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Intestinal permeation enhancers (PEs) are key components in ∼12 oral peptide formulations in clinical trials for a range of molecules, primarily insulin and glucagon-like-peptide 1 (GLP-1) analogs. The main PEs comprise medium chain fatty acid-based systems (sodium caprate, sodium caprylate, and N-[8-(2-hydroxybenzoyl) amino] caprylate (SNAC)), bile salts, acyl carnitines, and EDTA. Their mechanism of action is complex with subtle differences between the different molecules. With the exception of SNAC and EDTA, most PEs fluidize the plasma membrane causing plasma membrane perturbation, as well as enzymatic and intracellular mediator changes that lead to alteration of intestinal epithelial tight junction protein expression. The question arises as to whether PEs can cause irreversible epithelial damage and tight junction openings sufficient to permit co-absorption of payloads with bystander pathogens, lipopolysaccharides and its fragment, or exo- and endotoxins that may be associated with sepsis, inflammation and autoimmune conditions. Most PEs seem to cause membrane perturbation to varying extents that is rapidly reversible, and overall evidence of pathogen co-absorption is generally lacking. It is unknown however, whether the intestinal epithelial damage-repair cycle is sustained during repeat-dosing regimens for chronic therapy.

Glioblastoma multiforme (GBM) is the most aggressive brain tumor. Standard treatment includes surgery, radiation and chemotherapy. Prognosis is dismal with an average survival of approximately 1 year. Gliadel wafers are one treatment option, working as a source for local chemotherapy delivery. Their use is controversial with questionable survival benefit and potential side effects. We reviewed the literature in an effort to clarify their role in the treatment of high-grade gliomas. A systematic PubMed search was performed using the keywords 'Gliadel', 'carmustine' or 'BCNU wafers' in newly diagnosed high-grade glioma patients. Treatment regimen, and median survival were analyzed. Adverse event ratio was calculated by computing the number of adverse events in a study per patient receiving carmustine wafers. Nineteen studies with 795 patients were included in our review. Survival was 8.7-22.6 months with a mean overall survival (OS) of 16.2 months (control survival is approximately 14 months with surgery and adjuvant chemoradiotherapy). Adverse event ratio using Gliadel wafersin control group. Complication rate was 42.7%. Gliadel wafers may marginally increase survival and local control in newly diagnosed GBM patients but are associated with a high complication rate; therefore, we do not recommend using Gliadel wafers in patients with GBM. Further research may be warranted once a safer alternative to Gliadel wafers has been introduced.

Objective: The prognosis of high-grade glioma (HGG) is poor with a median survival of about 1 year for glioblastoma. In 2007, NICE published a technology appraisal (TA121) recommending the use of carmustine wafers (Gliadel) and systemic therapy with temozolomide for selected patients with HGG. Outcomes for HGG surgery in the United Kingdom with these combined treatments have not been published., Design: Retrospective audit of consecutive patients in a single unit with carmustine wafer implantation., Subjects: Fifty-nine patients had carmustine wafers implanted at primary surgery, between October 2005 and October 2010 at Wessex Neurological Centre, Southampton, UK., Methods: Patients were given chemotherapeutic treatments strictly according to NICE TA121. Survival was calculated using Kaplan-Meier method., Results: Fifty-five patients had WHO grade IV tumours and four had grade III. Median age was 61 years. At follow-up, 39 patients had died. Median survival was 15.3 months. Eight patients (13.5%) experienced post-operative complications (including five infections) for which four had the carmustine wafers removed. Forty-seven (80%) patients were treated with radical radiotherapy (55-60 Gy) and six (10%) patients received palliative radiotherapy (30 Gy). Thirty-seven patients (63%) received concomitant temozolomide chemotherapy. In the subset of 37 patients receiving multimodal treatment with radical radiotherapy and concomitant temozolomide, median survival was 15.8 months compared with 7.4 months in those not receiving multimodal treatment., Discussion: Carmustine wafers for primary HGG surgery in accordance with the NICE TA121 were associated with a median survival of 15.3 months; this is improved compared with previously reported randomised trials. Multimodal treatment with carmustine wafers, radical radiotherapy and concomitant temozolomide was associated with improved survival. Increased incidence of infections was observed in cases receiving carmustine wafers.