Formulation and evaluation of a colon drug delivery system containing diflunisal

Oral drug delivery is the most desirable and preferred method of administering therapeutic agents for providing both systemic and local effects in various parts of the gastrointestinal tract. Recently, greater emphasis has been placed on controlling the site and/or rate of drug release from oral formulations to improve treatment efficacy and patient compliance. Many novel oral drug therapeutic systems have been invented like fast release, targeted release and colon specific drug delivery systems etc... During the last decade there has been an interest in developing site specific formulations for targeting to the colon. The delivery of drugs to the colon has a number of therapeutic implications in the field of drug delivery. Localized delivery of the drugs in the colon is possible only when the drug is protected from the hostile environment of upper GIT. The various approaches that can be exploited to target the release of drug to colon include prodrugs, coating with pH sensitive polymers, coating with biodegradable, timed release systems, osmotic and bioadhesive polymers. In the present study, solid dispersions of pH-dependent, time dependent and combined pH and time-dependent systems were formulated using Eudragit RS100, Eudragit S100, Eudragit L100 and ethylcellulose, with different drug-to-polymer ratios. They were evaluated for their in-vitro release characteristics in an attempt to develop a colon-specific delivery system containing Diflunisal. Release studies of Diflunisal and Diflunisal solid dispersion systems with different polymers were employed using Release apparatus, USP [paddle type] [copley, England] showed that, the combination of pH- and time-dependent systems provided better results than the pH-dependent or the time dependent system alone. Using Eudragit S100 and Eudragit RS100 with Diflunisalin a ratio 2:3:1, respectively for preparing a solid dispersion used for developing a colon-specific delivery system of Diflunisal was the most successful formula. This formula released 0.22 +/- 0.03% of the drug included in it in the stomach pH and 26.29 +/- 0.91% of the drug in the intestine pH and 77.59 +/- 1.79% of the drug in the colon pH

Physical and psychological study of different presentations of rheumatic fever and pediatric autoimmune neuropsychiatric disorders after streptococcal infection

A recent line of research has suggested that autoimmune-mediated central nervous system manifestations of Group A-beta hemolytic streptococcal [GABHS] infection may not be restricted to Sydenham chorea [SC] but may include a range of neurobehavioral disturbances that has been termed pediatric autoimmune neuropsychiatric disorder after streptococcal infection [PANDAS]. To clarify the clinical link between rheumatic fever and its variant rheumatic chorea and PANDAS. This study was done on 86 children. Their ages ranged from 5 to 15 years. They were among the patients admitted to the Pediatric Department, Tanta University Hospital. They were classified into 5 groups: [A] Six patients with PANDAS, [B] Twenty rheumatic chorea patients, [C] Twenty children with non-choreic rheumatic fever, [D] Twenty patients with recent GABHS infection, and [E] Twenty healthy children as controls. They were subjected to history taking, clinical examination and psychiatric and psychometric assessment. Serum samples were taken for the following laboratory investigations: CBC, ESR, ASOT and CRP. The children were also subjected to ECG and X-ray chest and heart in addition to colored echo-Doppler examination. A significant increase in psychiatric manifestations was found in rheumatic chorea. Great similarities between PANDAS and rheumatic chorea patients were found as regard physical, psychiatric and laboratory findings. Both PANDAS and SC had no significant differences as regards prevalence or the type of psychiatric manifestations. Psychiatric manifestations should be looked for in rheumatic patients. Assessment of psychiatric patients for possible early presentation of rheumatic fever should be done. PANDAS should be studied in further researches to detect epidemiology and relation to rheumatic fever and SC