The delivery of a magistral preparation must comply with the quality standards as described, among other things, in the 'Guide to Good Official Pharmaceutical Practices' and which is included in the Quality Manual (Royal Decree 21/01/2009). In this study, the Shampoo Simplex Deer Wine, prepared with Texapon® NSO, is compared in composition and physicochemical aspects with the commercially available basic shampoos of Fagron (Shampoo Fagron) and Conforma (Shampoo Simplex Conforma).
These basic shampoos are then used to create medicinal shampoos. These medicinal shampoos contain as an asset: 0.5% hexachlorophen, 1% ichtammol, 1% gift oil or 2% liquor carbonis detergent. For each medicinal shampoo it was investigated how much Cetomacrogol® 1000 is required to solubilize the medicines and how much NaCl should be added to set a suitable viscosity. The viscosity of both the basic shampoos and the medicinal shampoos was determined by the inclusion of rheograms and the calculation of the ready viscosity. In addition, a number of fundamental aspects for the formulation of shampoos are also discussed in this article.
These findings form a guideline for the pharmacist in the preparation of these medicinal shampoos. In addition to good patient information about the method of use - the pharmaceutical care aspect - the intrinsic quality of the magistral preparation is also a condition for efficacy.
DISCUSSION AND CONCLUSION
Since the different composition of the base shampoos can have a different effect on the end result of the medicinal shampoos, this study investigated on the one hand how the solubility of certain drugs can be improved and on the other hand how this can influence the viscosity of the base shampoos. Furthermore, it was investigated how the viscosity of the different medicinal shampoos can be improved by using NaCl. An overview of the optimized medicinal shampoos is shown in Table 5 (see appendix).
The results show that the basic shampoos are very different in terms of ready viscosity, but show a similar rheological behaviour. The Shampoo Simplex Red Wine NSO has the lowest ready viscosity compared to the two other commercially available base shampoos, making it easy to handle. The viscosity of the Shampoo Simplex Conforma is acceptable, while that of Fagron is the most user-friendly because of its higher viscosity. The rheological behaviour is not only important in the formulation of shampoos, but also plays a major role in many other galenic formulations and determines the user-friendliness6, 15.
The results show that the processing of medicinal products may indeed have an impact on the final result of the pharmaceutical compounding. It is also shown that NaCl plays an important role in the viscosity of the shampoos. Historically, mainly fatty acid canolamides have been used to increase the viscosity of shampoos, but it has been shown that they actually change the position of the salt curves (ready viscosity as a function of NaCl concentration), i.e. less salt is required to increase the viscosity. Other substances that can influence the viscosity in a shampoo formulation are the betaine derivatives. These form a complex with the anionic tensides to form an enlarged micell, which will then provide an increased viscosity. Furthermore, they also contribute to the NaCl concentration in a formulation, which then contributes to the viscosity build-up. NaCl is cheap and very efficient for increasing the viscosity of shampoos based on anionic tensides, i.e. the alkyl ether sulphates6, 8.
Regarding the composition of the three basic shampoos, Fagron's is more cosmetically balanced in terms of composition than the other two basic shampoos. The Shampoo Simplex Conforma and the homemade basic shampoo are simpler and contain only the most necessary additives. In the formulation of the Fagron shampoo, more attention has been paid to the sensory aspect, more specifically to the softness and aspect of the foam and the post-wash feeling of the hair, while in the formulation of the Conforma shampoo, and to a greater extent in the home-made basic shampoo, less importance is attached to these parameters. Fagron's basic shampoo is also perfumed, which can be both an advantage and a disadvantage. An advantage is a possible masking of badly scented medicines, such as tar derivatives, a disadvantage is the possible risk of allergic reactions, making it less suitable for patients with already known allergies. However, it should be noted that there are no known allergens on the list of ingredients, as required by the cosmetics legislation21. Fagron's basic shampoo also contains dyes. The colouring agents that are negatively charged may give rise to possible incompatibilities with the processing of positively charged medicines. In addition, Fagron's basic shampoo has a more acidic pH compared to the other two basic shampoos, which may influence the activity of the medicines to be processed. A disadvantage of using bronopol derivatives as a storage system is that they can lead to the formation of nitrosamines. Nitrosamines are formed from a nitrosating agent (nitrite or a
nitrite-providing compound, in this case 5-bromo-5-nitro-1,3-dioxane and a nitrosatable compound (such as fatty acid canolamides, e.g. cocamide DEA)23-25. This is also a possible explanation for the presence of an antioxidant in the basic shampoo of Fagron. It can also be noted that bronopol derivatives are only active between pH 5-918, suggesting that the storage system of Fagron shampoo is not effective. It should be added, however, that the acidity of the environment can provide partial protection against microorganisms, but that will not be powerful enough in the long run. An advantage of purchasing finished basic shampoos for the pharmacist, in addition to a possible time saving (although the home-made shampoo can be kept in stock), is the certainty of quality, in terms of composition and safety. A disadvantage for the patient is that the choice of the basic shampoo can also influence the price of the magistral preparation.
