Dermatologica 156: 224-230 (1978)
Comparative Blanching Activities of Proprietary Diflucortolone Valerate Topical Preparations G.L. C oleman , I. K anfer and J.M. H aigh School of Pharmaceutical Sciences, Rhodes University, Grahamstovvn
Key Words. Blanching activity • Topical corticosteroids • Diflucortolone valerate topical preparations • Fluocinolone acetonidc topical preparations Abstract. The blanching activities and hence bioavailabilities of the cream, ointment and fatty ointment preparations of Nerisone® and Temetex® (diflucortolone valerate 0.1%) were evaluated using an occluded and unoccluded blanching assay. These products were compared to Synalar® ointment and cream (fluocinolone acetonide 0.025%), established topical corticosteroid preparations. Statistical analysis showed no significant differences between similar formulations of diflucortolone valerate. Significant differences were noted between diflucortolone valerate and fluocinolone acetonide preparations.
Temetex and Nerisone are both available as cream, ointment and fatty ointment formulations containing 0.1% diflucortolone valerate. It is a wellestablished fact that the nature of the base affects both the rate of release of the active ingredient and the therapeutic effect in topical corticosteroid therapy, e.g., cream bases have a low fat and high water content making them suitable for acute and weeping conditions. Although both Nerisone and Temetex contain the same corticosteroid in the same concentration, it has previously been shown [2, 3] that this does not necessarily imply bio equivalence of the active ingredient. The aim of the present study was, therefore, to compare the blanching activities of the different formulations to ascertain whether there is any difference in the rate of release of diflucortolone valerate from the same type of base compounded by different manufacturers, and also to compare the
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Received: July 11, 1977; accepted: August 19, 1977.
Blanching Activities of Diflucortolone Valerate Preparations
225
rates of release of the steroid from the three different types of base. Ointment and cream formulations of fluocinolone acetonide were included in order that a comparative potency could be ascribed to the difluocortolone valerate preparations. Materials and Method Tubes of Nerisone fatty ointment, ointment and cream (prepared in Germany), Temetex fatty ointment, ointment and cream (prepared in Switzerland) and Synalar oint ment and cream (prepared in South Africa) were purchased from a local pharmacy. Two trials were performed using a modified McKenzie-Stoughton blanching assay [1]. In the first trial the blanching activities of Nerisone ointment and fatty ointment were compared with those produced by Temetex ointment and fatty ointment. The degree of blanching produced by Synalar ointment was also monitored. In the second trial Nerisone cream was compared with Temetex cream. Also included were Synalar cream and Neri sone ointment. The inclusion of the latter formulation allowed for intercomparison be tween the two trials. 10 human volunteers were used per trial. The flexor aspects of the forearms were masked producing 12 7 mm square application sites per arm. A standard mass (approximately 4 mg) of each preparation was applied to the application sites in a random manner. For each volunteer both arms were used, one set of applications being occluded using a non-porous plastic film, the other being left unoccluded but protected with a cardboard frame in order to prevent spreading. 6 h after application the maskings and frames were removed and the forearms washed with soap and warm water. The arms were evaluated independently using a double-blind technique by three observers at various time intervals adequate to establish a blanching profile. The averaged readings of all observers were used to analyse the data. The results were statistically analysed using three methods. (a) Number o f sites exhibiting blanching. This method involved a yes/no determination of whether or not blanching was evident at each application site. (b) Intensity o f blanching. A visual determination of the degree of blanching produced at each site was made by this method. A response scale was defined as follows: 0 = n o blanching; 1= faint pallor, clear outline of application site not visible; 2 = moderate blanching, square outline of application site clearly visible; 3 = intense blanching over the whole application site. The percent total possible score (%TPS) was calculated using the following method. The maximum score per site is equal to 3. For 10 volunteers each having z sites per arm and three independent observers, TPS = 3 x 10x z x 3, %TPS =
actual score x 100. TPS
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(c) Paired comparison o f adjacent application sites. This method involved the direct comparison of different formulations applied as pairs. For each pair the following decision was required. One site exhibited a greater degree of blanching, both sites showed equal blanching or blanching was not observed at either site.
226
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The data obtained from (a) and (c) were analysed by x2 techniques. A 2 x 2 contingency table was examined employing Yates’ correction factor for continuity for results from (a), whereas the x 2 procedure of McNemar was used for results from (c). The data obtained from (b) were tabulated for each product and application mode. Since a four point inten sity score was used, a 2 x 4 contingency table was obtained for each of the product com parisons. Three degrees of freedom were assumed. Area under the curve (AUC) measurements were also utilized.
