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Biomedical subjects

B Conti

Publications and source records attributed to B Conti.

84 records · Page 5Linked to original sources
PubMedDate not supplied

Cellulose acetate trimellitate ethylcellulose blends for non-steroidal anti-inflammatory drug (NSAID) microspheres.

Ketoprofen (Ket), a non-steroidal anti-inflammatory drug, has been incorporated into polymeric micromatrices (microspheres) prepared by a spray drying process and made of cellulose acetate trimellitate (CAT)/ethylcellulose (EC) blends. Drug loaded microspheres were obtained by spray-drying organic solutions of the two polymers and the drug. Characterization of the microparticles (morphology, particle size distribution, drug content, yield of production, surface properties, solvent residues) was carried out and in-vitro release behaviour measured. The release rate of the drug diminished as the proportion of EC was raised.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMedDate not supplied

Evaluation of process parameters involved in chitosan microsphere preparation by the o/w/o multiple emulsion method.

Chitosans are interesting biopolymers largely studied for applications in the medical and pharmaceutical fields. In this work, an o/w/o multiple emulsion technique was used for the preparation of hydrophobic drug loaded microspheres. Moreover, the influence of critical variables (concentration of acetic acid in the polymer solution and drug-polymer ratio) on microsphere morphology and drug content was evaluated. Two chitosans of different molecular weights and deacetylation degree were employed; ketoprofen, a non-steroidal anti- inflammatory drug, was chosen as the hydrophobic model drug. The multiple emulsion method produced well-formed microspheres with good yields. Acetic acid concentration in the polymeric solutions influenced particle size and drug content of the microspheres. The highest drug encapsulation efficiencies were obtained for the lowest theoretical drug/chitosan ratio.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMedDate not supplied

Thymopentin loaded microsphere preparation by w/o/w emulsion technique: in vitro/ex vivo evaluation.

Poly-D,L-lactide (PDLLA) and polylactide-co-glycolide (PLGA) microspheres containing thymopentin have been prepared by a water-in-oil-in-water-emulsion/solvent evaporation technique. The goal is to stabilize the active compound thymopentin, and to prolong its therapeutic activity, by embedding the drug in a polymeric matrix. The microspheres obtained have been characterized for their morphology and drug content. In-vitro dissolution tests have been performed on the microspheres. Results show that the type of polymer employed (PDLLA or PLGA) does not seem to affect microsphere morphology, while in-vitro dissolution profiles are greatly influenced by the composition of polymer matrix. Ex-vivo evaluation of PLGA microspheres performed on mouse thymocites shows that biological activity of Thymopentin is maintained after loading into PLGA microspheres.

Adjuvants, Immunologic↗
PubMedDate not supplied

Hyaluronidase-injectable microparticles intended for the treatment of extravasation.

Hyaluronidase is a protein whose enzymatic activity is successfully employed in extravasation therapy. Taking into account that several proteins (e.g. gelatin and albumin) have been employed as natural polymers for the preparation of microspheres, this work approaches a comprehensive investigation on hyaluronidase injectable microparticles. The goals are either to obtain a sustained release preparation of hyaluronidase or to use the enzyme as drug carrier. Microspheres have been prepared using a water-in-oil emulsification technique, and they have been crosslinked either by thermal or chemical means. Results show that hyaluronidase microspheres with good morphological characteristics can be obtained by this preparation method. Manufacturing variables influence the enzymatic activity of the microspheres, which can be highly preserved under mild experimental conditions. Moreover, the suitability of this enzyme as a microparticulate drug carrier has been shown by the successful encapsulation of hydrocortisone sodium succinate.

Animals↗
PubMedDate not supplied

Clonazepam microencapsulation in poly-D,L-lactide-co-glycolide microspheres.

The work is aimed at the preparation and characterization of biodegradable microspheres of poly-D,L-lactide-co-glycolide (PLGA), for the controlled release of clonazepam. The solubility characteristics of this drug make it an interesting example to evaluate the performances of the two most widely used microencapsulation techniques, emulsification solvent evaporation and spray-drying. Several biodegradable PLGA copolymers have been evaluated (RG 502H, RG 503H, RG 503, Boerhinger Ingelheim). They differ in terms of molecular weight and physico-chemical characteristics. The microspheres obtained have been characterized for their morphology, physico-chemical properties (DSC) and in vitro dissolution behaviour. Between the two preparation methods, only spray-drying was suitable for the microencapsulation of clonazepam in PLGA microspheres. In vitro dissolution tests highlight that more sustained release of drug is achieved with the higher (molecular weight) polymer.

Anticonvulsants↗
PubMedDate not supplied

Polylactide microspheres for the modified release of corticosteroids.