The use of hexachlorophen in topical preparations is still very rare and is already prohibited in cosmetic preparations20, 26. In the pharmaceutical sector, it has been largely replaced by chlorhexidine and iodophores because of their broader spectrum of activity, but also because of their low toxicity20, 27. In this study, the solubiliser Cetomacrogol® 1000 was chosen as it gave the best results for the findings in the manual 'Medical and Pharmaceutical Aspects in Hair Care'4 and the lowest concentration was required for solubilisation of drugs compared to other solubilisers, such as Cetiol® HE and Tween® 80. Cetiol HE was once better and Tween® 80 was always worse.
A homemade basic shampoo can also be sold by the pharmacist as such - no individual recipe - and even further optimised in terms of composition. As this is a cosmetic preparation, the European cosmetics legislation (Cosmetics Regulation EC1223/2009)21, 22 must also be complied with. This offers the consumer the guarantee that attention is paid to product development and safety28.
The advantage of medicinal shampoos is that they are cosmetically more elegant than all other scalp preparations, such as solutions, ointments and foams. They offer an easy option for the treatment of scalp disorders17. Other benefits include the cleansing aspect and time savings for the patient16, 17. In general it is recommended to apply the medicinal shampoos on damp hair and scalp and after a short massage, let them work for at least 10 minutes. After this short action on the scalp, the shampoo can be rinsed. Often the medicinal shampoos are used once or twice a week or as much as necessary. The treatment can be short term or chronic17. The duration and frequency of treatment depends on the condition and is determined by the treating physician. Recently, medicinal shampoos based on corticosteroids16 have also been marketed and one is available in Belgian pharmacies. It contains 0.05% clobetasol propionate (Clobex®, Galderma®). Additional advantages are the general advantages of magistral preparations, such as offering a tailor-made therapy.
In this article a number of medicinal shampoos have been refurbished, with the three new basic shampoos, namely the basic shampoo Shampoo Simplex Red Wine with Texapon NSO, the Shampoo Simplex Conforma and the Shampoo Fagron. For each medicinal shampoo it was investigated how much Cetomacrogol® 1000 is required to solubilize the medicines and how much NaCl should be added to set a suitable viscosity. These findings are a guide for the pharmacist in the preparation of these medicinal shampoos. In addition to good patient information about the method of use - the pharmaceutical care aspect - the quality of the magistral preparation and the user-friendliness will also have a positive effect on the patient's compliance with the therapy.
Department of Analytical Chemistry Pharmaceutical Technology
Free University of Brussels
Faculty of Medicine and Pharmacy
B-1090 Brussels, Belgium
Tel: +32(0)2 477 45 98
Fax: +32(0)2 477 47 35
Department of Analytical Chemistry and Pharmaceutical Technology
Free University of Brussels
Department of Pharmaceutical Chemistry and Drug Analysis and Medical Knowledge
Free University of Brussels
Reprinted with approval of pharmaceutical magazine for Belgium, December 2012.
The full article can be found in the Appendix