Skin patch formulation

A self-adhesive skin patch formulation which releases the opioid fentanyl (25 mg/h for 72 h) transdermally is also available for pain relief in palliative care. 

Nicotine patches are applied to the skin, and deliver nicotine through the skin at a relatively steady rate. There are currently four patch formulations on the market in the USA and many other countties that vary in their design, pharmacokinetics, and duration of wear (i.e., 24- and 16-h wear). The diversity in patch systems has been described in reviews (Henningfield 1995 Gorsline 1993), and the differences in pharmacokinetics have been illustrated in a head-to-head clinical trial... 

PG fluxes into the receptor chamber following delivery across hairless mouse skin from formulations (a) and (b) are shown in Figures 3 and 4, respectively. PG association with EPC liposomes [(b)] lowers by one-half the transdermal delivery of the drug when compared to the free patch [(a)]. 

The seven dmgs and the combination estrogen-progestin product presently approved in the US for delivery by the transdermal route were all well known and available in more conventional dosage forms before their formulation into skin patches . All of these dmgs are extremely potent, none requiring more than about 20 mg per day (and some, much less) for effective therapy. 

Transdermal clonidine formulated in adhesive skin patches has been used for long-term treatment with... 

Nitrates can be administered by various routes. For example, glyceryl trinitrate is used not only as traditional sublingual tablets but also in the form of modified-release tablets, buccal tablets, aerosolized oral spray, intravenous injection, and topical ointment or skin patches for percutaneous absorption (23). These different formulations have been developed largely as a means of controlling the onset and duration of action of glyceryl trinitrate, since in conventional oral form its action is limited by marked hepatic first-pass metabolism. 

Current androgenic formulations for TRT largely are restricted to injectable formulations of testosterone esters, transdermal delivery formulations (scrotal or nonscrotal patches or gel), or buccal testosterone. Marketed injectable forms of testosterone esters (e.g., testosterone enanthate, propionate, or cypionate) produce undesirable fluctuations in testosterone blood levels, with supraphysiological concentrations early and subphysiological levels toward the end of the period before the next injection. These fluctuations provide an unsatisfactory benefits profile and, in some cases, undesired side effects. Skin patches provide a better blood level profile of testosterone, but skin irritation and daily application limit the usefulness and acceptability of this form of therapy. Oral... 

Occlusion of semi-solid preparations may be useful if systemic absorption is desired. A careful risk-benefit evaluation is then required. Transdermal patches are a more elegant alternative. Being virtually painless and easy to apply, if they achieve controlled delivery, they provide a formulation of choice for prolonged-release systemic uptake. They would have to be adapted to skin maturation, formulated with adhesives with low allergenic potential and be available in different strengths. Of course, the same inter- and intra-patient variability in relation to sites of administration and skin condition occurs in children as in adults. 

SKIN A case series of three patients who were formulation and developmental scientists at pharmaceutical companies working with oxycodone described episodic erythema of their eyelids and erythematous patches along their wrists that occurred at e workplace and resolved every time they left work [63 ]. All three patients rmderwent skin patch testing that revealed a contact dermatitis due to oxycodone. 

A 27-year-old woman, a pharmacist, had dermatitis on three separate occasions a few hours after she started to take oral deflazacort 6 mg for vesicular hand eczema (185). On each occasion, her symptoms included a widespread macular rash mainly on the inner aspects of her arms and legs and buttocks. She also had severe scaling, fever, nausea, vomiting, malaise, and hypotension. A skin biopsy was consistent with erythema multiforme, and direct immunofluorescence showed granular deposits at the dermoepidermal junction. Patch tests to the commercial formulation of deflazacort 6 mg (1% aqueous solution) and to pure deflazacort (1% aqueous solution) were positive, but there were no cross-reactions to other glucocorticoids. 

Poor adhesion and skin irritation, with erythema and itching, are the principal drawbacks of transdermal therapy (225). Skin irritation can be overcome in some cases by changing the application site every day. In a direct comparison of transdermal patches, the duration, severity, and number of skin reactions depended on the individual formulation and excipients. 

Ethanol is used in many transdermal formulations and is often the solvent of choice for incorporation into patches. As with water, ethanol permeates rapidly through human skin with a steady-state flux of approximately 1 mg/cm2/h [31]. 

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