Sprayable tissue adhesive microparticle-magnetic nanoparticle composites for local cancer hyperthermia.

Incomplete removal of early-stage gastrointestinal cancers by endoscopic treatments often leads to recurrence induced by residual cancer cells. To completely remove or kill cancer tissues and cells and prevent recurrence, chemotherapy, radiotherapy, and hyperthermia using biomaterials with drugs or nanomaterials are usually administered following endoscopic treatments. However, there are few biomaterials that can be applied using endoscopic devices to locally kill cancer tissues and cells. We previously reported that decyl group-modified Alaska pollock gelatin-based microparticles (denoted C10MPs) can adhere to gastrointestinal tissues under wet conditions through the formation of a colloidal gel driven by hydrophobic interactions. In this study, we combined C10MPs with superparamagnetic iron oxide nanoparticles (SPIONs) to develop a sprayable heat-generating nanomaterial (denoted SP/C10MP) for local hyperthermia of gastrointestinal cancers. The rheological property, tissue adhesion strength, burst strength, and underwater stability of SP/C10MP were improved through decyl group modification and SPION addition. Moreover, SP/C10MP that adhered to gastrointestinal tissues formed a colloidal gel, which locally generated heat in response to an alternating magnetic field. SP/C10MP successfully killed cancer tissues and cells in colon cancer-bearing mouse models in vitro and in vivo. Therefore, SP/C10MP has the potential to locally kill residual cancer tissues and cells after endoscopic treatments.

Impact of reimbursement restriction on drug market sales under the National Health Insurance in Japan.

AIM: National health care expenditures have been increasing each year, although the Japanese government has annually revised official drug prices. Managing the health care system to pay for expensive drugs is a major concern. The reimbursement restriction, which is the only way that a drug can be implemented before market entry in Japan, is crucial for managing expenditures. Therefore, this study identifies the impact of the reimbursement restriction on drug market sales in Japan, particularly in the situation where health technology assessment or other market access regulations are not applicable before market entry. METHOD: All new drugs listed in fiscal years 2011-2019, along with their market size forecast, were identified using the materials from the Central Social Insurance Medical Council. We then calculated the percentage rate of reimbursement amounts based on the National Database of Health Insurance Claims relative to the predicted market size as a dependent variable. Using the reimbursement restriction for each drug as an independent variable, we performed descriptive and univariate analyses on each variable, followed by generalized linear mixed-effects model regression analysis. RESULTS: We identified 211 drugs. The mean rates of drugs that required physicians, facilities, and patients to meet criteria for use were 30.85% (n = 2), 31.42% (n = 2), and 72.11% (n = 6), respectively. The mean rate of drugs that required diagnostic testing was 22.99% (n = 7), which was 3.7 times lower than the rate of drugs that did not require such testing (p < .05). CONCLUSION: Our results indicate that the reimbursement restriction requiring diagnostic testing has a substantial impact on decreasing market sales. As the number of cases for each requirement is small, further study is needed to measure the impact of the other reimbursement restrictions.

Determinants of market prices for drugs under Japan's national health insurance.

AIMS: The Japanese government reimburses patients for drugs at prices specified in the Drug Price Standard (DPS) published by the National Health Insurance (NHI) scheme. It revises reimbursements for most drugs on the basis of their market prices. This study thereby identifies factors related to drugs or disease that impact market prices for drugs using the DPS list. MATERIALS AND METHODS: This study first examined the 2018 DPS list to identify all listed drugs, their prices, and their stipulated reimbursements. We then excluded from this study all the drugs for which prices are set per alternate rules. We calculated the percentage divergence between market prices and DPS prices and designated it our dependent variable. We performed descriptive and a univariate analysis on each variable and constructed multivariate regression models featuring independent variables for drug characteristics that might affect market prices. RESULTS: We identified 1,775 drugs with prices revised only by the market. We observed higher percentage divergences between DPS and market prices for drugs with generic alternatives (p < 0.001), drugs listed in the Japanese Pharmacopoeia (p < 0.001), and drugs for which at least two new drugs entered the same therapeutic category (p < 0.001). Injectable drugs exhibited a more significant and negative correlation with percentage divergences (p = 0.009) than ingestible drugs. Drugs that treat specific organs (p < 0.001), affect metabolism (p = 0.001), and those prescribed for non-therapeutic purposes (p < 0.001) display significantly higher percentage divergence than drugs affecting the nervous system and sensory organs. Divergences are less for narcotics (p < 0.001) and drugs that counter pathologic microorganisms and parasites (p = 0.004). CONCLUSIONS: Factors that elevate competition among pharmaceutical companies likely lower market prices for drugs, and the direction of prices under NHI in Japan is affected by the category of diseases a drug treats.

Hyperthermic effects of dissipative structures of magnetic nanoparticles in large alternating magnetic fields.

Targeted hyperthermia treatment using magnetic nanoparticles is a promising cancer therapy. However, the mechanisms of heat dissipation in the large alternating magnetic field used during such treatment have not been clarified. In this study, we numerically compared the magnetic loss in rotatable nanoparticles in aqueous media with that of non-rotatable nanoparticles anchored to localised structures. In the former, the relaxation loss in superparamagnetic nanoparticles has a secondary maximum because of slow rotation of the magnetic easy axis of each nanoparticle in the large field in addition to the known primary maximum caused by rapid Néel relaxation. Irradiation of rotatable ferromagnetic nanoparticles with a high-frequency axial field generates structures oriented in a longitudinal or planar direction irrespective of the free energy. Consequently, these dissipative structures significantly affect the conditions for maximum hysteresis loss. These findings shed new light on the design of targeted magnetic hyperthermia treatments.