Polymers in Drug Delivery

Polymers are being used extensively in drug delivery due to their surface and bulk properties. They are being used in drug formulations and in drug delivery devices. These drug delivery devices may be in the form of implants for controlled drug delivery. Polymers used in colloidal drug carrier systems, consisting of small particles, show great advantage in drug delivery systems because of optimized drug loading and releasing property. Polymeric nano particulate systems are available in wide variety and have established chemistry. Non toxic, biodegradable and biocompatible polymers are available. Some nano particulate polymeric systems possess ability to cross blood brain barrier. They offer protection against chemical degradation. Smart polymers are responsive to atmospheric stimulus like change in temperature;pressure, pH etc. thus are extremely beneficial for targeted drug delivery. Some polymeric systems conjugated with antibodies/specific biomarkers help in detecting molecular targets specifically in cancers. Surface coating with thiolated PEG, Silica-PEG improves water solubility and photo stability. Surface modification of drug carriers e.g. attachment with PEG or dextran to the lipid bilayer increases their blood circulation time. Polymer drug conjugates such as Zoladex, Lupron Depot, On Caspar PEG intron are used in treatment of prostate cancer and lymphoblastic leukemia. Polymeric Drug Delivery systems are being utilized for controlled drug delivery assuring patient compliance.

Solid-state NMR in the field of drug delivery:State of the art and new perspectives

In the last decades,a variety of nuclear magnetic resonance(NMR)techniques have been applied with success in the field of advanced functional materials,including the important area of drug delivery.In such field,solid-state NMR(SSNMR)is an irreplaceable tool in the arsenal of characterization techniques,offering unique and comprehensive perspectives for the description of chemical structure,spatial connectivity and interfacial phenomena of solid dosage forms.This review focuses on the widespread applications of SSNMR in drug delivery field,an overview of selected case studies is provided,together with possible developments.

Protection of the liver against CCl_4-induced injury by intramuscular electrotransfer of a kallistatin-encoding plasmid

AIM:To investigate the effect of transgenic expression of kallistatin(Kal) on carbon tetrachloride(CCl 4)induced liver injury by intramuscular(im) electrotransfer of a Kal-encoding plasmid formulated with poly-Lglutamate(PLG).METHODS:The pKal plasmid encoding Kal gene was formulated with PLG and electrotransferred into mice skeletal muscle before the administration of CCl 4.The expression level of Kal was measured.The serum biomarker levels of alanine aminotransferase(ALT),aspartate aminotransferase(AST),malonyldialdehyde(MDA),and tumor necrosis factor(TNF)-α were monitored.The extent of CCl 4-induced liver injury was analyzed histopathologically.RESULTS:The transgene of Kal was sufficiently expressed after an im injection of plasmid formulated with PLG followed by electroporation.In the Kal gene-transferred mice,protection against CCl 4-induced liver injury was reflected by significantly decreased serum ALT,AST,MDA and TNF-α levels compared to those in control mice(P < 0.01 to 0.05 in a dose-dependent manner).Histological observations also revealed that hepatocyte necrosis,hemorrhage,vacuolar change and hydropic degeneration were apparent in mice after CCl 4 administration.In contrast,the damage was markedly attenuated in the Kal gene-transferred mice.The expression of hepatic fibrogenesis marker transforming growth factor-β1 was also reduced in the pKal transferred mice.CONCLUSION:Intramuscular electrotransfer of plasmid pKal which was formulated with PLG significantly alleviated the CCl 4-induced oxidative stress and inflammatory response,and reduced the liver damage in a mouse model.

Self-assembly of CXCR4 antagonist peptide-docetaxel conjugates for breast tumor multi-organ metastasis inhibition

As a representative chemotherapeutic drug,docetaxel(DTX)has been used for breast cancer treatment for decades.However,the poor solubility of DTX limits its efficacy,and the DTX based therapy increases the metastasis risk due to the upregulation of C-X-C chemokine receptor type 4(CXCR4)expression during the treatment.Herein,we conjugated CXCR4 antagonist peptide(CTCE)with DTX(termed CTCE-DTX)as an anti-metastasis agent to treat breast cancer.CTCE-DTX could selfassemble to nanoparticles,targeting CXCR4-upregulated metastatic tumor cells and enhancing the DTX efficacy.Thus,the CTCE-DTX NPs achieved promising efficacy on inhibiting both bonespecific metastasis and lung metastasis of triple-negative breast cancer.Our work provided a rational strategy on designing peptide-drug conjugates with synergistic anti-tumor efficacy.