Bio-compatible polyurethane microcapsules and process for the preparation thereof

Patent metadata

Field	Value
Publication number	US-12233167-B2
Application number	US-202017601583-A
Country	US
Kind code	B2
Filing date	Mar 27, 2020
Priority date	Apr 5, 2019
Publication date	Feb 25, 2025
Grant date	Feb 25, 2025

Abstract

The present invention relates to partially bio-based and bio-compatible polyurethane microcapsules. More particularly, the present invention relates to partially bio-based and bio-compatible polyurethane microcapsules for sustained release of an active ingredient. The present invention also relates to a process for the preparation of the partially bio-based and bio-compatible polyurethane microcapsules.

First claim

We claim:

1. A partially bio-based polyurethane microcapsule for sustained release of an active ingredient comprising;
i) a core containing at least one active ingredient selected from the group consisting of dimethyl phthalate, N,N-Diethyl-meta-toluamide (DEET), Ibuprofen, Diuron, Zinc Pyrithione, Irgarol, and 4-Anisaldehyde; and
ii) a bio-compatible polymeric shell consisting of (a) a bio-based aliphatic diol, (b) an aliphatic diisocyanate, (c) a cross linker and (d) an additive; wherein the bio-based aliphatic diol is selected from the group consisting of isosorbide, 1,3-propane diol, 1,4-butane diol, 2,3-butane diol, and 1,6-hexane diol and the aliphatic diisocyanate is selected from the group consisting of 1,6 Hexamethylene diisocyanates (HMDI), Isophorone diisocyanate (IPDI), pentamethylene diisocyanates (PDI), and 4,4′-Diisocyanatodicyclohexylmethane (H 12 MDI); wherein said additive is selected from the group consisting of nanocellulose, nanoclay, nanosilica and carbon nanotube (CNT);

wherein, the mole ratio of diisocyanate to hydroxyl groups present in aliphatic diol is 1.2:1;
and wherein, the partially bio-based polyurethane microcapsule has an encapsulation efficiency of 70-95%.

2. The partially bio-based polyurethane microcapsule as claimed in claim 1 , wherein said cross linker is selected from the group consisting of glycerol, trimethylol propane (TMP), triethylenetetramine (TETA) and trimethylol ethane (TME).

3. A process for the synthesis of a partially bio-based polyurethane microcapsule, as claimed in claim 1 , using interfacial polycondensation comprising the steps of
a) preparing a solution of additive in water by overnight stirring followed by homogenization to obtain a dispersion;
b) adding the dispersion prepared in step (a) to a solution of a surfactant in water followed by sonicating to obtain a continuous phase;
c) emulsifying a solution of aliphatic diisocyanate and an active ingredient in the continuous phase obtained in step (b) to obtain a first mixture;
d) preparing a second mixture of a bio-based aliphatic diol, a cross-linker and a catalyst in water;
e) adding the second mixture obtained in step (d) drop-wise to the first mixture obtained in step (c) to obtain a reaction mixture; and
f) stirring the reaction mixture followed by centrifugation and filtration to obtain the partially bio-based and bio-compatible polyurethane microcapsules.

4. The process as claimed in claim 3 , wherein said surfactant is selected from the group consisting of polyvinyl pyrrolidone (PVP K-90), polyvinyl pyrrolidone (PVP K-30), polyvinyl alcohol (PVA), Tween 80, sodium lignosulphonate (SLS) and sodium dodecyl sulfate (SDS).

5. The process as claimed in claim 3 , wherein said catalyst is selected from the group consisting of 1,4-Diazabicyclo[2.2.2]octane (DABCO), and DibutyltinDilaurate (DBTDL).

6. The process as claimed in claim 3 , wherein said additive is selected from the group consisting of nanocellulose, nanoclay, nanosilica and carbon nanotube (CNT).

7. The process as claimed in claim 3 , wherein said bio-based aliphatic diol is selected from the group consisting of isosorbide, 1,3-propane diol, 1,4-butane diol, 2,3-butane diol, and 1,6-hexane diol.

8. The process as claimed in claim 3 , wherein said aliphatic diisocyanate is selected from the group consisting of 1,6 (HMDI), Isophorone diisocyanate (IPDI), pentamethylene diisocyanates (PDI), and 4,4′-Diisocyanatodicyclohexylmethane (H 12 MDI).

9. The process as claimed in claim 3 , wherein said cross linker is selected from the group consisting of glycerol, trimethylol propane (TMP), triethylenetetramine (TETA) and trimethylol ethane (TME).

10. The process as claimed in claim 3 , wherein the active ingredient is selected from the group consisting of dimethyl phthalate, N,N-Diethyl-meta-toluamide (DEET), Ibuprofen, Diuron, Zinc Pyrithione, Irgarol, and 4-Anisaldehyde.

Assignees

• Council Scient Ind Res

Inventors

• Sadavarte Nilakshi Vaibhav
• Shanmuganathan Kadhiravan
• Shukla Parshuram Gajanan

Classifications

• A61K31/192

  having aromatic groups, e.g. sulindac, 2-aryl-propionic acids, ethacrynic acid  {(cannabinoids A61K31/658)} · CPC title

• B01J13/16

  Interfacial polymerisation · CPC title

• A61K31/555

  containing heavy metals, e.g. hemin, hematin, melarsoprol · CPC title

• A61K31/11

  Aldehydes · CPC title

• A61K9/5089

  Processes · CPC title