Current pharmaceutical strategies for efficient site specific delivery in inflamed distal intestinal mucosa.

Inflammatory bowel disorder is associated with certain pathophysiological disturbances which make established techniques of colon targeting more complex and inconsistent. Probable reason is severity of inflammation which leads to more variability in normal range of triggering factors that are being exploited for colon targeting. Influential changes in pathophysiology of intestine during inflammatory bowel disorder including Crohn's disease and ulcerative colitis both in active as well as quiescent stage have been discussed. Also the potential of various drug delivery techniques used both orally and rectally for site specificity have been summarized in inflammatory bowel disorder. Colon targeting surely has additional advantages in drug delivery specifically for the effective treatment of local pathologies. Colon targeting in IBD state demands exhaustive cognizance about the triggering conditions responsible for activation of drug release in IBD. Therefore despite the modern techniques exploited for colonic delivery, the effective management of IBD needs additional efforts and improvisation in developing precise colonic drug delivery system in inflamed bowel. Among all investigated techniques for colon delivery in IBD, pH based system is found to be more effective in targeting colon which has been vindicated by various clinical studies. In this review various pharmaceutical strategies have been covered which have been exploited clinically for the management of inflamed intestinal conditions.

Carbon nanotubes: a potential concept for drug delivery applications.

The unique properties of carbon nanotubes (CNTs) make them a highly interesting and demandable nanocarrier in the field of nanoscience. CNTs facilitate efficient delivery of therapeutics like drugs, proteins, genes, nucleic acids, vitamins and lot more. Even though highly beneficial, the biocompatibility of CNTs is a major issue in their questioning their potential application in targeting drug delivery. Studies confirmed subdued toxicity of CNTs following slight modifications like functionalization, controlled dimensions, purification etc. A well-established mechanism for cellular internalization is an insistent need to attain a more efficient and targeted delivery. Recent patents have been thoroughly discussed in the text below.

Terminalia gum as a directly compressible excipient for controlled drug delivery.

The exudates from the incised trunk of Terminalia randii has been evaluated as controlled release excipient in comparison with xanthan gum and hydroxypropylmethylcellulose (HPMC) using carvedilol (water insoluble) and theophylline (water soluble) as model drugs. Matrix tablets were prepared by direct compression and the effects of polymer concentration and excipients-spray dried lactose, microcrystalline cellulose and dicalcium phosphate dihydrate on the mechanical (crushing strength (CS) friability (F) and crushing strength-friability ratio (CSFR)) and drug release properties of the matrix tablets were evaluated. The drug release data were fitted into different release kinetics equations to determine the drug release mechanism(s) from the matrix tablets. The results showed that the CS and CSFR increased with increase in polymer concentration while F decreased. The ranking of CS and CSFR was HPMC > terminalia > xanthan while the ranking was reverse for F. The ranking for t(25) (i.e. time for 25% drug release) at a polymer concentration of 60% was xanthan > terminalia = HPMC. The dissolution time, t(25), of theophylline matrices was significantly lower (p < 0.001) than those of carvedilol matrix tablets. Drug release from the matrices was by swelling, diffusion and erosion. The mechanical and drug release properties of the tablets were significantly (p < 0.05) dependent on the type and concentration of polymer and excipients used with the release mechanisms varying from Fickian to anomalous. Terminalia gum compared favourably with standard polymers when used in controlled release matrices and could serve as a suitable alternative to the standard polymers in drug delivery.