Recent Patents on Drug Delivery & Formulation - Volume 10, Issue 1, 2016

Cancer is a major malignancy which has claimed numerous lives worldwide. Despite huge resources being utilized to develop cancer therapeutics, no effective cure has been found so far. Hence there is a need to look at emerging technologies for a solution. Nanoparticle is one such technology that has become feasible and popular in the past few years. Though, it has not emerged as a drug delivery platform of choice for cancer therapeutics it has shown enormous promise. Different types of materials such as polymer, lipid, magnet, metal based nanoparticles have been developed to enhance the effectiveness of current treatment. This manuscript will review different aspects of nanoparticles and recent research advances and patents for treatment of cancer.

Typically, chemotherapy has been dominated by intravenous administration. Though, inclination towards oral ingestion of chemotherapeutics is increasing since it offers ample of fascinating opportunities including better quality of life, treatment advantages and low healthcare cost. However, low or moderate bioavailability along with significant inter-patient variability and narrow therapeutic window challenges their oral administration. Thus, optimization of oral route with maximized efficacy and miniminal adverse events is a challenging area. To surmount the challenges, a number of strategies like P-glycoprotein (P-gp) modulation, colloidal carrier etc. have been under investigation and scientists are exploring the utility of solid dispersions, prodrugs, biconjugates, complexes, microparticulate, and nanoparticulate systems (liposome, SLN, dendrimers, SEDDS, nanoparticles). Among these, nanoparticulate systems have shown promising results due to their targeting potential and ability to alter absorption pathways. Functional excipients with P-gp modulating activity are also being explored for more effective oral delivery of chemotherapeutics. This article explores the encouraging reports, recent patents and inventions on the feasibility and applicability of oral administration of chemotherapeutics.

Natural diterpenoid taxanes and their semisynthetic analogues have already made an indelible mark in the chemotherapeutic world for treating various kinds of malignancies. However, due to the absence of any functional groups which could be ionized by pH alteration or which may participate in salt formation, these taxanes, exhibit low solubility. Parenteral administration of taxanes with solubilising agents such as Cremophor EL and Polysorbate 80 results in undesirable side effects like hypersensitivity reactions, myelosuppression and peripheral neuropathy. Nanoengineered drug delivery systems like nanoemulsions, nanocrystals, dendrimers, micelles, selfnanoemulsifying systems, liposomes, solid-lipid nanoparticles and biodegradable polymeric nanoparticles, in this regard, tend to surmount these ostensible challenges, when administered orally. The bare taxanes encounter several inadequacies, namely poor aqueous solubility, structural instability in physiological fluids, p-glycoprotein recognition, hepatic first-pass effect, gastrointestinal permeability, and Cytochrome P450 enzymatic metabolism, etc. In addition, nanoscaled oral delivery improves drug encapsulation, thus facilitating diffusion through intestinal epithelium, modification of pharmacokinetic and tissue distribution profile of the drug, eventually resulting in flexibility of dosing schedules, prevention of discomfort of the injection and hospitalization, and improved patient convenience. The current review paper endeavors to provide a bird’s eye view on the significant headway made on orally-administered nanosystems of taxanes and their analogues through patent applications published till date since its discovery.

Researchers are facing challenges to develop robust formulation and to enhance the bioavailability of poorly water-soluble drugs towards clinical applications. The development of new drug molecule alone is not adequate to assure ample pharmacotherapy of various diseases. Considerable results obtained from in vitro studies are not supported by in vivo data due to inadequate plasma drug concentrations. This may occur due to limited drug solubility and absorption. To resolve these problems, development of new drug delivery systems will be a promising approach. One of the promising pharmaceutical strategies is the use of lipospheres drug delivery system to deliver the poorly water-soluble drugs. Therefore, the present review described the methodology for manufacturing of lipospheres and factors influencing the formulation to deliver the drugs to the targeted site. Apart from that, this review also enlisted briefly the various applications of liposphers in medical and biomedical fields and critically discussed the recent patent system.

Natural antioxidant products are increasingly being used to treat various pathological liver injuries considering the role of oxidative stress in their pathogenesis. Auricularia polytricha has been used as food or medicine due to its antioxidant activity. The aim of the study was to evaluate the protective effect of the aqueous extract of the fruiting bodies of A. polytricha against paracetamol-induced liver toxicity in rats. Liver toxicity was induced in Sprague–Dawley rats by oral administration of 2g/kg paracetamol on the 15th day after the administration of aqueous extract and silymarin 100 mg/kg. Aqueous extract of A. polytricha was administered orally at 250 and 500 mg/kg doses, daily for a period of 14 days. Aspartate aminotransferase (AST), Alanine transaminase (ALT) and Alkaline phosphatase (ALP), Lactate dehydrogenase (LDH), Total bilirubin (TB), Total protein (TP), Triglycerides (TG) and cholesterol were measured to assess the effect of the extract on paracetamol-induced hepatic damage. The patent on Auricularia Polytricha (EP0413052A1) assisted in selecting the extraction procedure. The study also included histopathological examination of liver sections to assess hepatoprotective activity. Paracetamol significantly (P<0.001) increased the serum AST, ALT, ALP, LDH, TB, TG and cholesterol and decreased TP levels. Extract treatment significantly (P<0.001 to P<0.05) attenuated the paracetamol induced increase in AST, ALT, ALP, LDH, TB, TG and cholesterol and increased the diminished TP in a dose dependent manner. The standard drug, silymarin produced significant (P<0.001) decrease in AST, ALT, ALP, LDH, TB, TG and cholesterol and increase in TP. Histopathological examination of animals treated with paracetamol showed large areas of centrilobular necrosis with congestion and dilatation in both central and portal veins. These results indicate that the aqueous extract of A. polytricha has significant protective effect against paracetamol-induced liver toxicity in rats, due to its potent antioxidant activity.