How many types of transdermal drug delivery systems are there?
Today, there are 19 transdermal delivery systems for such drugs as estradiol, fentanyl, lidocaine and testosterone; combination patches containing more than one drug for contraception and hormone replacement; and iontophoretic and ultrasonic delivery systems for analgesia (Table 1, Fig. 1).
What are transdermal drug delivery systems?
TDD is a painless method of delivering drugs systemically by applying a drug formulation onto intact and healthy skin [2,5]. The drug initially penetrates through the stratum corneum and then passes through the deeper epidermis and dermis without drug accumulation in the dermal layer.
What is the difference between reservoir and matrix systems?
In the reservoir patch, the membrane limits the rate of drug delivery; in the matrix system, it is the formulation of the drug/polymer matrix. Reservoir patches give tighter control of delivery rates but can have an initial burst of drug release.
What are the advantages of transdermal drug delivery systems?
Potential advantages of transdermal delivery include, but are not limited to, elimination of first-pass metabolism, steady delivery/blood levels, better patient compliance, reduced systemic drug interactions, possible dose intervention, avoidance of medically assisted drug administration, prolonged drug administration.
What are the different factors affecting transdermal drug delivery system?
Biological factors, such as gender, age, ethnicity, disease, skin hydration, and application site, all of which may cause variability in drug absorption across the skin, are discussed as are the transdermal delivery systems, which may be employed to overcome these variations.
What is matrix and reservoir system?
In reservoir-based systems, the drug reservoir is enclosed within polymer coatings. The drug releases through the rate-controlling porous polymeric membrane. Monolithic matrix systems are similar to reservoir-based systems, but in this case, the drug is dispersed or dissolved within a rate-controlling polymer matrix.
What is matrix and reservoir?
In a matrix or monolithic delivery system the drug is either molecular dissolved or dispersed inside a matrix. Compared to a reservoir system, a matrix system is not enveloped within a rate limiting membrane. As such the release rate of the drug from the matrix system is normally not constant and decreases in time.
What is matrix type transdermal patch?
The matrix type transdermal patches containing LRDP were prepared using different ratios of ERL and HPMC (Table 1). The polymers were weighed in requisite ratios by keeping the total polymer weight at 1.0 gm and allowed to swell for 2 hrs in solvent mixture (3:2 ratio of dichloromethane, methanol).
What are the characteristics of drug delivery system?
Ideal characteristics of drug delivery systems It should increase the bioavailability of the drug. It should transport the drug intact to the site of action while avoiding the non-diseased host tissue. The product should be stable and delivery should be maintained under various physiological variables.
What are the disadvantages of transdermal drug delivery system?
Disadvantages of transdermal route of drug administration The drug, the adhesive, or excipients in the patch formulation may cause rashes, local irritation, erythema, or contact dermatitis.