Diss. (sammanfattning) Stockholm : Karol. inst., 2003. / Härtill 5 uppsatser.

Acne affects as many as 80% of young adults and adolescents all over the world. This detrimental condition can be classified into four stages: (a) open comedo (blackhead), (b) closed comedo (whitehead), (c) papule and (d) pustule (Russell, 2000:357-366). There are various factors that can lead to acne outbreaks which include: (a) hormone level changes during the menstrual cycle in women, (b) certain drugs (i.e. lithium), (c) certain cosmetics and (d) environmental conditions such as humidity (University of Maryland, 2009:1). The skin performs a variety of functions which include the two major functions: (a) the containment and (b) the protection of the internal organs of the body. The containment function relates specifically to the ability of the skin to confine the underlying tissues and restrain their movement from place to place. The protective function, on the other hand, relates to the ability of the skin to act as a microbiological barrier to most micro-organisms; a chemical barrier to exogenous chemical compounds; barrier to radiation and electrical shock; and mechanical barrier to impact (Danckwerts, 1991:315). Niacinamide and salicylic acid were chosen in combination, due to the beneficial effects that they have on acne. Niacinamide has an anti-inflammatory action on acne; which reduces redness, dryness and irritation caused by Propioni-bacterium acnes that live in the clogged pores of pimples (Acnetreatmentlab, 2008:1). Salicylic acid is a keratolytic and keratoplastic agent. It is used in combination with other ingredients to enhance the shedding of corneocytes. This causes penetration into the skin to be very difficult (SAMF, 2005:177). The solubility of niacinamide and salicylic acid in PBS (pH 7.4 at 32°C) were 212.95 mg/ml and 4.07 mg/ml, respectively. The log D values of niacinamide and salicylic acid were determined to be -0.32 and 0.33, respectively. According to the solubility of niacinamide and salicylic acid it was expected that both of the active ingredients would permeate through the skin. However, it is expected that niacinamide will depict enhanced permeation with respect to salicylic acid. The results of the log D for both of the active ingredients indicate that there would not be optimal permeation. This study involved the formulation of four different acne preparations (Pheroid™cream, Pheroid™gel, cream and gel), combining niacinamide and salicylic acid. The evaluation of stability parameters for the different formulations indicated that none of the formulations was stable under the different storage conditions determined by the Medicines Control Council. Nevertheless, the cream and gel were the most stable of the four formulations. Visual assessment of the Pheroid™ formulations with the confocal laser scanning microscopy (CLMS) was conducted and inconclusive evidence to whether the active substances were entrapped within the Pheroids™, was obtained. Franz cell diffusion studies indicated that the cream (in the case of niacinamide) and gel (in the case of salicylic acid) depicted the highest average and median flux from hours 6 to 12. Results of the tape stripping studies showed that with the gel formulation, concentrations of 2.060 ug/ml and 44.749 ug/ml niacinamide were obtained in the epidermis and dermis respectively. After the Pheroid™ gel was applied, tape stripping depicted only 1.587 ug/ml niacinamide in the epidermis with respect to 22.764 ug/ml niacinamide in the dermis. The cream formulation, on the other hand, showed niacinamide concentrations of 2.001 ug/ml in the epidermis and 13.363 ug/ml in the dermis, whereas with the Pheroid™ cream formulation, concentrations of 1.097 ug/ml and 18.061 ug/ml were obtained in the epidermis and dermis respectively. Tape stripping results depicted that with the gel formulation, concentrations of 2.113 ug/ml and 49.519 ug/ml salicylic acid were obtained in the epidermis and dermis respectively, whereas the Pheroid™ gel formulation showed salicylic acid, concentrations of 1.114 ug/ml in the epidermis and 95.360 ug/ml in the dermis. The cream formulation, however, depicted salicylic acid concentrations of 0.758 ug/ml in the epidermis and 44.729 ug/ml in the dermis. Lastly, after the Pheroid™ cream was applied, salicylic acid concentrations of 0.411 ug/ml and 48.424 ug/ml in the epidermis and dermis respectively, were measured. It could, therefore, be concluded that both niacinamide and salicylic acid tend to concentrate more in the dermis, irrespective of the formulation. This may be an advantage since acne is usually targeted in the dermis and epidermis. / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2010.