Results and Discussion
Figures 1 and 2 depict the blanching profiles obtained for both the oint ment and fatty ointment preparations in the occluded and unoccluded modes, respectively. Figures 3 and 4 depict the blanching profiles obtained for the cream formulations (including Nerisone ointment) in the occluded and unoccluded modes, respectively. Table I lists the blanching responses for each formulation.
O = □ = O = □ =
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Fig. 1. Blanching profiles of occluded ointments. • = Temetex ointment; Nerisone ointment; A = Temetex fatty ointment; A = Nerisone fatty ointment; Synalar ointment. Fig. 2. Blanching profiles of unoccluded ointments. • = Temetex ointment; Nerisone ointment; ▲ = Temetex fatty ointment; A = Nerisone fatty ointment; Synalar ointment.
Blanching Activities of Diflucortolone Valerate Preparations
227
X2 analysis showed significant differences in favour of both Nerisone and Temetex ointments relative to Synalar ointment from the 7- to 18-hour range in both the occluded and unoccluded modes. From 18 to 28 h after appli cation, fluocinolone acetonide displays its longer acting effect. There are few statistically significant differences between the ointment and fatty oint ment formulations in either the occluded or unoccluded application mode. There are no statistically significant differences between Nerisone and Temetex ointments or between Nerisone and Temetex fatty ointments in either mode of application. The blanching profiles indicate that diflucortolone valerate shows a more rapid rate of release from the vehicle associated with a higher degree of blanching and a more rapid removal from the site of action when compared to fluocinolone acetonide in both cream and ointment formulations. The rapidity of onset of blanching caused by diflucortolone valerate has pre viously been demonstrated [5], In the case of the creams, no statistically significant differences were noted between Nerisone and Temetex in either application mode. Both of these
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Fig. 3. Blanching profiles of occluded creams. A = Temetex cream; • = Nerisone cream; A = Synalar cream; O = Nerisone ointment. Fig. 4. Blanching profiles of unoccluded creams. A = Temetex cream; • = Nerisone cream; A = Synalar cream; o = Nerisone ointment.
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preparations and Synalar cream show statistical equivalence until about 13 h after application in both the occluded and unoccluded modes. From 13 to 28 h after application Synalar cream shows significant differences over Nerisone and Temetex creams. No significant differences were observed between Nerisone ointment and cream in the occluded mode. In the unoccluded mode of application Nerisone ointment demonstrated a higher degree of blanching when compared to Nerisone cream. This is expected because of the occlusive nature of the ointment base. AUC data have been reported in a number of ways, the more usual being summed % TPS and AUC percent x time. Frequently, the terminal reading is taken before the response has reached zero hence only a relative or un corrected AUC value can be calculated [2]. In order to overcome this a correction factor may be defined as follows: (AUC)o-oo = (AUC)o-3h + (AUC) 3h-a,
and
(AUQgh.*
(Cp)ph Ke ’
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where (Cp)ph is the response at the last sampling time and Ke the elimination rate constant determined from the terminal portion of a semi-log plot of response vs. time [4]. AUC values obtained from the blanching profiles are analogous with blood concentration vs. time curves for oral and parenteral preparations and are therefore of use in defining the bioavailability of the preparations studied [1]. The difference in the bioavailability relationship between the corrected and uncorrected AUC values should not be so marked if the same steroid is used in the same type of formulation. If however different steroids are used, then large differences in the bioavailability will be observed when using corrected AUC values as opposed to uncorrected values. This is due to the differences in the pharmacokinetic nature of the various synthetic corticosteroids. Pharmacokinetic differences will also be observed between different for mulations of the same corticosteroid. From table I when the corrected and uncorrected AUC values are compar ed it can be seen that fluocinolone acetonide has a longer duration of action than diflucortolone valerate. This is more marked in the ointments than in the creams. The table also emphasises that there is little difference between the same formulations of diflucortolone valerate prepared by different manufacturers.
