• Archives of Pharmacal Research
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• v.28 no.3
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• pp.364-369
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• 2005

HPMC (Hydroxypropyl methylcellulose) was chemically modified, using maleic anhydrides, to obtain pH-sensitive HPMCAM (Hydroxypropyl methylcellulose acetate maleate) polymers for use as novel duodenum-specific coating agents. The pharmaceutical properties of HPMCAM, such as film forming, acid values, pH-sensitive values, water vapor permeability, tensile strength and Tg, were investigated, and found to show good film forming properties. The pH­sensitive values were 3.0 to 3.7. In vitro results demonstrate that HPMCAM could completely suppress drug release within 2h in a simulated gastric fluid (pH 1.2) and rapidly release the drug in a simulated pathological duodenal fluid (pH 3.4). These results indicate that HPMCAM might be a useful material for a duodenum-specific drug delivery system.

• Archives of Pharmacal Research
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• v.25 no.3
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• pp.229-239
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• 2002

Recent progress in understanding the molecular basis of cancer brought out new materials such as oligonucleotides, genes, peptides and proteins as a source of new anticancer agents. Due to their macromolecular properties, however, new strategies of delivery for them are required to achieve their full therapeutic efficacy in clinical setting. Development of improved dosage forms of currently marketed anticancer drugs can also enhance their therapeutic values. Currently developed delivery systems for anticancer agents include colloidal systems (liposomes, emulsions, nanoparticles and micelles), polymer implants and polymer conjugates. These delivery systems have been able to provide enhanced therapeutic activity and reduced toxicity of anticancer agents mainly by altering their pharmacokinetics and biodistribution. Furthermore, the identification of cell-specific receptor/antigens on cancer cells have brought the development of ligand- or antibody-bearing delivery systems which can be targeted to cancer cells by specific binding to receptors or antigens. They have exhibited specific and selective delivery of anticancer agents to cancer. As a consequence of extensive research, clinical development of anticancer agents utilizing various delivery systems is undergoing worldwide. New technologies and multidisciplinary expertise to develop advanced drug delivery systems, applicable to a wide range of anticancer agents, may eventually lead to an effective cancer therapy in the future.

• Archives of Pharmacal Research
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• v.9 no.2
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• pp.63-73
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• 1986

The use of biodegradable polymetric materials as drug carriers is a relatively new dimension in polymeric drug delivery systems. A number of biodegradable or bioerodible polymers, such as poly(lactic/glycolic acid) copolymer, poly($\alpha$-amino acid), polyanhydride, and poly (ortho ester) are currently being investigated for this purpose. These polymers are useful for matrix and reservoir-type delivery devices. In addition, when chemical functional groups are introduced to the biodegradable polymer backdone, such as poly (N-(2-hydroxypropyl) methacrylamide), the therapeutic agent can be covalently bound directly or via spacer to the backbone polymer. These polymer/drug conjugates represent another new dimension in biodegradable polymeric drug delivery systems. In addition, examples of biodegradable polymeric durg delivery systems currently being investigated will be discussed for the purpose of demonstrarting the potential importance of this new field.

• Archives of Pharmacal Research
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• v.24 no.1
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• pp.1-15
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• 2001

Gene therapy has emerged as a new concept of therapeutic strategies to treat diseases which do not respond to the conventional therapies. The principle of gene therapy is to Introduce genetic materials into patient cells to produce therapeutic proteins in these cells. Gene therapy is now at the stage where a number of clinical trials have been carried out to patients with gene-deficiency disease or cancer. Genetic materials for gene therapy are generally composed of gene expression system and gene delivery system. For the clinical application of gene therapy in a way which conventional drugs are used, researches have been focused on the design of gene delivery system which can offer high transfection efficiency with minimal toxicity. Currently, viral delivery systems generally provide higher transfection efficiency compared with non-viral delivery systems while non-viral delivery systems are less toxic, less immunogenic and manufacturable in large scale compared with viral systems. Recently, novel strategies towards the design of new non-viral delivery system, combination of viral and non-viral delivery systems and targeted delivery system have been extensively studied. The continued effort in this area will lead us to develop gene medicine as "gene as a drug" in the near future.

• Macromolecular Research
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• v.8 no.5
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• pp.199-208
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• 2000

The recent development of biodegradable polymers for drug delivery system (DDS) has been investigated. The biodegradable polymers for DDS are mainly discussed in two categories: one category is natural biodegradable polymers such as polysaccharides, modified celluloses, poly(${\alpha}$-amino acid)s, modified proteins, and microbial biodegradable polymers; the other is synthetic biodegradable polymers such as poly(ester)s, poly(ortho ester)s, poly(phosphazene)s, poly(anhydride)s, poly(alkyl cyanoacrylate)s, and multiblock copolymers. The bioconjugate polymeric drug delivery systems have been also proposed for the design of biocompatible polymeric controlled drug delivery.

