Preparation method of imidacloprid composite drug-loaded microspheres

[0038] Example 1:

[0039] The preparation of imidacloprid composite drug-loaded microspheres (CMC@CS / MWCNT) includes the following steps:

[0040] (1) Preparation of acid chloride-modified MWCNTs

[0041] Disperse 150 mg of MWCNT-COOH in 30 mL of thionyl chloride (SOCl 2 ), refluxed under vigorous stirring at 30 °C for 24 h, the residue was separated by filtration, washed three times with 100 mL of N’N-dimethylamide, and dried under vacuum at 80 °C to synthesize acid chloride-modified MWCNT (MWCNT-COCl).

[0042] (2) Preparation of chitosan-modified MWCNT polymer (CS / MWCNT)

[0043] 2.5 g of chitosan was suspended in 100 mL of DMF and allowed to swell for 24 h, then 1.0 g of MWCNT-COCl was added. The grafting reaction was carried out at 90°C for 24h. It was washed 3 times with 1% acetic acid solution (to remove free chitosan), and the CS / MWCNT grafted polymer was vacuum dried to constant weight at 65°C.

[0044] (3) Preparation of imidacloprid composite drug-loaded mi

[0046] Example 2:

[0047] The preparation of imidacloprid composite drug-loaded microspheres (CMC@CS / MWCNT) includes the following steps:

[0048] (1) Preparation of acid chloride-modified MWCNTs

[0049] Disperse 200 mg of MWCNT-COOH in 50 mL of thionyl chloride (SOCl 2 ), refluxed under vigorous stirring at 30 °C for 26 h, the residue was separated by filtration, washed 5 times with 100 mL of N’N-dimethylamide, and dried under vacuum at 60 °C to synthesize acid chloride-modified MWCNT (MWCNT-COCl).

[0050] (2) Preparation of chitosan-modified MWCNT polymer (CS / MWCNT)

[0051] 2 g of chitosan was suspended in 80 mL of DMF and allowed to swell for 24 h, then 1.8 g of MWCNT-COCl was added. The grafting reaction was carried out at 90°C for 24h. It was washed 3 times with 2% acetic acid solution (to remove free chitosan), and the CS / MWCNT grafted polymer was vacuum dried to constant weight at 60°C.

[0052] (3) Preparation of imidacloprid composite drug-loaded microsphe

[0054] Example 3:

[0055] The preparation of imidacloprid composite drug-loaded microspheres (CMC@CS / MWCNT) includes the following steps:

[0056] (1) Preparation of acid chloride-modified MWCNTs

[0057] Disperse 100 mg of MWCNT-COOH in 20 mL of thionyl chloride (SOCl 2 ), refluxed under vigorous stirring at 30 °C for 24 h, the residue was separated by filtration, washed three times with 80 mL of N’N-dimethylamide, and dried under vacuum at 80 °C to synthesize acid chloride-modified MWCNT (MWCNT-COCl).

[0058] (2) Preparation of chitosan-modified MWCNT polymer (CS / MWCNT)

[0059] 2.3 g of chitosan was suspended in 80 mL of DMF and allowed to swell for 24 h, then 0.9 g of MWCNT-COCl was added. The grafting reaction was carried out at 90°C for 24h. It was washed 3 times with 1% acetic acid solution (to remove free chitosan), and the CS / MWCNT grafted polymer was vacuum dried to constant weight at 65°C.

[0060] (3) Preparation of imidacloprid composite drug-loaded micr