Acne is a common skin disease that affects the follicular unit of the skin. Inflammatory- and noninflammatory forms of acne exist. The most affected areas on the body include the face, upper part of the chest and the back. These are the areas with the most sebaceous follicles. Acne occurs when hyperkeratinisation causes the cells of the hair follicle to shed too fast. These cells then block the follicle opening. Thus, sebum cannot pass through the hair follicle onto the skin. The human skin is composed of three layers, namely the epidermis, which acts as a waterproof layer and a barrier to infections; the dermis, which contains the skin appendages; and the subcutaneous fat layer. Skin acts as a protective layer against pathogens and damage to the body. It also provides a semi-impermeable barrier to prevent water loss. Azelaic acid and niacinamide are both currently used in the treatment of acne. Azelaic acid is a saturated dicarboxylic acid which is used to treat mild to moderate acne. It has antibacterial, keratolytic and comedolytic properties. Niacinamide, on the other hand, is the amide of nicotinic acid and is beneficial in the treatment of both papular and pustular acne. It has a demonstrated anti-inflammatory action and causes dose-dependent inhibition of sebocyte secretions. The Pheroid™ delivery system is a colloidal system that consists of even lipid-based submicron-and micron-sized structures that are very unique in nature. This technology is able to improve the absorption and/or efficacy of various active ingredients, as well as other compounds. In this study, a cream, Pheroid™ cream, a gel and a Pheroid™ gel were formulated, containing both azelaic acid and niacinamide. Stability tests were conducted on these formulations for six months, and it was established that none of the formulations were stable under the different storage conditions. Tests that were conducted during stability testing, as determined by the Medicines Control Council, included: assay, mass variation, appearance, viscosity, pH determination and confocal laser scanning microscopy (CLSM). Diffusion studies (12 hours long in total) with vertical Franz cells were conducted with Caucasian female skin obtained after abdominoplastic surgery. Tape-stripping followed in order to establish the epidermis and dermis concentrations of azelaic acid and niacinamide. Significant concentrations of both active ingredients were found in the epidermis and the dermis after 12 hours. / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2010.

