Table 1.
Summary of matrices used in electrospray for drug delivery.
| Polymer class | Polymer | Degradation mechanism | Degradation rate | Degradation by-products | Ref |
|---|---|---|---|---|---|
| Polyesters | Poly(lactic acid) (PLA) | Hydrolysis of ester bonds | Months | Lactic acid | [37–39] |
| Poly(glycolic acid) (PGA) | Glycolic acid | [37–39] | |||
| Poly(lactic-co-glycolic acid) (PLGA) | Lactic acid and glycolic acid | [37–39] | |||
| Polycaprolactone (PCL) | Caproic acid | [37,40] | |||
| Stimuli responsive | 2-(40-N-dimethylamino-4-nitro-[1,10-biphenyl]-3-yl)butane-l,4-diyl dicarbonyl | Light responsive | Minutes when exposed to visible light (λex = 400–500 nm) | Photocleaved nitro-alkene derivative; secondary products not yet identified | [41] |
| Acetalated Dextran (Ac-DEX; Ace-DEX) | Hydrolysis of acetal groups | Tunable, ranging from hours to months based on reaction time and molecular weight | Dextran and exceedingly low levels of acetone and a short chain alcohol | [3,42–48] | |
| Eudagrits (methacrylic acid and methyl methacrylate co-polymers) | Not biodegradable | – | – | [49] | |
| Natural polymers | Alginate | Not biodegradable | – | – | [50] |
| Cellulose Derivatives | Hydrolysis and cellulases | Varies | Glucose; other degradation products vary by derivatives | [51–53] | |
| Gelatin | Hydrolysis and enzymatic degradation | Weeks or months | Prolylhydroxyproline and glycine | [54–57] | |
| Gliadin | Proteases | Slow: can be resistant to digestion | Glutamine and proline residues | [58,59] | |
| Fibroin | Not biodegradable | – | – | [60] | |
| Maize arabinoxylans | Enzymatic degradation by gut resident microbes | De-branching occurs on the order of days | Arabinose and xylose | [61–64] | |
| Chitosan | Enzymatic degradation | Varies based on degree of deacetylation and molecular weight | Glucosamine and chito-oligosaccharides | [65–67] | |
| Starches from yams | Hydrolysis and enzymatic degradation | Hours | Amylose and Amylopectin | [65,68] | |
| Cationic polymer and lipid | Poyethylenimine (PEI) | Non-biodegradable | – | – | [69–72] |
| 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) | Hydrolysis of ester linkage | Unsaturated diacyl tails and amine head group | [70,73,74] | ||
| Other non-degradable | Ecoflex® | Non-biodegradable | – | – | [75] |
| polymers | Polyethylene glycol (PEG) | – | – | [76–78] | |
| Polyvinyl alcohol (PVA) | – | – | [79,80] |