Cyclodextrins (CDs) are a family of cyclic oligosaccharides with a hydrophilic outer surface and a lipophilic central cavity. CD molecules are relatively large with a number of hydrogen donors and acceptors and, thus in general, they do not permeate lipophilic membranes. In the pharmaceutical industry, CDs have mainly been used as complexing agents to increase aqueous solubility of poorly soluble drugs and to increase their bioavailability and stability. CDs are used in pharmaceutical applications for numerous purposes, including improving the bioavailability of drugs. Current CD-based therapeutics is described and possible future applications are discussed. CD-containing polymers are reviewed and their use in drug delivery is presented. Of specific interest is the use of CD-containing polymers to provide unique capabilities for the delivery of nucleic acids. Studies in both humans and animals have shown that CDs can be used to improve drug delivery from almost any type of drug formulation. Currently, there are approximately 30 different pharmaceutical products worldwide containing drug/CD complexes in the market.

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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