Transdermal delivery formulations creams

In addition to traditional dermal and transdermal delivery formulations, such as creams, ointments, gels, and patches, several other systems have been evaluated. In the pharmaceutical semisolid and liquid formulation area,these include sprays, foams, multiple emulsions, microemulsions, liposomal formulations, transfersomes, niosomes, ethosomes, cyclodextrins, glycospheres, dermal membrane structures, and microsponges. Many of these novel systems use vesicles to modulate drug delivery. Novel transdermal... 

Transdermal delivery of certain APIs is now common for the treatment of some medical conditions, and there are several excipients that are promoted as transdermal penetration enhancers. One of the earlier materials developed was laurocapram (Azone ). There is a detrimental interaction between laurocapram and mineral oil (liquid paraffin) whereby when both are included in the same formulation, the skin penetration-enhancing properties of laurocapram are lost. Such interactions have implications for extemporaneous mixing of different cream and ointment formulations in the pharmacy. 

The formulation additives strongly impact on transdermal delivery as the variety of dosage forms, such as creams, ointments, lotions, gels, and patches offer a wide variety of formulation additives. The problems related to the crystallization of drugs, as discussed tmder suspension dosage forms, also apply here... 

The efficacy of diazepam applied topically in emulsion creams depends greatly on the oil droplet size and to a lesser degree on the formulation composition and the oil type. Emulsions as vehicles for transdermal delivery of diazepam generate significant systemic activity of the drug as compared with conventional ointments. The efficacy of this formulation was shown to be as effective as in the range of parenteral delivery against convulsive effects induced by penta-methylenetetrazole in mice (77). 

The formulation in which the candidate drug is applied to the skin is another important factor that can affect its bioavailability. In transdermal drug delivery, a number of vehicles may be used, such as creams, ointments, lotions, gels and so on. The solubility of the compound in... 

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