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The effect of pH, water hardness and temperature in water on release profile of time-controlled release granule (TCRG) was investigated. The release profile of metominostrobin from TCRG did not change regardless of changing pH from 4 to 10 and water hardness from 3 to 100. However, as the temperature increased, the lag time was shortened and the release rate became faster. When the logarithmic cumulative temperature was plotted as abscissa and release percentage as ordinate, the release profiles measured at fixed temperatures (15. 20, 25, 30°C) and changing temperatures from 15 to 30°C periodically were superposed. Therefore, the released percentage could be predicted from cumulative temperature. Thus, it was thought that the difference in water permeation through PVC membrane by temperature caused different release profiles.

A novel controlled drug release system on agrochemicals, time-controlled release granule (TCRG). which is characterized as an active ingredient release with a lag time, has been developed. This TCRG has a five-layered structure composed of core, active ingredient, swelling agent and two water-insoluble polymer membranes. The release profile of TCRG showed that lag time and release rate were optionally controlled by the coated amount of a water-insoluble polymer membrane, polyvinylidene chloride (PVC) and/or by the amount of a swelling agent, acrylate starch.

We investigated the effect of white carbon (hydrated silicon dioxide) contained in water insoluble polymer membrane on release profiles of metominostrobin from the time-controlled release granule (TCRG) containing metominostrobin. As the amount of white carbon increased, the lag time for release was shortened and the release rate became faster. Thus, the changes in both lag time and release rate were thought to be related to water permeability into the TCRG and tensile strength of the membrane induced by it. We also made a single regression model and a logistic model to predict release profile based on the amount of white carbon in TCRG using computer program NLIN procedure of SAS (Statistical Analysis Systems). As a result, the actual release profile fitted in a three parameter logistic model by non linear least-squares method.

We examined the effect of talc as an vehicle on release profile of time-controlled release grantic (TCRG). In this report, TCRG was prepared by coating a water insoluble polymer to the pre-coated granule which consists of a powder blend containing active ingredient, swelling agent and talc. The lag time of metominostrobin release from TCRG was prolonged with increase of talc, a hydrophobic vehicle, We discussed the mechanism in this phenomenon.

モデル薬物としてメトミノストロビンを用い, 粒剤表面を疎水性高分子で被覆した徐放性粒剤からの溶出挙動におよぼす被覆方法 (高分子液の滴下または流動層造粒機による被覆) と被覆液中の高分子濃度 (5および50%) の影響を調べた. その結果, 1) 高分子濃度50%の被覆液を用いて滴下または流動層造粒機で被覆した場合, 薬物の放出速度は滴下による被覆法>流動層造粒機による被覆法であったが, 溶出機構は同一であった. 2) 流動層造粒機による被覆の場合, 薬物の放出速度は高分子濃度5%

カラスムギ (Avena fatua L.) はコムギ畑における強害雑草の一つであり, それを茎葉処理で防除できるものの一つとして, ジクロホップメチルが現在広く使用されている. しかし, そのジクロホップメチルは他のアリールオキシフェノキシプロピオン酸系除草剤に比べて低活性である. 今回, 著者らが新規に合成した2-[4-(3,5-ジクロロ-2-ピリジニロキシ)フェノキシ]プロピオンアミドキシ酢酸誘導体のなかにコムギ・カラスムギ問で選択性を示す化合物を数種見いだした. それらのなかで, N-エチル-2-[4-(3,5-ジクロロ-2-ピリジルオキシ)フェノキシ] プロピオンアミドキシアセトアミド (23) はジクロホップメチルと比べて, カラスムギに対する除草活性は2～4倍強く, しかもコムギ・カラスムギ間でそれと同程度の選択幅を示した.

The adsorption of SSF-126, (E)-2-methoxyimino-N-methyl-2-(2-phenoxyphenyl)acetamide, on the mineral clay was exothermic. However, that on the activated carbon was endothermic, which is different from the general characteristics of physical adsorption. The release of SSF-126 from the granules highly depended on the adsorption and desorption properties of the adsorbents for SSF-126. It was possible to control the release rates of SSF-126 from the granules intentionally to a considerable degree by changing the compounding amount and quality of the activated carbon. Moreover, it is suggested that the release can be further inhibited, and also different release patterns can be obtained when combined with ethylcellulose having a controlled release function.

異なった溶出挙動を有する時間制御型溶出性粒剤 (TCRG) を育苗箱施用し, 薬害が生じず長期にわたって防除効果を維持する最適なTCRG処方の選択をおこなった. メトミノストロビンのイネ体中濃度が急激に上昇し始める時期は, TCRGのラグタイムとほぼ一致した. また, TCRGを処理した場合, 薬害は生じなかった. しかしながら, ラグタイムが2週間程度, 溶出速度が約3%/日のTCRG (TC-1) を処理したイネ体中濃度は, ラグタイムが3週間程度, 溶出速度が約1.7%/日のTCRG (TC-2) に比して高濃度であり, この濃度に応じていもち病防除効果は長期にわたって持続した. 以上の結果から, TC-1を育苗箱施用した場合, 薬害が生じず, 長期にわたっていもち病防除効果を持続することが明らかとなった.

メトミノストロビン (E)-2-methoxyimino-N-methyl-2-(2-phenoxy-phenyl)acetamide の溶出速度がほぼ一定である放出制御粒剤を, 酢酸ビニル-アクリル共重合体を粒剤の表面に被覆することにより, 調製した. 本剤を育苗箱に施用した時のメトミノストロビンの稲体中濃度およびいもち病防除効果を非放出制御粒剤のそれらと比較した. その結果, 放出制御粒剤はメトミノストロビンの稲体中濃度を長期にわたって維持することができ, イネいもち病の防除効果の持続性にも優れていることが認められた.

SSF-126, (E)-2-methoxyimino-N-methyl-2-(2-phenoxyphenyl)-acetamide の放出制御粒剤は, 一般的な崩壊型粒剤に比ベポット田面水中の濃度推移が増加, 減少とも滑らかであり, 処理5日目以降高い濃度を示した. さらに防除効果においてもこの傾向はそのまま反映され, 処理10日目以降の残効性は放出制御粒剤が優れていた. SSF-126の粒剤からの放出制御により, 同じ有効成分投下量でもより長期にわたって安定なイネいもち病の防除が可能になることが示唆された.