Development of starch-based pellets via extrusion/spheronisation.

A modified starch (high-amylose, crystalline and resistant starch) was evaluated as an alternative excipient to microcrystalline cellulose for pellets prepared via extrusion/spheronisation. Theophylline anhydrous (25%, w/w) was used as a model drug. A binder was necessary to obtain an acceptable yield and the addition of sorbitol improved the surface properties of the pellets. A surface response design with three formulation variables (binder, sorbitol and water level) and one process variable (spheronisation speed) was used to optimise the process and to evaluate pellet yield, sphericity (aspect ratio and two-dimensional shape factor, e(R)), size (mean Feret diameter), friability and disintegration properties. Mixer torque rheometry and solid-state NMR revealed a significant influence of sorbitol on wet mass consistency and pellet properties. A high pellet yield (>90%), acceptable sphericity (AR<1.2), low friability (<0.01%), fast disintegration (<10 min) and complete drug release in less than 20 min for all formulations, demonstrated the potential of this modified starch in formulations intended for extrusion/spheronisation.     

Immediate release of poorly soluble drugs from starch-based pellets prepared via extrusion/spheronisation.

The aim of this study was to evaluate modified starch (high-amylose, crystalline and resistant starch) as the main excipient for immediate-release pellets containing poorly soluble drugs (hydrochlorothiazide and piroxicam) and prepared via extrusion/spheronisation. The bioavailability of pellets (containing 50 mg hydrochlorothiazide) was determined after oral administration to 6 dogs. A 2(4)-factorial design with central point was used to evaluate the influence of hydrochlorothiazide (10% and 50%, w/w), HPMC (binder, 4% and 7%, w/w), sorbitol (0% and 10%, w/w) and water (granulation liquid, low and high level) on pellet yield, size (Feret mean diameter) and sphericity (aspect ratio and two-dimensional shape factor, eR). Optimal granulation liquid content depended on drug and sorbitol level in the formulation. All factors except sorbitol content, as well as the interactions between drug concentration and binder level and between drug and water level, were significant (P<0.05) for pellet yield, while a significant curvature (P<0.05) suggested non-linearity of the response plots. The model was not significant for pellet shape, while hydrochlorothiazide and water level as well as their interaction were significant (P<0.05) for pellet size. Pellet friability, disintegration, residual water content and in-vitro drug release were determined. Pellets containing 2.5% (w/w) piroxicam were also evaluated. For both model drugs, pellets with a high yield (>90%), acceptable sphericity (AR<1.2) and low friability (<0.01%) were obtained. Due to pellet disintegration, fast dissolution of both hydrochlorothiazide and piroxicam was achieved: >80% drug released in 30 min. The bioavailability (AUC0-->24 h, Cmax and tmax) of hydrochlorothiazide pellets in dogs was not significantly different from fast-disintegrating immediate-release hydrochlorothiazide tablets (P>0.05).     

Liver metastasis of a mucinous colonic carcinoma mimicking a haemangioma in T2‐weighted sequences

We report the case of a patient with a single liver metastasis of a mucinous colonic carcinoma that mimics a haemangioma in T2‐weighted sequences. Although a very high T2 signal in non‐cystic lesions is highly specific for the diagnostic of haemangioma, the use of gadolinium‐enhancement MRI is recommended. In patients with a history of neoplasia, the diagnosis of benign liver nodules should be made with caution.     

Visual impairment in severe and profound sensorineural deafness

The frequency of reversible and irreversible visual impairment was determined in children with severe and profound sensorineural deafness, as subnormal vision can adversely affect their educational and social development. Eighty three of 87 such children attending an audiology service were examined to assess the incidence and severity of visual impairment. Each child underwent a detailed ophthalmic assessment. The criteria for visual impairment were visual acuity < 6/9 Snellen or equivalent and/or abnormal binocular vision. Forty five had a normal ophthalmic examination (54.2%). Twenty nine had visual impairment (34.9%) and nine had ophthalmological abnormalities that did not interfere with vision (10.9%). A higher proportion of children with risk factors for visual pathology demonstrated visual impairment than those in whom there were no risk factors. None the less, 44% of visual impairment was among patients without risk factors. The results underline the need to examine all children with severe and profound sensorineural deafness soon after diagnosis and indicate that children with multiple handicaps have a greater likelihood of visual impairment (11 of 14 cases).     

