Randomised crossover comparison of skin irritation with two transdermal oestradiol patches

Challenges and opportunities in dermal/transdermal delivery

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.

Combined ethinylestradiol/gestodene contraceptive patch: two-center, open-label study of ovulation inhibition, acceptability and safety over two cycles in female volunteers

OBJECTIVES

Determination of the ovulation inhibition efficacy of a new, transparent, transdermal, combined hormonal contraceptive patch (area 10 cm2) containing 0.9 mg ethinylestradiol and 1.9 mg gestodene in an open-label study of healthy, female volunteers (aged 18-35 years).

METHODS

A total of 199 volunteers from two centers were requested to use the contraceptive patch (one patch/week for 3 weeks, followed by 1 week of no treatment), throughout two menstrual cycles. Ovarian activity was monitored by transvaginal ultrasonography and serum hormone determinations, and classified according to the Hoogland score.

RESULTS

Ovulation inhibition was achieved in all participants (Hoogland score < 6). Secondary efficacy measures, including suppression of serum concentrations of estradiol and progesterone, and of the mid-cycle luteinizing hormone surge, confirmed ovulation inhibition. Ovulation returned in 85.7% of participants during the first cycle after cessation of treatment. There were no abnormal changes in safety parameters. A large majority of users rated the contraceptive patch as 'very convenient'.

CONCLUSIONS

This study showed that the new, combined ethinylestradiol/gestodene contraceptive patch was highly effective in reversibly inhibiting ovulation, well tolerated and regarded as 'very convenient' by the majority of users. This new, transparent, transdermal matrix patch is an attractive alternative form of contraception.

Cutaneous Reactions to Transdermal Therapeutic Systems

Transdermal therapeutic systems have been increasingly used in the past two decades. However, cutaneous side effects are fairly common and may result in poor patient compliance. This review article summarizes the spectrum of reactions due to transdermal therapeutic systems and provides a current list of known allergens.

Aerodiol versus the transdermal route: perspectives for patient preference

OBJECTIVE

to compare the efficacy, tolerability and user preference of Aerodiol intranasal and transdermal patch administration of 17 beta-estradiol for climacteric symptoms.

METHODS

an open-label, multicenter, crossover trial in which recently postmenopausal women were randomized to receive either Aerodiol 300 microg daily (n=176), or transdermal 17 beta-estradiol (reservoir patches delivering 50 microg/day), 2 patches per week (n=185), for 12 weeks, followed by 4 weeks of the alternative treatment. Efficacy was assessed primarily by the Kupperman index at the end of each treatment period. User satisfaction was assessed by questionnaire at weeks 12 and 16, and at week 16 the women chose which treatment they preferred to use for a further 40-week period.

RESULTS

Aerodiol and transdermal patch therapy produced marked and similar reductions in the Kupperman index and the incidence of hot flushes at weeks 12 and 16. The reduction in the Kupperman index at week 12 was statistically equivalent for the two treatments. The tolerability of both treatments was good, with similar numbers of emergent adverse events reported in both groups. The incidence of moderate or severe mastalgia, however, was significantly lower with Aerodiol (P=0.02). Significantly more women chose to continue treatment with Aerodiol than with the transdermal patch (66 vs. 34%, P<0.001). When all women had experienced both treatments, reported levels of satisfaction were significantly higher with Aerodiol than with transdermal therapy (P<0.001 for all six categories assessed).

CONCLUSIONS

Aerodiol and transdermal patch treatments were of similar efficacy and tolerability. Levels of user preference and satisfaction, however, were higher with Aerodiol, which should contribute towards good long-term compliance with this therapy.

Serum concentrations of 17beta-estradiol and estrone after multiple-dose administration of percutaneous estradiol gel in symptomatic menopausal women

