Carbon nanotubes (CNTs) were discovered in 1991 and shown to have certain unique physicochemical properties, attracting considerable interest in their application in various fields including drug delivery. The unique properties of CNTs such as ease of cellular uptake, high drug loading, thermal ablation, among others, render them useful for cancer therapy. Cancer is one of the most challenging diseases of modern times because its therapy involves distinguishing normal healthy cells from affected cells. Here, CNTs play a major role because phenomena such as EPR, allow CNTs to distinguish normal cells from affected ones, the Holy Grail in cancer therapy. Considerable work has been done on CNTs as drug delivery systems over the last two decades. However, concerns over certain issues such as biocompatibility and toxicity have been raised and warrant extensive research in this field.Uniterms: Carbon nanotubes/properties. Carbon nanotubes/use/drugs delivery. Single-Walled Carbon Nanotube. Multiwalled Carbon Nanotube. Anticancer drugs/delivery. Cancer/therapy. Drugs/delivery.Os nanotubos de carbono foram descobertos em 1991 e suas propriedades físico-químicas únicas demonstradas, despertando interesse em sua aplicação em vários campos, incluindo a entrega liberação de fármacos. As propriedades únicas dos nanotubos de carbono, tais como a facilidade de captação pela célula, carga alta de fármaco, ablação térmica, entre outras, tornaram-nos úteis para terapia de câncer, uma das doenças mais difíceis dos tempos modernos, pois sua terapia envolve a distinção entre as células normais saudáveis e as afetadas pela doença. Os nanotubos de carbono têm um papel importante nessa área porque fenômenos como EPR permitem que estes possam distinguir as células normais das afetadas, que é o Santo Graal na terapia do câncer. Trabalho considerável tem sido feito ao longo das duas últimas década com nanotubos de carbono, como sistemas de liberação de fármacos. No entanto, preocupações sobre algumas questões, como biocompatibilidade e toxicidade, surgiram ao longo do tempo, demandando extensas pesquisa nesse campo. Unitermos: Nanotubos de carbono/propriedades. Nanotubos de carbono/uso/liberação de fármacos. Nanotubo de carbono de parede única. Nanotubo de parede múltipla. Fármacos anticancer/liberação. Cancer/tratamento. Fármacos/liberação.

Amongst the various routes of drug delivery, the field of ocular drug delivery is one of the most interesting and challenging endeavors facing the pharmaceutical scientist for past 10-20 years. As an isolated organ, eye is very difficult to study from a drug delivery point of view. Despite this limitation, improvements have been made with the objective of maintaining the drug in the biophase for an extended period. A major problem in ocular therapeutics is the attainment of an optimal drug concentration at the site of action. To achieve effective ophthalmic therapy, an adequate amount of active ingredient must be delivered and maintained within the eye. The most frequently used dosage forms, i.e., eye solution, eye ointments, eye gels, and eye suspensions are compromised in their effectiveness by several limitations leading to poor ocular bioavailability. Ophthalmic use of viscosity-enhancing agents, penetration enhancers, cyclodextrins, prodrug approaches, and ocular inserts, and the ready existing drug carrier systems along with their application to ophthalmic drug delivery are common to improve ocular bioavailability. Amongst these hydrogel (stimuli sensitive) systems are important, which undergo reversible volume and/or sol-gel phase transitions in response to physiological (temperature, pH and present of ions in organism fluids, enzyme substrate) or other external (electric current, light) stimuli. They help to increase in precorneal residence time of drug to a sufficient extent that an ocularly delivered drug can exhibit its maximum biological action. The concept of this innovative ophthalmic delivery approach is to decrease the systemic side effects and to create a more pronounced effect with lower doses of the drug. The present article describes the advantages and use stimuli sensitive of hydrogel systems in ophthalmic drug delivery.

