other materials, viz. elastomers and adhesives (Boateng et al. 2008). They allow

water vapour to pass through but restrict the bacteria. These dressings are used for

mild to moderate wounds like pressure sore and minor burn, and they are also

recommended for paediatric wound management (Thomas 1992). They produce

gels on contact with wound exudate and maintain the moist condition. The

hydrocolloids are not very effective for neuropathic ulcers or high exuding wounds.

The electrospun patches are highly permeable in nature and have the ability to

deliver any kind of drugs to the wound site at a faster rate (Kataria et al. 2014).

Further, this porous structure allows passing air or exudates easily and helps to

maintain the moisture label in the wound site. Further, they have large surface area,

are easy to process and are benign to the wounds. Poly(lactic acid) (PLA) and poly

(ε-caprolactone) (PCL) are highly biocompatible in nature, and their electrospun

scaffolds are very effective in delivering different biologically active molecules at

the wound site. The wound dressing with thymol-loaded PLA-PCL composite

nanofibres show better wound contraction as compared to thymol-loaded pure

PCL/PLA nanofibres (Karami et al. 2013). The bioactive dressings are usually

produced from natural tissue or artificial sources like collagen (Ramshaw et al.

1996), hyaluronic acid (Doillon and Silver 1986), chitosan (Ishihara et al. 2002),

alginate and elastin. Sometimes, these dressing materials are incorporated with

antimicrobials or growth factors to promote wound healing process depending on

the nature of the wound. Collagen, one of the important structural proteins, has

important role in fibroblast formation and endothelial migration in wound healing,

while hyaluronic acid being a glycosaminoglycan component of extra cellular matrix

(ECM) has unique biological or physiological features. Both of them are biocom-

patible and biodegradable and lack immunogenicity in nature (Supp and Boyce

2005). As compared to other dressings, biological dressings are reported to be

superior to other types of dressings.

30.4

Characterization of Dressing Materials

Characterization of any dressing material is necessary before its application on

animals and human beings. The necessary characterizations like drug loading effi-

ciency of the dressing material, physical state of the dressing after drug loading, size

of the drug in the dressing material, in vitro release kinetics of the drug from dressing

material and the effect of drug-loaded scaffold on secondary or primary cells are very

essential for their further applications. The polysaccharide (PAP) residue of

Periplaneta americana has a long medicinal history which is being used in wound

management. The composite hydrogel made of PAP, carbomer 940 (CBM) and

carboxymethyl cellulose (CMC) shows better three-dimensional network structure,

improves swelling and water retention capability and bears decent mechanical

strength as compared to pure polymer hydrogels (Fig. 30.1a(i), (ii)) (Wang et al.

2020). The cytocompatibility of the hydrogels is examined with 3T3 fibroblast cell

line revealing composite hydrogels are biocompatible in nature. In another study,

curcumin-phospholipid complex (CPC) is incorporated into a thermosensitive

30

Polymeric Vehicles for Controlled Delivery of Ayurvedic Drugs for Wound. . .

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