Blanching Activities of Diflucortolonc Valerate Preparations
229
Table I. Blanching responses to formulations tested Summed %TPS
Uncorrected AUC
Corrected AUC
Occluded ointments Synalar ointment Temetex ointment Nerisone ointment Temetex fatty ointment Nerisone fatty ointment
235.7 406.8 382.9 353.7 352.5
591.9 987.3 917.3 836.5 833.7
793.3 1 020.9 923.4 846.5 841.9
Unoccluded ointments Synalar ointment Temetex ointment Nerisone ointment Temetex fatty ointment Nerisone fatty ointment
199.1 316.0 324.8 264.9 259.3
540.9 752.2 775.4 648.4 617.9
610.8 790.0 814.8 682.5 646.4
Occluded creams Synalar cream Temetex cream Nerisone cream
405.7 353.7 368.1
971.9 796.2 822.8
998.8 798.8 833.4
Unoccluded creams Synalar cream Temetex cream Nerisone cream
276.5 173.7 196.8
670.6 384.5 458.7
700.7 386.7 462.4
Ackno wledgemen ts We wish to acknowledge a grant from the South African Medical Research Council. One of us (G.L.C.) acknowledges a bursary from the South African Council for Scientific and Industrial Research.
References 1 B arry, B.W.: Bioavailability of topical steroids. Dermatológica 152: suppl. 1, pp.
47-65 (1976). 2 Goldman, M .F.; Lockerbie, L., and L aws, E.A .: The evaluation of a novel corti
Downloaded by: Lund University Libraries 130.235.66.10 - 9/5/2017 5:40:55 AM
costeroid formulation, fluocinonide in FAPG base, in the blanching test. Br. JT. Derm. 85: 573-576 (1971).
230
Coleman/K anfer/H aigh
3 L evy, G.: Biopharmaceutical concerns and commitments. Drug Inf. Bull. 1: 115-118 (1969). 4 S lywka , G.W.A.; M elikian, A.P., Straughan , A.B.; W hyatt, P.L., and M eyer, M .C.: Bioavailability of eleven sulphisoxazole products in humans. J. pharm. Sci. 65: 1494-1498 (1976). 5 Szadurski, J.; R enz , F., and G asser, D.: Onset of the vasoconstrictor efTect of diflucortolone valerate, betamethasone valerate and fluocinolone acetonide ointments applied for varying periods under occlusive dressings. Dermatológica 153: 236-242 (1976).
Downloaded by: Lund University Libraries 130.235.66.10 - 9/5/2017 5:40:55 AM
Dr. I. K anfer, School of Pharmaceutical Sciences, Rhodes University, 6140 Grahamstown (Republic of South Africa)
Comparative Blanching Activities of Proprietary Diflucortolone Valerate Topical Preparations G.L. C oleman , I. K anfer and J.M. H aigh School of Pharmaceutical Sciences, Rhodes University, Grahamstovvn
Key Words. Blanching activity • Topical corticosteroids • Diflucortolone valerate topical preparations • Fluocinolone acetonidc topical preparations Abstract. The blanching activities and hence bioavailabilities of the cream, ointment and fatty ointment preparations of Nerisone® and Temetex® (diflucortolone valerate 0.1%) were evaluated using an occluded and unoccluded blanching assay. These products were compared to Synalar® ointment and cream (fluocinolone acetonide 0.025%), established topical corticosteroid preparations. Statistical analysis showed no significant differences between similar formulations of diflucortolone valerate. Significant differences were noted between diflucortolone valerate and fluocinolone acetonide preparations.
Temetex and Nerisone are both available as cream, ointment and fatty ointment formulations containing 0.1% diflucortolone valerate. It is a wellestablished fact that the nature of the base affects both the rate of release of the active ingredient and the therapeutic effect in topical corticosteroid therapy, e.g., cream bases have a low fat and high water content making them suitable for acute and weeping conditions. Although both Nerisone and Temetex contain the same corticosteroid in the same concentration, it has previously been shown [2, 3] that this does not necessarily imply bio equivalence of the active ingredient. The aim of the present study was, therefore, to compare the blanching activities of the different formulations to ascertain whether there is any difference in the rate of release of diflucortolone valerate from the same type of base compounded by different manufacturers, and also to compare the
Downloaded by: Lund University Libraries 130.235.66.10 - 9/5/2017 5:40:55 AM
Received: July 11, 1977; accepted: August 19, 1977.