Acne affects as many as 80% of young adults and adolescents all over the world. This detrimental condition can be classified into four stages: (a) open comedo (blackhead), (b) closed comedo (whitehead), (c) papule and (d) pustule (Russell, 2000:357-366). There are various factors that can lead to acne outbreaks which include: (a) hormone level changes during the menstrual cycle in women, (b) certain drugs (i.e. lithium), (c) certain cosmetics and (d) environmental conditions such as humidity (University of Maryland, 2009:1). The skin performs a variety of functions which include the two major functions: (a) the containment and (b) the protection of the internal organs of the body. The containment function relates specifically to the ability of the skin to confine the underlying tissues and restrain their movement from place to place. The protective function, on the other hand, relates to the ability of the skin to act as a microbiological barrier to most micro-organisms; a chemical barrier to exogenous chemical compounds; barrier to radiation and electrical shock; and mechanical barrier to impact (Danckwerts, 1991:315). Niacinamide and salicylic acid were chosen in combination, due to the beneficial effects that they have on acne. Niacinamide has an anti-inflammatory action on acne; which reduces redness, dryness and irritation caused by Propioni-bacterium acnes that live in the clogged pores of pimples (Acnetreatmentlab, 2008:1). Salicylic acid is a keratolytic and keratoplastic agent. It is used in combination with other ingredients to enhance the shedding of corneocytes. This causes penetration into the skin to be very difficult (SAMF, 2005:177). The solubility of niacinamide and salicylic acid in PBS (pH 7.4 at 32°C) were 212.95 mg/ml and 4.07 mg/ml, respectively. The log D values of niacinamide and salicylic acid were determined to be -0.32 and 0.33, respectively. According to the solubility of niacinamide and salicylic acid it was expected that both of the active ingredients would permeate through the skin. However, it is expected that niacinamide will depict enhanced permeation with respect to salicylic acid. The results of the log D for both of the active ingredients indicate that there would not be optimal permeation. This study involved the formulation of four different acne preparations (Pheroid™cream, Pheroid™gel, cream and gel), combining niacinamide and salicylic acid. The evaluation of stability parameters for the different formulations indicated that none of the formulations was stable under the different storage conditions determined by the Medicines Control Council. Nevertheless, the cream and gel were the most stable of the four formulations. Visual assessment of the Pheroid™ formulations with the confocal laser scanning microscopy (CLMS) was conducted and inconclusive evidence to whether the active substances were entrapped within the Pheroids™, was obtained. Franz cell diffusion studies indicated that the cream (in the case of niacinamide) and gel (in the case of salicylic acid) depicted the highest average and median flux from hours 6 to 12. Results of the tape stripping studies showed that with the gel formulation, concentrations of 2.060 ug/ml and 44.749 ug/ml niacinamide were obtained in the epidermis and dermis respectively. After the Pheroid™ gel was applied, tape stripping depicted only 1.587 ug/ml niacinamide in the epidermis with respect to 22.764 ug/ml niacinamide in the dermis. The cream formulation, on the other hand, showed niacinamide concentrations of 2.001 ug/ml in the epidermis and 13.363 ug/ml in the dermis, whereas with the Pheroid™ cream formulation, concentrations of 1.097 ug/ml and 18.061 ug/ml were obtained in the epidermis and dermis respectively. Tape stripping results depicted that with the gel formulation, concentrations of 2.113 ug/ml and 49.519 ug/ml salicylic acid were obtained in the epidermis and dermis respectively, whereas the Pheroid™ gel formulation showed salicylic acid, concentrations of 1.114 ug/ml in the epidermis and 95.360 ug/ml in the dermis. The cream formulation, however, depicted salicylic acid concentrations of 0.758 ug/ml in the epidermis and 44.729 ug/ml in the dermis. Lastly, after the Pheroid™ cream was applied, salicylic acid concentrations of 0.411 ug/ml and 48.424 ug/ml in the epidermis and dermis respectively, were measured. It could, therefore, be concluded that both niacinamide and salicylic acid tend to concentrate more in the dermis, irrespective of the formulation. This may be an advantage since acne is usually targeted in the dermis and epidermis. / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2010.

Acne is a common skin disease that affects the follicular unit of the skin. Inflammatory- and noninflammatory forms of acne exist. The most affected areas on the body include the face, upper part of the chest and the back. These are the areas with the most sebaceous follicles. Acne occurs when hyperkeratinisation causes the cells of the hair follicle to shed too fast. These cells then block the follicle opening. Thus, sebum cannot pass through the hair follicle onto the skin. The human skin is composed of three layers, namely the epidermis, which acts as a waterproof layer and a barrier to infections; the dermis, which contains the skin appendages; and the subcutaneous fat layer. Skin acts as a protective layer against pathogens and damage to the body. It also provides a semi-impermeable barrier to prevent water loss. Azelaic acid and niacinamide are both currently used in the treatment of acne. Azelaic acid is a saturated dicarboxylic acid which is used to treat mild to moderate acne. It has antibacterial, keratolytic and comedolytic properties. Niacinamide, on the other hand, is the amide of nicotinic acid and is beneficial in the treatment of both papular and pustular acne. It has a demonstrated anti-inflammatory action and causes dose-dependent inhibition of sebocyte secretions. The Pheroid™ delivery system is a colloidal system that consists of even lipid-based submicron-and micron-sized structures that are very unique in nature. This technology is able to improve the absorption and/or efficacy of various active ingredients, as well as other compounds. In this study, a cream, Pheroid™ cream, a gel and a Pheroid™ gel were formulated, containing both azelaic acid and niacinamide. Stability tests were conducted on these formulations for six months, and it was established that none of the formulations were stable under the different storage conditions. Tests that were conducted during stability testing, as determined by the Medicines Control Council, included: assay, mass variation, appearance, viscosity, pH determination and confocal laser scanning microscopy (CLSM). Diffusion studies (12 hours long in total) with vertical Franz cells were conducted with Caucasian female skin obtained after abdominoplastic surgery. Tape-stripping followed in order to establish the epidermis and dermis concentrations of azelaic acid and niacinamide. Significant concentrations of both active ingredients were found in the epidermis and the dermis after 12 hours. / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2010.