In two multicenter phase III efficacy studies, blood samples were obtained to evaluate the serum concentrations of 17beta-estradiol (E2) and unconjugated estrone (E1) after administration of a percutaneous gel or transdermal patch containing estradiol. In postmenopausal women, normal laboratory E2 and E1 serum concentrations range from 10-30 pg/mL and 20-40 pg/mL, respectively. Study subjects were healthy postmenopausal women with moderate to severe hot flushes occurring at least seven times daily or 60 times per week. Study 1 was a randomized, double-blind, multicenter study of percutaneous E2 gel 1.25 or 2.5 g (0.75 and 1.5 mg E2, respectively) versus placebo gel. Study 2 was a double-blind (blinded to E2 gel dose), randomized, active-controlled, multicenter, 12-week phase 3 study of E2 gel 0.625, 1.25, or 2.5 g (0.375, 0.75, or 1.5 mg E2, respectively) versus a transdermal E2 patch delivering 0.05 mg E2 per day. Serum E2 and E1 concentrations were evaluated at baseline and at week 12 for study 1 and at baseline and weeks 4, 8, and 12 for study 2 using radioimmunoassay. Median serum concentrations of E2 after 1.25- and 2.5-g gel administration appeared to be dose-proportional throughout both studies. In study 1, the median serum concentrations of E2 at week 12 were 33.5 and 65.0 pg/mL for 1.25- and 2.5-g gel dose, respectively. The corresponding E1 values were 49.0 and 58.0 pg/mL. In study 2, both E2 and E1 concentrations were relatively stable at weeks 4, 8, and 12. E2 values at week 12 for 0.625-, 1.25-, and 2.5-g gel doses and E2 patch were 25.0, 32.0, 60.0, and 38.5 pg/mL, respectively. The corresponding E1 values were 39.0, 41.0, 62.5, and 40.0 pg/mL. Application of the 1.25-g gel dose and a transdermal patch delivering 50 microg per day of E2 resulted in comparable median E2 and E1 concentrations. However, the 0.625-g gel dose did not produce E2 levels in a range expected to be consistently therapeutic in most postmenopausal women.

Transdermal drug delivery systems and skin sensitivity reactions. Incidence and management

Transdermal devices are now marketed for the delivery of systemic medication through the skin. Advantages associated with transdermal drug delivery include avoidance of first-pass metabolism and variable absorption as well as improved patient compliance. Drugs currently available by this route include scopolamine, nitroglycerin (glyceryl trinitrate), estradiol, nicotine, clonidine, fentanyl, and testosterone. This novel development has brought about a specific constellation of skin problems which vary widely in incidence between drugs. It is important to vary the site of drug administration to minimize these reactions. Any eczematous reaction can be treated with a moderately potent topical corticosteroid. Patients with topical sensitivity are usually tolerant of oral challenge but systemic sensitization has been reported and caution is still advocated before proceeding to this step. The increasing use of transdermal drug delivery systems across many specialities means that problems of skin sensitivity are of growing relevance to the dermatologist, the hospital specialist, and the primary care physician.

Improved patient acceptability with a transdermal drug-in-adhesive oestradiol patch

The aim of this trial was to assess the relative patient acceptability of two transdermal oestradiol patches used in treatment of oestrogen deficiency in postmenopausal women. Thirty-five hysterectomised postmenopausal women with no previous experience of transdermal oestradiol delivery systems received treatment with either once-weekly drug-in-adhesive (DIA) patches or twice-weekly reservoir patches for 4 weeks, and were then switched to the alternative treatment for a further 4 weeks. At the end of the study, the patients completed a questionnaire to assess their relative preference for a number of characteristics of the 2 transdermal systems and, where possible, their preference for transdermal compared with oral hormone replacement therapy. Thirty-one patients completed the study; four withdrew during treatment with the reservoir patch. The DIA patch was preferred for being 'easiest to remember to apply' by 80% of patients (p < 0.01), 'easiest to open' and 'easiest to apply' by 68% (p = 0.025), and as having 'best cosmetic appearance' by 65% (p = 0.05) and 'best overall skin adhesion' by 61% (p < 0.01). While 10% of patients rated the reservoir patch as 'least irritating to the skin' (p = 0.03), only one patient found this patch 'most comfortable to wear' (p < 0.01). The DIA patch was selected by 87% of patients as their preferred treatment overall (p = 0.001). Ninety-one per cent of 22 responding patients were at least as confident of treatment with transdermal patches as with oral hormone replacement therapy (p = 0.006) and 74 % of 27 responders preferred transdermal to oral treatment (p = 0.004). The DIA patch appears to be more acceptable to patients than the reservoir patch as a transdermal oestradiol delivery system for the treatment of postmenopausal oestrogen deficiency. Characteristics of the DIA patch which may account for improved patient acceptance include ease of remembering once-weekly patch application, improved cosmetic appearance and comfort, and better adhesion.

