Self-delivery System Research Articles

ChemInform Abstract: Hyperbranched Polyphosphates: Synthesis, Functionalization and Biomedical Applications

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A supramolecular hydrogel based on carbamazepine.

In this communication we report the first supramolecular hydrogel based on an antiepileptic drug carbamazepine (CBZ). CBZ plays the dual role of a drug molecule and an aromatic capping group in this self-delivery system.

Self-delivery nanoparticles from an amphiphilic covalent drug couple of irinotecan and bendamustine for cancer combination chemotherapy

We demonstrate an approach to prepare an anticancer drug self-delivery system from an amphiphilic covalent drug couple (Ir–Bd) for cancer combination chemotherapy.

Combination of small molecule prodrug and nanodrug delivery: amphiphilic drug-drug conjugate for cancer therapy.

All drugs for cancer therapy face several transportation barriers on their tortuous journey to the action sites. To overcome these barriers, an effective drug delivery system for cancer therapy is imperative. Here, we develop a drug self-delivery system for cancer therapy, in which anticancer drugs can be delivered by themselves without any carriers. To demonstrate this unique approach, an amphiphilic drug-drug conjugate (ADDC) has been synthesized from the hydrophilic anticancer drug irinotecan (Ir) and the hydrophobic anticancer drug chlorambucil (Cb) via a hydrolyzable ester linkage. The amphiphilic Ir-Cb conjugate self-assembles into nanoparticles in water and exhibits longer blood retention half-life compared with the free drugs, which facilitates the accumulation of drugs in tumor tissues and promotes their cellular uptake. A benefit of the nanoscale characteristics of the Ir-Cb ADDC nanoparticles is that the multidrug resistance (MDR) of tumor cells can be overcome efficiently. After cellular internalization, the ester bond between hydrophilic and hydrophobic drugs undergoes hydrolysis to release free Ir and Cb, resulting in an excellent anticancer activity in vitro and in vivo.

Disulfide bond reduction-triggered molecular hydrogels of folic acid–Taxol conjugates

Molecular hydrogels of therapeutic agents are a novel kind of self-delivery system that can sustain release of drugs or pro-drugs. We have previously developed a molecular hydrogelator of folic acid (FA)-Taxol conjugate triggered by phosphatase. In this paper, we report a novel molecular hydrogelator system of FA-Taxol conjugates with improved synthetic strategy. The hydrogels are formed by the reduction of disulfide bond by glutathione (GSH). These hydrogels could sustain release of Taxol through ester bond hydrolysis. Compared with intravenous (i.v.) injection of clinically used Taxol® with four times the dosage, our hydrogel could inhibit tumor growth more efficiently by a single dose of intra-tumor (i.t.) administration. These observations suggested the big potential of this novel gelation system of Taxol for cancer therapy.

Molecular hydrogels of hydrophobic compounds: a novel self-delivery system for anti-cancer drugs

Cancer chemotherapy is usually necessary and to date remains the best way to reduce the size of solid tumors, eliminate tumor residues and prevent tumor metastasis after surgery. However, anti-cancer drugs such as Taxol and cisplatinum-based drugs frequently suffer from low water solubility and result in adverse side effects. An injectable delivery system that can sustainedly release anti-cancer drugs may improve the efficiency of chemotherapy and prolong the life of patients. We highlight in this paper on a novel self-delivery system of molecular hydrogels based on anti-cancer drugs. This novel kind of self-delivery system with a high weight percentage of anti-cancer drugs is injectable and can release anti-cancer drugs sustainedly over a long period of time. It might be administrated to the inside of tumors to reduce the their size for patients in a late stage of cancer or administrated in the cavities left by tumor removal to eliminate tumor residues and prevent metastasis.

Aerosol vaccination of the brushtail possum ( Trichosurus vulpecula) with bacille Calmette–Guérin: the duration of protection

Bovine tuberculosis is endemic in wild brushtail possums ( Trichosurus vulpecula) in New Zealand. The disease is controlled by reducing or eliminating infected possum populations, but control methods do not kill all possums in the targeted area, leaving some tuberculous possums to maintain the disease. Vaccination with bacille Calmette–Guérin (BCG) has been shown to provide significant levels of protection. Vaccination is a potential alternative or complementary control strategy if protection is long lasting. Captive possums were vaccinated with a single dose of BCG by intranasal aerosol and challenged by intratracheal instillation of Mycobacterium bovis 2, 6 or 12 months after vaccination. Vaccination produced significant immunity as measured by the lymphocyte proliferative response to bovine PPD and protection in response to challenge. The protective response was seen as a decrease in the mass of pulmonary lesions and decreased dissemination to the abdominal organs and body lymph nodes. The protective effect was strongest at 2 months after vaccination but was still present at a lower level at 12 months. Delivery of an aerosol vaccine to possums in the wild using a self-delivery system could contribute substantially to wildlife tuberculosis control.

Eucalyptus: a sustainable self-delivery molluscicide?

Attention is drawn to the limitations of conventional methods of controlling important trematode infections such as schistosomosis and fasciolosis. Plant molluscicides could have a role in the future control of these infections. There are, however, major problems with most plant molluscicides in that their use is labour-intensive, in many cases relatively skilled workers are required, they must be applied regularly and arable land may be required for their cultivation. Thus, little progress is to be expected until plant species with sustainable self-delivery systems are identified. Eucalyptus is proposed as a likely candidate. The leaves of many species in this genus have molluscicidal properties and their intermittent fall could effect self-delivery if the trees were planted in appropriate places. Relatively little work has been carried out on this possibility and much more is necessary, especially field trials. Before field trials are started, more laboratory testing is also necessary to determine the LC50 values for different snail species and to study toxicity to non-target organisms.