Blanching Activities of Diflucortolone Valerate Preparations
225
rates of release of the steroid from the three different types of base. Ointment and cream formulations of fluocinolone acetonide were included in order that a comparative potency could be ascribed to the difluocortolone valerate preparations. Materials and Method Tubes of Nerisone fatty ointment, ointment and cream (prepared in Germany), Temetex fatty ointment, ointment and cream (prepared in Switzerland) and Synalar oint ment and cream (prepared in South Africa) were purchased from a local pharmacy. Two trials were performed using a modified McKenzie-Stoughton blanching assay [1]. In the first trial the blanching activities of Nerisone ointment and fatty ointment were compared with those produced by Temetex ointment and fatty ointment. The degree of blanching produced by Synalar ointment was also monitored. In the second trial Nerisone cream was compared with Temetex cream. Also included were Synalar cream and Neri sone ointment. The inclusion of the latter formulation allowed for intercomparison be tween the two trials. 10 human volunteers were used per trial. The flexor aspects of the forearms were masked producing 12 7 mm square application sites per arm. A standard mass (approximately 4 mg) of each preparation was applied to the application sites in a random manner. For each volunteer both arms were used, one set of applications being occluded using a non-porous plastic film, the other being left unoccluded but protected with a cardboard frame in order to prevent spreading. 6 h after application the maskings and frames were removed and the forearms washed with soap and warm water. The arms were evaluated independently using a double-blind technique by three observers at various time intervals adequate to establish a blanching profile. The averaged readings of all observers were used to analyse the data. The results were statistically analysed using three methods. (a) Number o f sites exhibiting blanching. This method involved a yes/no determination of whether or not blanching was evident at each application site. (b) Intensity o f blanching. A visual determination of the degree of blanching produced at each site was made by this method. A response scale was defined as follows: 0 = n o blanching; 1= faint pallor, clear outline of application site not visible; 2 = moderate blanching, square outline of application site clearly visible; 3 = intense blanching over the whole application site. The percent total possible score (%TPS) was calculated using the following method. The maximum score per site is equal to 3. For 10 volunteers each having z sites per arm and three independent observers, TPS = 3 x 10x z x 3, %TPS =
actual score x 100. TPS
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(c) Paired comparison o f adjacent application sites. This method involved the direct comparison of different formulations applied as pairs. For each pair the following decision was required. One site exhibited a greater degree of blanching, both sites showed equal blanching or blanching was not observed at either site.
226
Coleman/K anfer/H aigh
The data obtained from (a) and (c) were analysed by x2 techniques. A 2 x 2 contingency table was examined employing Yates’ correction factor for continuity for results from (a), whereas the x 2 procedure of McNemar was used for results from (c). The data obtained from (b) were tabulated for each product and application mode. Since a four point inten sity score was used, a 2 x 4 contingency table was obtained for each of the product com parisons. Three degrees of freedom were assumed. Area under the curve (AUC) measurements were also utilized.
Results and Discussion
Figures 1 and 2 depict the blanching profiles obtained for both the oint ment and fatty ointment preparations in the occluded and unoccluded modes, respectively. Figures 3 and 4 depict the blanching profiles obtained for the cream formulations (including Nerisone ointment) in the occluded and unoccluded modes, respectively. Table I lists the blanching responses for each formulation.
O = □ = O = □ =
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Fig. 1. Blanching profiles of occluded ointments. • = Temetex ointment; Nerisone ointment; A = Temetex fatty ointment; A = Nerisone fatty ointment; Synalar ointment. Fig. 2. Blanching profiles of unoccluded ointments. • = Temetex ointment; Nerisone ointment; ▲ = Temetex fatty ointment; A = Nerisone fatty ointment; Synalar ointment.
Blanching Activities of Diflucortolone Valerate Preparations
227
X2 analysis showed significant differences in favour of both Nerisone and Temetex ointments relative to Synalar ointment from the 7- to 18-hour range in both the occluded and unoccluded modes. From 18 to 28 h after appli cation, fluocinolone acetonide displays its longer acting effect. There are few statistically significant differences between the ointment and fatty oint ment formulations in either the occluded or unoccluded application mode. There are no statistically significant differences between Nerisone and Temetex ointments or between Nerisone and Temetex fatty ointments in either mode of application. The blanching profiles indicate that diflucortolone valerate shows a more rapid rate of release from the vehicle associated with a higher degree of blanching and a more rapid removal from the site of action when compared to fluocinolone acetonide in both cream and ointment formulations. The rapidity of onset of blanching caused by diflucortolone valerate has pre viously been demonstrated [5], In the case of the creams, no statistically significant differences were noted between Nerisone and Temetex in either application mode. Both of these
Downloaded by: Lund University Libraries 130.235.66.10 - 9/5/2017 5:40:55 AM
Fig. 3. Blanching profiles of occluded creams. A = Temetex cream; • = Nerisone cream; A = Synalar cream; O = Nerisone ointment. Fig. 4. Blanching profiles of unoccluded creams. A = Temetex cream; • = Nerisone cream; A = Synalar cream; o = Nerisone ointment.