• Advances in nano research
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• v.13 no.1
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• pp.87-96
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• 2022

Drug self-delivery systems can easily realize combination drug therapy and avoid carrier-induced toxicity and immunogenicity because they do not need non-therapeutic carrier materials. So, designing appropriate drug self-delivery systems for specific diseases can settle most of the problems existing in traditional drug delivery systems. Retinal pigment epithelium is very important for the homeostasis of retina. However, it is vulnerable to oxidative damage and difficult to repair. Worse still, the antioxidants can hardly reach the retina by non-invasive administration routes due to the ocular barriers. Herein, the targeted group (folic acid) and antioxidant (melatonin) have been grafted on the surface of ZnO quantum dots to fabricate a new kind of drug self-delivery systems as a protectant via eyedrops. In this study, the negative nanoparticles with size ranging in 4~6 nm were successfully synthesized. They could easily and precisely deliver drugs to retinal pigment epithelium via eyedrops. And they realized acid degradation to controlled release of melatonin and zinc in retinal pigment epithelium cells. Consequently, the structure of retinal pigment epithelium cells were stabilized according to the expression of ZO-1 and β-catenin. Moreover, the antioxidant capacity of retinal pigment epithelium were enhanced both in health mice and photic injury mice. Therefore, such new drug self-delivery systems have great potential both in prevention and treatment of oxidative damage induced retinal diseases.

• Journal of Pharmaceutical Investigation
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• v.40 no.spc
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• pp.33-43
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• 2010

Hyaluronic acid (HA) is a biodegradable, biocompatible, non-toxic, non-immunogenic and non-inflammatory linear polysaccharide, which has been used for various medical applications including arthritis treatment, wound healing, ocular surgery, and tissue augmentation. Because of its mucoadhesive property and safety, HA has received much attention as a tool for drug delivery system development. It has been used as a drug delivery carrier in both nonparenteral and parenteral routes. The nonparenteral application includes the ocular and nasal delivery systems. On the other hand, its use in parenteral systems has been considered important as in the case of sustained release formulation of protein drugs through subcutaneous injection. Particles and hydrogels by various methods using HA and HA derivatives as well as by conjugation with other polymer have been the focus of many studies. Furthermore, the affinity of HA to the CD44 receptor which is overexpressed in various tumor cells makes HA an important means of cancer targeted drug delivery. Current trends and development of HA as a tool for drug delivery will be outlined in this review.

• Advances in nano research
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• v.15 no.3
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• pp.225-237
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• 2023

Combination of novel technologies with traditional physiotherapy in rehabilitation in injured athletes have shown to provide improved time of recovery. In specific, nanodrugs delivery systems are widely utilized as a counterpart to the physiotherapy in injuries in sports. In the present study, we focus on the common injuries in dance-sports, their recovery and the effect combination of nano-particle drug delivery with the physiotherapy practices. In this regard, a comprehensive review on the common injuries in dance sport is provided. Moreover, the researches on the effectiveness of the nano-particle drug delivery in therapy of such injuries and in similar cases are provided. The possibility of using combination of nano-particle drug delivery and physiotherapy is discussed in detail. Finally, using artificial intelligence methods, predictions on the recovery time and after-treatment side-effects is investigated. Artificial Neural Network (ANN) predictions suggested that using nano-particle drug delivery systems along with physiotherapy practices could provide shortened treatment time to recovery in comparison to conventional drugs. Moreover, the post-recover effects are less than the conventional methods.

• Journal of Pharmaceutical Investigation
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• v.40 no.spc
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• pp.45-61
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• 2010

Polymeric based nanomedicines have been developed for diagnosing, treating, and preventing diseases in human body. The nanosized drug delivery systems having various structures such as micelles, nanogels, drug-conjugates, and polyplex were investigated for a great goal in pharmaceutics: increasing therapeutic efficacy for diseases and decreasing drug toxicity for normal tissues. The functional polymers used for constituting these drug delivery systems should have several favorable properties such as stimuli-responsibility and biodegrdability for controlled drug release, and solublization capacity for programmed drug encapsulation. This review discusses recent developments and trends of functional polymers (e.g., pH-sensitive polymers, biodegradable polymers, and cationic polymers) used for nanosized drug carriers.

• Journal of Biomedical Engineering Research
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• v.18 no.2
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• pp.173-178
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• 1997

pH sensitive polymers have long been utilized as one important type among many interesting drug delivery systems. This is due to the reason of different pH environments in human organs, which requires different pH control mechanism depending upon the organs. In the present study the pH sensitivity was investigated for both pH sensitive and pH insensitive biopolymers using the diffusion effect along with the swelling effect. NMR microscopy was performed along with optical microscopy. For the analysis of diffusion effect, UMR Microscopy was perFormed to measure diffusion coefficients for various liquids such as distilled water, acetone and DMSO(dimethyl sulfoxide). Also, this technique is expected to contribute to the studies for many pH drug delivery systems.