PLGA nanosphere was firstly prepared by polymeric spherical crystal crystallization method (1993), which has been developed by modifying the spherical crystallization process (1982) with polymer introduced. Biodegradable properties of PLGA nanospheres are described in terms of biological half life and degradation mechanism. The preparation method of PLGA nanosphere by polymeric spherical crystallization process, SA and ESD method, is described as well as phase separation, emulsion solvent evaporation, salting out and other methods. PLGA nanosphere was developed to locally administerd DDS, such as colon targeted DDS of tacrolimus and intra articular DDS of bethamethasone sodium phosphate. PLGA nanosphere has been further developed for peptide delivery via mucous membrane, eg oral and pulmonary administration of calcitonin and insulin. It was found that the surface modification of PLGA nanosphere with mucoadhesive polymer, i.e., chitosan improved significantly the pharmacological effect and prolonged the action. Nanocomposite system of PLGA nanosphere modified with chitosan for pulmonary delivery of insulin and calcitonin has been newly developed under NEDO's project. Dry powder inhalation (DPI) DDS of peptide with nanocomposite system has been successfully developed as a non-invasive delivery system. Further new trial for gene delivery and for preparation of nanomedical device are extensively carried out. Fucntional cosmetics with vitamin C loaded PLGA nanosphere were launched recently.
In order to reduce pain associated with insulin injection, a tapered tip 32G 6 mm needle has been developed. The aim of this study was to evaluate this tapered needle in comparison with an ordinary straight 31G needle-namely Pen Needle 32G Taper (PN 32G Taper) and Pen Needle 31G 6 mm (PN 31G 6 mm)-in terms of patients' preference, pain perception and usability. Thirty five diabetic patients who used only PN 31G 6 mm (mean age 62.9, male/female: 18/17) were included in this study to answer questionnaires before and after using PN 32G Taper. There were no significant differences between body mass index, HbA1c, daily dosage of insulin injection (IU/day), and maximum dosage of one insulin injection (IU/times) between before and after using PN 32G Taper. With PN 32G Taper, we found statistically significant decrease in frequency of pain (p<0.001), degree of pain (p<0.001), hemorrhage (p<0.001), internal hemorrhage (p<0.05), and dosing force (p<0.001), but significant increase of satisfaction (p<0.001) and recommendation of PN 32G Taper for other patients (p<0.001) compared to PN 31G 6 mm. Using PN 32G Taper for insulin injection will contribute to enhance adherence for diabetes self-management.