A steroidal drug, prednisolone 21-acetate, has been incorporated into polylactide (PDLLA) microspheres using a single emulsion/evaporation technique. This paper describes the method used and the characterization of the microspheres obtained: morphology, particle size distribution, drug content, yield of production and in vitro drug release behaviour.

Adrenal Cortex Hormones↗
PubMedDate not supplied

[Pulmonary metastasis of basal cell carcinoma of the skin. 3 case reports].

The Authors describe three cases of lung metastasis from a basal cell carcinoma of the skin observed in the Department of Thoracic Surgery of the National Cancer Institute in Milan. The incidence of this rare occurrence reported in the literature is approximately 0.1%, The aim of the study was to evaluate the therapeutic treatment adopted in these unusual situations. In all cases the primary basal cell carcinoma of the skin was located in the head. All three patients had several local and regional recurrences and underwent multiple surgical excisions and subsequent plastic procedures. In each case complementary radiotherapy was implemented. The metastases appeared in the lung 9, 17 and 21 years, respectively, after onset of the primary tumour as bilateral nodules in two cases and as a single nodule in one. Curative surgery was possible only in one subject, consisting in a bilateral metastasectomy via a midline sternotomy, with 5-year survival. Surgery was withheld in the other two subjects owing to advanced age and the presence of bilateral nodules with concomitant bone metastasis, respectively. Both were treated by chemotherapy and the patient with synchronous bone metastasis also received radiotherapy. The elderly subject died after six months, and the other patient after 19 months despite partial remission of disease. In our experience, curative therapy proves difficult due to multiple metastases. In the literature there are few reports regarding this rare type of metastatic lung disease, but surgical intervention would appear to be the therapy offering the best chance of long-term survival while chemotherapy constitutes the second-choice treatment.

Aged↗
PubMedDate not supplied

[Surgery in the treatment of metachronous homolateral non-small cell lung cancer].

The authors describe their experience with the surgical treatment of metachronous homolateral lung cancer by completion pneumonectomy. In the Department of Thoracic Surgery of the National Cancer Institute of Milan, over a period ranging from 1982 to 1996, 30 completion pneumonectomies were performed for local relapses or second primary tumors. The patients submitted to this intervention had a lobectomy as their first operation in 23 cases (77%), a bilobectomy in 4 (13%) and a typical segmentectomy in 3 (10%). Associated with these interventions we performed 2 en bloc chest wall resections and a contralateral wedge resection. Two subjects received neoadjuvant chemo-therapy. Histology revealed squamous carcinoma in 14 cases (47%) and adenocarcinoma in 16 (53%). Seventeen patients (57%) were classified as stage I, 8 as stage II (26%), 4 as stage III (13%) and 1 as stage IV (4%). Four patients received adjuvant chemotherapy and/or radiotherapy. Lung cancer relapse occurred as a single lesion in 27 cases (90%) and as multiple lesions in 3 (10%). We performed 18 right (60%) and 12 left (40%) completion pneumonectomies. In 1 case (4%) a sleeve pneumonectomy was necessary. Associated with these interventions we performed 5 en bloc chest wall resections. The perioperative mortality was 10% and the postoperative morbidity 40%. Histological tests showed 12 squamous carcinomas (40%) and 18 adenocarcinomas (60%). Two patients (7%) had a different histology. Disease was classified as stage I in 13 cases (44%), as stage II in 9 (30%) and as stage III in 8 (26%). Four patients received adjuvant chemotherapy and/or radiotherapy. Two subjects developed a metachronous contralateral tumor (7%). The disease-free interval was 22.70 +/- 14.69 months, with a median value of 17 months (range: 7-53 months). Mean survival after completion pneumonectomy was 49.77 +/- 49.29 months, with a median value of 26.5 months (range: 4-190 months). The 5-year actuarial survival rate, calculated using the Kaplan-Meier method, was 30%. Completion pneumonectomy is a technically very demanding intervention carrying a high risk of morbidity. On the basis of the analysis of our data, we can affirm that mean postoperative survival seems to be satisfactory and to justify this aggressive attitude towards recurrent tumor. We should stress the importance of careful evaluation of indications and precise selection of patients.

Adult↗
PubMedDate not supplied

[Significance of video-assisted thoracoscopic surgery in the diagnosis and staging of primary pulmonary neoplasms].