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Background: Cancer is a condition in which some cells in the body grow uncontrollably, and can also spread and invade organs in other parts of the body. Among males, oral and lung cancer accounts for 25 % cancer deaths while in females, breast and oral cancer cause 25% death. Breast and cervical cancer are the underlying cause of the high mortality rate among women. Owing to limitations of conventional cancer therapy like low drug specificity, less solubility, Multidrug resistance, poor access to tumor cells, low bioavailability development of environmentally sensitive and target specific nanocarrier is imperative. Objective: To study advancements made in techniques to synthesize mesoporous silica nanoparticles (MSN’s) as well as strategies to functionalize its silanol group for site-specific drug release in the tumor environment and to review recent patents published regarding it. To describe rationale for selection of MSN’s for cancer theranostics amidst other nanocarriers developed. Methods: In the first section of this review, physical and chemical properties of MSNs making it an ideal delivery system for cancer therapy and diagnostics are discussed, in next section, various techniques involved in synthesizing and loading MSNs, including the influence of basic components of MSNs and reaction conditions on its properties are reviewed. Then the wide application of MSNs and various exogenous and endogenous stimuli harnessed for site-specific delivery of cargo and recent patents on modifying environmental conditions for large scale synthesis of MSNs and its active targeting for cancer treatment and bioimaging are discussed. Results: Physico-chemical properties and synthetic protocols of MSNs justifying them to be a promising nanovector to overcome the ill effects of traditional chemotherapy. The superlative attributes of MSNs including, tunable size, morphology, high load volume, stability, ease of modifying external and internal surface leverage applications in various dimensions of therapeutics, diagnostics, and combinatorial drug delivery. MSNs surface functionalization can be harnessed for passive and active targeting by either coating the surface with polymers or attaching various ligands. Conclusion: An ideal nano-carrier must have high loading efficiency, easily detectable, and must have stimuli's sensitive, site-specific drug release. The patent study explores new dimensions on MSNs synthesis by claiming new cost-effective templates and silica source, a more safe environment for synthesis, reducing synthesis steps, duration of reaction, effective loading of low solubility drugs by magnetized nanocarriers, pathogen-specific release and development of novel photoluminescent rechargeable MSNs under mild conditions. It’s a challenging task for researchers to successfully translate their prototypes to industries and make it feasible for commercialization. We can further work on excellent targeting concepts and architecture of MSNs for the increased opportunity in cancer theranostics.

Different barriers like a blood-brain barrier in the brain restrict the transport of potential therapeutic elements for direct entry into the brain. For delivery of a wide range of therapeutic drugs directly to the brain can be achieved by direct targeting the brain via an olfactory and trigeminal neural pathway which bypasses the blood-brain barrier hence has gained more importance and considered as an accurate route of drug targeting to brain. Intranasal route transports the drug by delivering it directly to the brain and avoiding the systemic absorption which also avoids the side effect of enhancing the efficacy of nano therapeutics. As these types of drug delivery commonly targeted drug delivery to the brain via nose are complex. Different strategies applied for overcoming these challenges has been covered. Drugs to be transported through this system are usually carried out through nano particulate system known as nanotechnology which helps in transportation of drug particles directly to the central nervous system and participates in drug release through a carrier-mediated system called nano particulate system have been extensively covered within the article. Parallel to this recent advancement in brain targeted drug delivery has been thoroughly explained and characterized. Although direct drug delivery to the brain is a vital challenge for researchers which can be overcome by using different types of strategies that have been covered under this article.

Objective: In the present study, the utilization of a novel biocompatible and biodegradable Methotrexate controlled release injectable formulation is established. The drug delivery vehicle used is an autogelling pH sensitive formulation, which is based on the natural biopolymer chitosan. Methods: Chitosan/glyceryl monooleate (C/GMO) solution was prepared in 0.33 M citric acid with gentle stirring. The weighed quantity of Drug and Chitosan in the required concentration was stirred with an appropriate quantity of 0.33 M Citric acid for 3 hours. Further, this solution was cooled to 4 o C. Then, to this cooled Chitosan and Drug solution, the desired amount of Glycerol Monooleate was added dropwise with constant stirring to obtain a clear homogenous system. Moreover, it was filtered by membrane filtration using the cellulose membrane. Finally, the prepared pH sensitive formulations were sterilized by autoclaving. Results: The drug release of the final formulation as cumulative percent drug release was found out to be 80.93%, 95.78%, 75.86%, 93.58% and 84.10% for formulation F1, F2, F3, F4 and F5 respectively after 8 hours. The in vitro drug release study had shown that the formulation F2 had better-sustained effect than other existing pH-induced formulations. Conclusion: All these findings showed that chitosan/GMO gel was found to be safe, effective, homogeneous and stable injectable formulation for sustained delivery of Methotrexate and presented an approach for the striking technology offering the platform for the delivery of other clinically significant anticancer drugs.