Significant differences in estradiol bioavailability from two similarly labelled estradiol matrix transdermal systems

OBJECTIVE

To compare the bioavailabilities of estradiol delivered by two transdermal estradiol matrix systems; Alora and Evorel.

STUDY DESIGN

A single-center, open-label, randomized, two-period cross-over study in 33 postmenopausal women. The subjects received two successive 84-h applications of either Alora or Evorel (each labelled to deliver 50 micrograms/day 17 beta-estradiol) in a randomized sequence. Serial serum samples, collected over the 84-h period following the application of the second patch, were analyzed for estradiol using a validated radioimmunoassay method.

RESULTS

The fluctuation index produced by Evorel was significantly higher than that produced by Alora (Evorel, 135%; Alora, 76%; p < 0.0005). In addition, the estradiol baseline-corrected area under the curve for Evorel was significantly lower than that for Alora (Alora, 2871.8 pg h/ml; Evorel, 1870.6 pg h/ml; p < 0.0005). Both patches were found to be generally well tolerated.

CONCLUSION

Alora delivered a higher, more consistent concentration of estradiol into the systemic circulation over the entire dosing interval than did Everol. Although the full clinical significance of these findings is currently unknown, this study demonstrates that there are significant differences in estradiol delivery from these two products, although they are labelled with the same nominal delivery rate.

Experience with transdermal testosterone replacement therapy for hypogonadal men

BACKGROUND

None of the existing options for long-term testosterone replacement therapy (TRT) for hypogonadal men are ideal. Depot replacement at frequent intervals and implants are effective but invasive and inconvenient for the patient. Oral therapy results in poor hormone levels. Both are associated with undesirable metabolic changes. A transdermal formulation therefore represents a potential therapeutic advance for testosterone replacement.

OBJECTIVE

To carry out a clinical audit of the acceptability and efficacy as a treatment for hypogonadism of the first transdermal testosterone therapy available in the UK (Andropatch, SmithKline Beecham) compared with existing androgen replacement options.

PATIENTS AND MEASUREMENTS

Serum testosterone and questionnaire data on treatment efficacy, side-effects, therapy preference, sexual dysfunction and partner's attitudes to therapy were obtained from 50 hypogonadal men prescribed long-term testosterone replacement.

RESULTS

Eighty per cent of the men returned analysable questionnaires. Eighty-four per cent experienced adverse effects with transdermal therapy, most commonly dermatological problems; 22% of the sample elected to continue with transdermal therapy, 72% returned to depot and 5% returned to oral therapy. The reservoir patches were judged to be too large, uncomfortable, visually obtrusive and noisy. Testosterone levels were comparable to those obtained with depot replacement with the added advantage of a more physiological pharmacokinetic profile. Men taking oral preparations were consistently under-replaced.

CONCLUSIONS

Adverse events were substantially higher than reported from clinical trials but in keeping with the spectrum of yellow card reports received by the Committee on Safety of Medicines. The pharmacokinetic advantages are thus largely outweighed by low patient acceptability. In its present form transdermal therapy remains an expensive option for those who cannot tolerate depot testosterone replacement.

Transdermal delivery of estradiol in postmenopausal women with a novel topical aerosol

The objective of this study was to determine if a novel metered-dose topical aerosol (MDTA) formulation containing the new dermal penetration enhancer, padimate O, could enhance the transdermal delivery of estradiol to an extent that would result in clinically relevant plasma concentrations. The estradiol MDTA (with padimate O) was applied once daily at 0800 h to postmenopausal women for 9 days, and plasma estradiol and estrone was measured daily (24 h postapplication) by radioimmunoassay. The topical dose was administered as three 1 mg doses of estradiol, each applied as a single spray over 10 cm2 which were placed adjacent to each other on the subject's ventral forearm. None of the subjects tested showed any sign of skin irritation at the application site over the entire study period using the Draize irritation score. In four postmenopausal women (age 54-63 years, weight 67-93 kg) the mean estradiol level 24 h postapplication over the 9 day study period was 53 pg/mL. This result was significantly greater (p < 0.001) than the baseline value of 13 pg/mL. The mean estradiol/estrone ratio also rose significantly (p < 0.04) from a baseline value of 0.2 up to 0.8. We conclude that this novel MDTA formulation significantly enhances the transdermal delivery of estradiol to allow a clinically relevant dose of estradiol to be delivered in postmenopausal women with once daily dosing.