Challenges and Opportunities in dermal/transdermal Delivery

Abstract

Transdermal drug delivery is an exciting and challenging area. There are numerous transdermal delivery systems currently available on the market. However, the transdermal market still remains limited to a narrow range of drugs. Further advances in transdermal delivery depend on the ability to overcome the challenges faced regarding the permeation and skin irritation of the drug molecules. Emergence of novel techniques for skin permeation enhancement and development of methods to lessen skin irritation would widen the transdermal market for hydrophilic compounds, macromolecules and conventional drugs for new therapeutic indications. As evident from the ongoing clinical trials of a wide variety of drugs for various clinical conditions, there is a great future for transdermal delivery of drugs.Delivery of drugs through the skin has been an attractive as well as a challenging area for research. Advances in modern technologies are resulting in a larger number of drugs being delivered transdermally including conventional hydrophobic small molecule drugs, hydrophilic drugs and macromolecules. Transdermal systems are a desirable form of drug delivery because of the obvious advantages over other routes of delivery. Transdermal delivery provides convenient and pain-free self-administration for patients. It eliminates frequent dosing administration and plasma level peaks and valleys associated with oral dosing and injections to maintain a constant drug concentration, and a drug with a short halflife can be delivered easily. All this leads to enhanced patient compliance, especially when long-term treatment is required, as in chronic pain treatment and smoking cessation therapy. Avoidance of hepatic first-pass metabolism and the GI tract for poorly bioavailable drugs is another advantage of transdermal delivery. Elimination of this first-pass effect allows the amount of drug administered to be lower, and hence safer in hepato-compromised patients, resulting in the reduction of adverse effects. Transdermal systems are generally inexpensive when compared with other therapies on a monthly cost basis, as patches are designed to deliver drugs from 1 to 7 days. The other advantage of transdermal delivery is that multiple dosing, on-demand or variable-rate delivery of drugs, is possible with the latest programmable systems, adding more benefits to the conventional patch dosage forms. The general acceptability of transdermal products by patients is very high, which is also evident from the increasing market for transdermal products. The transdermal drug delivery market, worth $12.7 billion dollars in 2005, is expected to reach $32 billion in 2015 [1].

Transdermal Protein Delivery Using Choline and Geranate (CAGE) Deep Eutectic Solvent

“…[63,64] However, it is to be noted that chemical enhancers have more successfully been used mostly for small molecule delivery, as they do not provide similar degrees of penetration enhancement as physical enhancement methods. [65] This notion was corroborated in our study where no improvement in penetration of FITC-BSA, FITC-OVA, or FITC-insulin across the skin was observed in the presence of CPEs such as ethanol or DGME, while a significant enhancement in delivery of these proteins was noted in the presence of CAGE. Further quantitation of 3 H-BSA penetration into different layers of the skin after 24 h treatment with different materials also demonstrated significantly higher accumulation of BSA in the dermis and acceptor chamber when the protein was delivered using CAGE compared to PBS or aforementioned CPEs.…”

Microneedle characterisation: the need for universal acceptance criteria and GMP specifications when moving towards commercialisation

“…Furthermore, the convenience and non-invasive nature of TDD offers improved patient acceptability and compliance. The TDD market, worth $12.7 billion dollars in 2005, is expected to reach $32 billion in 2015 and as such, has been an important area of pharmaceutical research and development for the last few decades [1,2,3,4].…”

Transdermal Drug Delivery and Methods to Enhance It

“…Суть химического способа улучшения проник-новения ЛВ через кожу заключается либо в моди-фицировании молекул ЛВ, либо во введении в ТТС активаторов переноса: спиртов (этанол, пентанол, бензиловый спирт, лауриловый спирт, пропиленгли-коль, глицерин), монотерпенов (D-лимонен, карвон и анисовое масло), сульфоксидов (диметилсульфок-сид), фосфолипидов (лецитин), жирных кислот (оле-иновая кислота, линолевая кислота, валериановая кислота и лауриновая кислота) и их эфиров, аминов (диэтаноламин и триэтаноламин), амидов (мочевина, диметилацетамид, диметилформамид и производ-ные пирролидона), углеводородов (алканы и сквале-ны) и поверхностно-активных веществ (ПАВ) (лау-реат натрия, цетилтриметиламмоний бромид, Brij ® , TWEEN ® и холат натрия) [12][13][14][15][16][17][18]. К активаторам переноса с хорошим потенциалом за счет наличия большого количества ненасыщенных жирных кислот относят натуральные масла (кукурузное, арахисовое и масло жожоба).…”

“…Химические усилители часто эффективны в отношении увеличения проницаемости кожи для низкомолекулярных соединений, тогда как для обеспечения и усиления транспортировки высоко-молекулярных молекул (пептидов, белков, нуклео-тидов) только химических усилителей часто бывает недостаточно, поэтому дополнительно применяют физические методы, которые основаны на элект-рическом (ионофорез и электрофорез, электропо-рация) и механическом воздействии (микроиглы) [12][13][14][15]31].…”