Thesis (M.D. with Distinction in Research) -- University of Texas Southwestern Medical Center at Dallas, 2006. / Partial embargo. Vita. Bibliography: 44-46

Background: Niacinamide (NIA) is one of the most commonly used cosmetic ingredients. It belongs to the vitamin-B3 family and has extensive dermatological therapeutic benefits. NIA has been proven to be a useful skincare product in serving as anti-acne agent, preventing skin hyperpigmentation, removal of wrinkles from the face etc.  Aim: To investigate permeability patterns of NIA, its effect on electrical impedance of the skin membrane and the role it plays in maintaining the hydration of stratum corneum (SC). For this, permeation, chromatography, sorption isotherm and X-ray studies were performed. Results: NIA permeation was observed to correlate with pH and it permeated more when delivered in PBS at pH 7.4 as compared to its permeation in citrate buffer at pH 5. Moreover, skin resistance also increased by Ca. 47% in relation to NIA permeation at pH-5 while it decreased by an average of 45% at pH 7.4. In addition, vapor sorption analysis showed that NIA increased the hydration of SC at 95%RH as compared to buffer controls. This was also supported by X-ray data where NIA treated SC samples were shown to have larger interchain spacing in their keratin filaments in comparison to SC in buffer controls. This increase is usually associated with an increase in the water content of SC and thus NIA might have similar beneficial effects as water and can even be more advantageous as it doesn’t evaporate in dehydrated states unlike water. Moreover, artificial skin model has also been tested in parallel, and it was significantly more permeable to NIA than the human skin. Hence some modifications are necessary before it can be used to replace human/porcine skin. Conclusion: The study showed that pH influences NIA permeation and resistance of skin membrane. Additionally, NIA play beneficial roles by increasing water content of SC at high relative humidity (RH%).

Diss. (sammanfattning) Linköping : Linköpings universitet, 2010. / Härtill 4 uppsatser.

No / The purpose of this work was to explore NIR spectroscopy as a PAT tool to monitor the formation of ibuprofen and nicotinamide cocrystals during extrusion based solvent free continuous cocrystallization (SFCC). Drug and co-former were gravimetrically fed into a heated co-rotating twin screw extruder to form cocrystals. Real-time process monitoring was performed using a high temperature NIR probe in the extruder die to assess cocrystal content and subsequently compared to off-line powder X-ray diffraction measurements. The effect of processing variables, such as temperature and mixing intensity, on the extent of cocrystal formation was investigated. NIR spectroscopy was sensitive to cocrystal formation with the appearance of new peaks and peak shifts, particularly in the 4800-5200 cm(-1) wave-number region. PXRD confirmed an increased conversion of the mixture into cocrystal with increase in barrel temperature and screw mixing intensity. A decrease in screw rotation speed also provided improved cocrystal yield due to the material experiencing longer residence times within the process. A partial least squares analysis in this region of NIR spectrum correlated well with PXRD data, providing a best fit with cocrystal conversion when a limited range of process conditions were considered, for example a single set temperature. The study suggests that NIR spectroscopy could be used to monitor cocrystal purity on an industrial scale using this continuous, solvent-free process.