standard x-ray image intensifier (XII). Capabilities such fluoroscopy, angiography and ROI-CT reconstruction using rotational angiography data were implemented and verified. The images obtained during interventions under radiographic control with the HS-MAF detector were superior to those with the XII. In general, the device feature markers, the device structures, and the vessel geometry were better identified with the new detector. High-resolution detectors such as HS-MAF can vastly improve the accuracy of localization and tracking of devices such stents or catheters.

Design and development of a mucoadhesive buccal film bearing progesterone

The purpose of this research was to develop and evaluate mucoadhesive films for buccal administration of progesterone using film-forming and mucoadhesive polymers. Buccal films of chitosan bearing progesterone were prepared by solvent casting technique. The films have been evaluated in terms of film weight, thickness, density, surface pH, FT-IR, X-ray diffraction analysis, bioadhesion, swelling properties, in vitro drug release and in vivo studies. It was found that the film formulations of 2 cm2 size having weight in the range of 239 +/- 0.32 to 290 +/- 3.23 mg and film thickness were in the range of 0.49 +/- 0.21 to 0.60 +/- 0.26 mm. Density of the films was found to be 0.108 to 0.139 g/mL. Drug content was found to be uniform in a range of 9.21 +/- 0.051 to 9.67 +/- 0.086 mg/cm2 for formulation F1 to F4. Maximum bioadhesion force was recorded for PVP buccal films (formulation F2) i.e. 0.45 +/- 0.53 N as compared to other films. In vitro residence time was in range of 1.85 +/- 0.08 to 8.94 +/- 0.08 h. The drug release studies revealed that formulations follows non-fickian diffusion. In vivo residence time data confirmed that none of the polymers detached from the oral mucosa over the study period, which indicated that the bioadhesion values of all polymers were satisfactory to retain the film on the buccal mucosa. These mucoadhesive formulations could offer many advantages in comparison to traditional treatments and their efficacy as an effective contraception is assessed.

Intra-operative 3D guidance in prostate brachytherapy using a non-isocentric C-arm

Intra-operative guidance in Transrectal Ultrasound (TRUS) guided prostate brachytherapy requires localization of inserted radioactive seeds relative to the prostate. Seeds were reconstructed using a typical C-arm, and exported to a commercial brachytherapy system for dosimetry analysis. Technical obstacles for 3D reconstruction on a non-isocentric C-arm included pose-dependent C-arm calibration; distortion correction; pose estimation of C-arm images; seed reconstruction; and C-arm to TRUS registration. In precision-machined hard phantoms with 40-100 seeds, we correctly reconstructed 99.8% seeds with a mean 3D accuracy of 0.68 mm. In soft tissue phantoms with 45-87 seeds and clinically realistic 15 degrees C-arm motion, we correctly reconstructed 100% seeds with an accuracy of 1.3 mm. The reconstructed 3D seed positions were then registered to the prostate segmented from TRUS. In a Phase-1 clinical trial, so far on 4 patients with 66-84 seeds, we achieved intra-operative monitoring of seed distribution and dosimetry. We optimized the 100% prescribed iso-dose contour by inserting an average of 3.75 additional seeds, making intra-operative dosimetry possible on a typical C-arm, at negligible additional cost to the existing clinical installation.

Acquired Blaschkoid dermatitis

Acquired Blaschkoid dermatitis characterised by unilateral relapsing inflammatory disease along the lines of Blaschko. A 40-year-old Indian male presented with unilateral erythematous, itchy grouped papules on the left side of the chest, abdomen, back and left arm of 15 days duration. The eruption stopped abruptly at the midline of the torso, completely sparing the right side of the body. The lesions were arranged in whorls and streaks corresponding to the lines of Blaschko. Skin biopsy showed hyperkeratosis and features suggestive of sub-acute spongiotic dermatitis with lymphocytic infiltrate around the blood vessels in the dermis. Patient was diagnosed as a case of Blaschkoid dermatitis. To the best of our knowledge, this is the first case of this condition being reported from India.

Living-donor liver transplantation in the United States: identifying donors at risk for perioperative complications

Donor safety has been scrutinized by both the medical community and the media. Variability exists in reported donor complications and associated risk factors are ill defined. Use of administrative data can overcome the bias of single-center studies and explore variables associated with untoward events. A retrospective cohort study identifying living liver donors in two large healthcare registries yielded 433 right and left lobe donors from 13 centers between 2001 and 2005. Perioperative complications were identified using International Classification of Diseases, 9th Revision (ICD-9) coding data and classified according to the Clavien system. Logistic regression models identified factors associated with complications. There was one perioperative death (0.23%). The overall complication rate was 29.1% and major complication rate defined by a Clavien grade >or=3 was 3.5%. Center living-donor volume (OR = 0.97, 95% CI = 0.95-0.99) and the ratio of living-donors to all donors (living and deceased) (OR = 0.94, 95% CI = 0.92-0.96) were associated with a lower risk of all complications. Donor age >50 years (OR = 4.25, 95% CI = 1.22-14.87) was associated with a higher risk of major complications. Living liver donation is currently performed with a low risk of major morbidity. Use of administrative data represents an important tool to facilitate a better understanding of donor risk factors.