ABSTRACT
This review highlights the characteristics of the cancer that provide opportunities for drug delivery carriers to target cancer. These opportunities include EPR effect, high interstitial pressure of tumour, low pH of endosomes of tumor cells, overexpressed receptors, angiogenesis etc. Chemotherapy is one of the most important treatments currently available among the various approaches. The present status of chemotherapy is far from being satisfactory. Its efficacy is limited and patients have to suffer from serious side effects, some of which are life-threatening. The newer approaches to cancer treatment not only supplement the conventional chemotherapy but also aim to prevent damage to the normal tissues and overcome drug resistance. The innovative approaches of cancer treatment require new concepts of drug delivery in cancer. This concept requires the unique surface morphology which ultimately determines the fate of new drug delivery systems. The Innovative methods must also shoot out the associated problems of cancer like multidrug resistance by tumor cells. Progress in developing various controlled and targeted drug delivery systems has reviewed here with an emphasis on dendrimeric drug delivery system. Dendrimeric system appears to be promising in cancer chemotherapy especially via ligand/receptor mediated endocytosis as it posses numerous properties (especially surface property) to target cancer.
ABSTRACT
Metformin hydrochloride is recommended globally as first line therapy due to its favorable profile on morbidity and mortality associated with type-2 diabetes mellitus. However, limitations of multiple dosing and risk of triggering gastrointestinal symptoms make its dose optimization difficult. Extended-release metformin matrix tablets were prepared by direct compression of drug and different pH-dependent (Eudragit L-100 and S-100) and pH-independent (Eudragit RLPO and RSPO) polymer combinations. The influence of varying the polymer/polymer (w/w) ratio was evaluated. Among the different examined polymer blends, matrix tablets based on S-100/RLPO and S-100/RSPO mixtures gave the more sustained release pattern. The excipients used in this study did not alter physicochemical properties of the drug, as tested by Fourier transform Infrared Spectroscopy and the thermal analysis using differential scanning calorimetry. All the batches were evaluated for thickness, weight variation, hardness, and drug content uniformity. The in vitro drug dissolution study was carried out using USP 22 apparatus II, paddle method and the release mechanisms were explored. Mean dissolution time is used to characterize drug release rate from a dosage form and indicates the drug release retarding efficiency of polymer. Kinetic modeling of in vitro dissolution profiles revealed the drug release mechanism ranges from diffusion controlled to anomalous type. Fitting the data to Korsmeyer equation indicated that diffusion along with erosion could be the mechanism of drug release.