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Coleman/K anfer/H aigh
preparations and Synalar cream show statistical equivalence until about 13 h after application in both the occluded and unoccluded modes. From 13 to 28 h after application Synalar cream shows significant differences over Nerisone and Temetex creams. No significant differences were observed between Nerisone ointment and cream in the occluded mode. In the unoccluded mode of application Nerisone ointment demonstrated a higher degree of blanching when compared to Nerisone cream. This is expected because of the occlusive nature of the ointment base. AUC data have been reported in a number of ways, the more usual being summed % TPS and AUC percent x time. Frequently, the terminal reading is taken before the response has reached zero hence only a relative or un corrected AUC value can be calculated [2]. In order to overcome this a correction factor may be defined as follows: (AUC)o-oo = (AUC)o-3h + (AUC) 3h-a,
and
(AUQgh.*
(Cp)ph Ke ’
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where (Cp)ph is the response at the last sampling time and Ke the elimination rate constant determined from the terminal portion of a semi-log plot of response vs. time [4]. AUC values obtained from the blanching profiles are analogous with blood concentration vs. time curves for oral and parenteral preparations and are therefore of use in defining the bioavailability of the preparations studied [1]. The difference in the bioavailability relationship between the corrected and uncorrected AUC values should not be so marked if the same steroid is used in the same type of formulation. If however different steroids are used, then large differences in the bioavailability will be observed when using corrected AUC values as opposed to uncorrected values. This is due to the differences in the pharmacokinetic nature of the various synthetic corticosteroids. Pharmacokinetic differences will also be observed between different for mulations of the same corticosteroid. From table I when the corrected and uncorrected AUC values are compar ed it can be seen that fluocinolone acetonide has a longer duration of action than diflucortolone valerate. This is more marked in the ointments than in the creams. The table also emphasises that there is little difference between the same formulations of diflucortolone valerate prepared by different manufacturers.
Blanching Activities of Diflucortolonc Valerate Preparations
229
Table I. Blanching responses to formulations tested Summed %TPS
Uncorrected AUC
Corrected AUC
Occluded ointments Synalar ointment Temetex ointment Nerisone ointment Temetex fatty ointment Nerisone fatty ointment
235.7 406.8 382.9 353.7 352.5
591.9 987.3 917.3 836.5 833.7
793.3 1 020.9 923.4 846.5 841.9
Unoccluded ointments Synalar ointment Temetex ointment Nerisone ointment Temetex fatty ointment Nerisone fatty ointment
199.1 316.0 324.8 264.9 259.3
540.9 752.2 775.4 648.4 617.9
610.8 790.0 814.8 682.5 646.4
Occluded creams Synalar cream Temetex cream Nerisone cream
405.7 353.7 368.1
971.9 796.2 822.8
998.8 798.8 833.4
Unoccluded creams Synalar cream Temetex cream Nerisone cream
276.5 173.7 196.8
670.6 384.5 458.7
700.7 386.7 462.4
Ackno wledgemen ts We wish to acknowledge a grant from the South African Medical Research Council. One of us (G.L.C.) acknowledges a bursary from the South African Council for Scientific and Industrial Research.
References 1 B arry, B.W.: Bioavailability of topical steroids. Dermatológica 152: suppl. 1, pp.
47-65 (1976). 2 Goldman, M .F.; Lockerbie, L., and L aws, E.A .: The evaluation of a novel corti
Downloaded by: Lund University Libraries 130.235.66.10 - 9/5/2017 5:40:55 AM
costeroid formulation, fluocinonide in FAPG base, in the blanching test. Br. JT. Derm. 85: 573-576 (1971).
230
Coleman/K anfer/H aigh
3 L evy, G.: Biopharmaceutical concerns and commitments. Drug Inf. Bull. 1: 115-118 (1969). 4 S lywka , G.W.A.; M elikian, A.P., Straughan , A.B.; W hyatt, P.L., and M eyer, M .C.: Bioavailability of eleven sulphisoxazole products in humans. J. pharm. Sci. 65: 1494-1498 (1976). 5 Szadurski, J.; R enz , F., and G asser, D.: Onset of the vasoconstrictor efTect of diflucortolone valerate, betamethasone valerate and fluocinolone acetonide ointments applied for varying periods under occlusive dressings. Dermatológica 153: 236-242 (1976).
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Dr. I. K anfer, School of Pharmaceutical Sciences, Rhodes University, 6140 Grahamstown (Republic of South Africa)
