generally applicable for non-exudating to slightly exudating wounds. Further,

Bactigras, Jelonet and Paratulle are examples of commercially available tulle dress-

ing which are appropriate for superficial clean wounds. The limitations of the

traditional dressings, like frequent changing of dressing, fail to maintain moist

condition which produces appropriate situation for modern dressing to come up

with more advanced formulations (Boateng et al. 2008). The modern dressings are

designed to provide proper moist condition, air circulation and active components to

the wound to promote the cell migration and angiogenesis for faster healing. There

are numerous dressing materials available in the market depending on the cause and

type of the wounds. The modern dressings can be classified as passive, interactive

and bioactive, and usually the synthetic or natural polymers are used for this

purpose. The interactive dressings are basically polymeric films, hydrogels and

hydrocolloids which function as a blockade against dispersion of bacteria to the

wound environment (Rivera and Spencer 2007; Strecker-McGraw et al. 2007). The

passive dressings are non-occlusive like gauze and are applied to cover up the wound

to promote the healing underneath.

30.3

Polymeric Drug Delivery Vehicle

Polymeric drug delivery vehicles allow the delivery of any therapeutically active

molecules inside human body in a controlled and sustained manner. Further, it

provides better protection and improves effectiveness of the drug by tuning the

rate, time and site of release in the human body. Polymeric drug delivery vehicles

can be nanoparticles, hydrogels, films and scaffolds in nature. Different stages of

wound require different forms of dressing materials. Hence, proper selection of a

delivery vehicle is a tricky job (Biswas et al. 2018b). Recently, researchers are

looking for new alternative to modern medicines like antibiotics, corticosteroids, etc.

for wound healing to eliminate the side effects of these medicines. Ayurvedic

medicine incorporated in polymeric delivery vehicles can be a good alternative.

Hydrogels are three-dimensional polymeric networks that can hold different

drugs inside network structure and release the drug in controlled manner. Hydrogels

are generally used to treat dry chronic wounds, necrotic wounds, pressure ulcers and

burn wounds. The starch-zeolite nanocomposite hydrogel by incorporating herbal

drug chamomile is able to control the release of the drug along with greater

absorption of the exudates which results in better contraction of the wound as

compared to pure hydrogel. Further, the effectiveness of simvastatin in wound

healing significantly improved after incorporating simvastatin-chitosan nanoparticle

in poly(vinyl alcohol) hydrogel as compared to simvastatin ointment (Yasasvini

et al. 2017). The hydrogel dressings have some limitations like low mechanical

strength and exudate accumulation which make them difficult to handle and leads to

maceration and bacterial proliferation (Martin et al. 2002). Hydrocolloids are made

of two layers, inner colloidal layer and outer water-impermeable layer. It is one of

the highly used interactive wound dressings. Hydrocolloid dressings are the combi-

nation of gel-forming agents like carboxymethyl cellulose, gelatin and pectin and

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A. Biswas et al.