Rashmi Thakur

Electrospun nanofibrous polymeric scaffold with targeted drug release profiles for potential application as wound dressing.

We have successfully fabricated a dual drug release electrospun scaffold containing an anesthetic, lidocaine, and an antibiotic, mupirocin. Two drugs with different lipophilicities were electrospun from a poly-l-lactic acid (PLLA) solution with a dual spinneret electrospinning apparatus into a single scaffold. The release of the drugs from the scaffold showed different profiles for the two drugs. Lidocaine hydrochloride exhibited an initial burst release (80% release within an hour) followed by a plateau after the first few hours. Mupirocin exhibited only a 5% release in the first hour before experiencing a more sustained release to provide antibacterial action for over 72 h. For comparative purposes, both drugs were spun from a single spinneret and evaluated to determine their release profiles. The scaffold maintained its antibiotic activity throughout the processes of electrospinning and gas sterilization and supported cell viability. It has been reported in the literature that interactions between polymer and drug are known to govern the pattern of drug release from electrospun scaffolds. Here, it was found that the presence of the two drugs in the same polymer matrix altered the release kinetics of at least one drug. Based on the release profiles obtained, the dual spinneret technique was the preferred method of scaffold fabrication over the single spinneret technique to obtain a prototype wound healing device.

Transdermal and buccal delivery of methylxanthines through human tissue in vitro

ABSTRACT We examined the in vitro permeation of central nervous stimulants—caffeine, theophylline, and theobromine across human skin with the aid of six chemical enhancers. It was found that oleic acid was the most potent enhancer for all three methylxanthines. Further optimization studies with different solvents showed that caffeine transport could be enhanced to give flux values up to 585 μg/cm2.hr−1. Theobromine and theophylline delivery rates proved insufficient. An additional study involving a buccal tissue equivalent showed that this membrane was more permeable than skin for all model actives tested and would offer an alternate way of delivery.

Structural and Biochemical Changes in Aging Skin and Their Impact on Skin Permeability Barrier

Publisher Summary Skin transformations are the most perceptible signs of aging. The multifaceted functions of the skin include acting as an entry barrier to compounds, regulating body temperature and fluid and electrolyte balance, and providing receptors for sensations such as touch, pain, and pressure. This chapter presents a synopsis of systematic and detailed studies on this topic. As skin ages, it undergoes certain morphological and functional changes, which lead to altered drug permeability, increased susceptibility to irritant contact dermatitis, and in addition possibly severe xerosis. From the published literature, it seems that the thickness of the stratum corneum does not change significantly with age, but there is an increase in the surface area of the corneocytes. Other major changes include reduced elasticity of the epidermis, a decrease in the number of sweat glands and an increased loss of collagen and elastin. There are a number of smaller variations occurring structurally and biochemically with age such as the reduction in skin lipids and a reduction in cell turnover. The complex nature and high number of changes occurring simultaneously as well as the experimentally introduced variations due to the use of subjects of different races, genders, ethnicity, and ages make it difficult to draw conclusive correlations between such changes and alterations in permeation of drugs through aged skin.