The authors describe the usefulness of video-assisted thoracoscopic surgery (VATS) in the staging and diagnosis of primary lung cancer. In the Oncological Thoracic Surgery Department of Milan's National Cancer Institute, over the period from January 1995 to January 2000, 46 patients, suspected of having mediastinal lymphadenopathies in the presence of lung cancer, were proposed for a VATS biopsy. Forty-four patients underwent a thoracoscopic lymph node biopsy (95%), while in 2 subjects, in whom pleural metastases were found, the histological diagnosis was established by pleural metastatic nodule thoracoscopic biopsy (5%). A VATS lymph node biopsy was performed in 16 cases at level 5 (35%), in 13 at level 6 (28%), in 9 at level 7 (19%) and in 6 at level 8 (13%). Lymph node biopsies were ipsilateral in 37 patients (80%) and contralateral in 7 (15%). No postoperative complications were observed. Histological examination revealed adenocarcinoma in 23 cases (50%), epidermoid carcinoma in 12 (26%), microcytoma in 8 (17%) and giant-cell lung carcinoma in 3 (7%). Two patients were classified as stage IV (5%), 7 as stage III B (15%) and 21 as stage III A (45%). The subsequent treatment was neoadjuvant chemotherapy for stage III A patients and chemotherapy in association with radiotherapy for stage III B subjects. The patients with microcytoma underwent integrated radiotherapy and chemotherapy and pan-encephalic radiotherapy. Sixteen patients, with negative frozen-section histological findings for mediastinal lymph node neoplastic disease, underwent pulmonary resection after thoracotomy in the same operating session (35%) and were subsequently classified as stages I and II. In conclusion, VATS proved extremely useful in the diagnosis and staging of patients affected by lung cancer with synchronous lymph node enlargement. This procedure allowed the diagnosis of suspect involved mediastinal lymph nodes in all cases thus affected and the exclusion of lymph node disease in patients subsequently treated by lung resection in a single session. The precise staging obtained then made it possible to direct the patients towards the most appropriate form of treatment.

Adult↗
PubMedDate not supplied

[Analysis and long-term survival in sternectomy with plastic reconstruction for primary and secondary neoplasms of the sternum].

From January 1980 to December 1999, 88 patients underwent surgical resection for tumours involving the sternum. Thirty were males, aged 16 to 76 years, and 58 females, aged 23 to 78 years (mean ages: 48 and 53 years, respectively). There were 30 primary malignant tumours, 28 local recurrences or distant metastases from breast cancer, 16 other tumours, and 14 radionecroses. Total sternectomy was performed in 8 cases, subtotal (> 50%) in 32, and partial (< 50%) in 48. Concurrent en-bloc resection of the anterior ribs was performed in 61 patients, and of the clavicle in 13. Resection was extended to the lung in 22 patients, to the pericardium in 17, to both in 2, to the diaphragm and pericardium in 4. Bone and soft tissue defects were repaired with prosthetic material associated with a muscular or myocutaneous flap in 55 patients, with prosthetic material alone in 13 cases, with a muscular or myocutaneous flap in 5 cases, and with other techniques in the remaining patients. The resection was considered to be macroscopically radical in 78 patients and palliative in 10 cases. There was one perioperative mortality and significant morbidity was limited to 13 cases. Among the patients treated with a radical intent, 48 were alive and disease-free at the end of follow-up. The 10-year survival rate was 85% in primary tumours. For breast cancer relapses, 10-year survival was the same as 5-year survival (41.8%). In our experience, an en-bloc sternal resection for a primary or secondary tumour, followed by plastic repair using prosthetic material and/or a myocutaneous flap, is a safe, effective treatment. This intervention permits the execution of extensive radical resections for sternal neoplasms, as well as enabling the patient to obtain a better quality of life. Long-term survival after radical sternectomy also depends on the histological type of the tumour.

Adolescent↗
PubMedDate not supplied

Cleanliness assessment of supplier-cleaned stoppers.

The particulate levels found on supplier microcleaned rubber closures were compared to those of stoppers processed by a pharmaceutical manufacturer. The particle monitoring was performed using two official compendial methods: light blockage using a HIAC/ROYCO counter, and optical microscopy using a polarizing research microscope. The supplier-microcleaned stoppers were found to contain relatively few particles per stopper by both instrumental and microscopic counting. The cleaning process used by the pharmaceutical manufacturer was effective in reducing the particle load on their stoppers by factors of 2 to 20 fold as compared to the unwashed stoppers for the different size ranges measured. However, the supplier-microcleaned stoppers were found to be cleaner than those processed by the pharmaceutical manufacturer by a factor of 10 to 20 times for particle sizes greater than 10 microns using the instrumental method. Differences in the counts by microscopic and light blockage methods were attributed to the sampling and agitation procedures. Both the supplier-microcleaned and manufacturer's processed closures were found to meet the USP XXI limits for allowable particulate contamination in small volume parenterals.

Drug Contamination↗