Ultrasound screening of families with abdominal aortic aneurysm

Recent observations suggest that first degree relatives of patients with an abdominal aortic aneurysm (AAA) are also at risk for the development of this disorder. The first degree relatives of 130 adults with known AAA were invited to attend for an ultrasound examination. Fifty-two eligible relatives (mean age 53 years, range 41–73) from 38 families underwent sonographic screening. Using standard ultrasound criteria no participants were identified with an asymptomatic AAA. Thus, ultrasound of families of patients with AAA has a low yield and may not be useful for screening purposes.     

Continuous twin screw extrusion for the wet granulation of lactose

The purpose of this study was to examine and compare the powder and mechanical properties of different batches of low crystallinity powdered cellulose (LCPC-S1 to LCPC-S5) with those of commercial microcrystalline celluloses (MCC) (Avicel PH-101, Avicel PH-102, Avicel PH-103, Avicel PH-301, Avicel PH-302, and Emcocel 90m) and powdered celluloses (PC) (Solka Floc BW-40 and Solka Floc BW-100). Both the LCPC and MCC products were aggregated powders, whereas, the PC materials showed a fibrous structure. The primary particles forming the LCPC aggregates, however, were smaller in size and showed a greater degree of coalescence between boundaries, than those forming the MCC aggregates. The LCPC materials had significantly higher bulk and tap densities and lower porosity values compared with the MCC materials. The yield pressure value calculated from the linear region of the Heckel curve for LCPC varied between 48 and 70 MPa, for Avicel and PC materials between, 80 and 106 MPa, and for Emcocel 90m was 48 MPa. These results suggest that the LCPC products and Emcocel 90m, compared with commercial MCC and PC excipients, undergo plastic deformation at relatively lower compression pressures. The total volume reduction (i.e. compressibility), determined by calculating the area under the Heckel curve (AUHC), however, was comparable for all materials, with the exception of the LCPC-S3, which owing to the low yield pressure value, showed the largest reduction in volume. With the exception of LCPC-S1 and Solka Floc BW-40, all the other materials formed compacts, whose strength ranged from about 522 to 799 MPa2. The strengths of LCPC-S1 and Solka Floc BW-40 compacts, in contrast, were 214 and 257 MPa2, respectively. Irrespective of the solid fraction levels, the LCPC compacts, in general, disintegrated much faster than the MCC and PC compacts. In conclusion, the results suggest that the new LCPC materials reported herein have powder properties that are quite different from the MCC and PC materials evaluated, and show clear potential as direct compression excipients.     

In vitro evaluation of the quality of essential drugs on the Tanzanian market

We evaluated the in vitro availability and its stability under simulated tropical conditions of various formulations of four essential drugs marketed in Tanzania. We obtained 22 formulations (containing paracetamol, acetylsalicylic acid, chloroquine or sulphadoxine/pyrimethamine) from wholesale pharmacies in Dar es Salaam and the Medical Stores Department (Tanzania). The drug content, in vitro availability (dissolution) and its stability under simulated tropical conditions were determined using methods specified in the United States Pharmacopoeia (USP) 24 monograph of the respective drugs. All formulations passed the pharmacopoeia requirements for the drug content. However, seven formulations (three acetylsalicylic acid, two sulphadoxine/pyrimethamine and two paracetamol) failed to meet the USP 24 tolerance limits for dissolution. Another five formulations (three paracetamol and two chloroquine) failed to meet the dissolution tolerance limits after being subjected to an accelerated stability test under simulated tropical conditions (75% RH/40 degrees C) for 6 months. The study has demonstrated the presence on the Tanzanian market of essential drug formulations that met potency requirements and yet had unsatisfactory in vitro availability as they were not robust enough to withstand storage under simulated tropical conditions.     

Slug species- and population-specific effects on the end points of the Slug Mucosal Irritation test.

The Slug Mucosal Irritation test seems to be a promising method for the evaluation of the local tolerance of products applied to the mucosa. Furthermore, the Slug Mucosal Irritation test is a reliable method to classify chemicals accurately into three eye irritation categories based on the mucus production and the score for tissue damage. Until now the slug Arion lusitanicus collected in Belgium was always used as test organism. The present study investigated the effects of the slug population and species on the end points of the test and on the eye irritation classification. For this purpose, the eye irritation/damage test procedure and eye reference chemicals were used. Comparison of the results of one Belgian and two Swiss A. lusitanicus populations indicated that the geographic and ecological origins of slug populations did neither influence the mucus production, nor the score for tissue damage. Slug species-specific effects on the test end points were investigated by comparing the data of Belgian Limax flavus with corresponding data of Belgian A. lusitanicus. L. flavus produced more mucus than A. lusitanicus, so that the mucus production cut-off values had to be increased. Therefore, the results indicated that the test procedure and prediction model have to be optimised and validated, if other slug species are used instead of A. lusitanicus.