Percutaneous Penetration of Methyl Nicotinate from Ointments Using the Laser Doppler Technique: Bioequivalence and Enhancer Effects

Imaging Analysis Enables Differentiation of the Distribution of Pharmaceutical Ingredients in Tacrolimus Ointments

We demonstrated the difference in the distribution state of pharmaceutical ingredients between tacrolimus (TCR) original ointment and six kinds of generic medicines. Two-dimensional imaging and depth analysis using attenuated total reflection Fourier transform infrared (ATR FT-IR) spectroscopy and confocal Raman microscopy were used, in addition to the evaluation of pharmaceutical properties, including spreading properties, rheological properties, and amount of solvent. The solvents, such as propylene carbonate and triacetin, in TCR ointments formed liquid droplets and dispersed in hydrocarbon oils. Waxes, white beeswax and beeswax, formed other domains. Confocal Raman microscopy could detect liquid droplet size without coalescence of that on germanium or glass surfaces. The combination of ATR FT-IR and confocal Raman imaging would be a powerful tool to reveal the size and shape of liquid droplets of pharmaceutical ingredients in semisolid formulations.

Skin Penetration and Permeation Properties of Transcutol®-Neat or Diluted Mixtures

A heightened interest in (trans)dermal delivery is in part driven by the need to improve the existing skin therapies and also the demand for alternative routes of administration, notably for pharmaceutical actives with undesirable oral absorption characteristics. The premise of delivering difficult actives to the skin or via the skin however is weighed down by the barrier function properties of the stratum corneum. Short of disrupting the skin by physical means, scientists have resorted to formulation with excipients known to enhance the skin penetration and permeation of drugs. A vehicle that has emerged over the years as a safe solubilizer and enhancer for a broad range of drug actives is the highly purified NF/EP grade of diethylene glycol monoethyl ether (DEGEE) commercially known as Transcutol®. Whereas numerous studies affirm its enhancing effect on drug solubilization, percutaneous absorption rate, and/or drug retention in the skin, there are few publications that unite the body of the published literature in describing the precise role and mechanisms of action for Transcutol®. In view of the current mechanistic understanding of skin barrier properties, this paper takes on a retrospective review of the published works and critically evaluates the data for potential misses due to experimental variables such as formulation design, skin model, skin hydration levels, and drug properties. The goal of this review is to mitigate the incongruence of the published works and to construct a unified, comprehensive understanding of how Transcutol® influences skin penetration and permeation. Graphical Abstract Transcutol has affinity for the hydrophilic head groups of the stratum corneum structures.

Comprehensive review on additives of topical dosage forms for drug delivery

Skin is the largest organ of the human body and plays the most important role in protecting against pathogen and foreign matter. Three important modes such as topical, regional and transdermal are widely used for delivery of various dosage forms. Among these modes, the topical dosage forms are preferred because it provides local therapeutic activity when applied to the skin or mucous membranes. Additives or pharmaceutical excipients (non-drug component of dosage form) are used as inactive ingredients in dosage form or tools for structuring dosage forms. The main use of topical dosage form additives are controling the extent of absorption, maintaining the viscosity, improving the stability as well as organoleptic property and increasing the bulk of the formulation. The overall goal of this article is to provide the clinician with information related to the topical dosage form additives and their current major applications against various diseases.

Pharmaceutical evaluation of steroidal ointments by ATR-IR chemical imaging: distribution of active and inactive pharmaceutical ingredients

We recently used micro attenuated total reflection infrared (ATR-IR) spectroscopy to conduct imaging analysis of ointments and evaluate the distributions of the active pharmaceutical ingredient (API) and excipients. An alclometasone dipropionate (ALC) ointment was used as a model product. Almeta, a brand-name product, had a domain with absorbance at 1656 cm(-1) attributable to the carbonyl group of ALC, the API. Absorbances at 1040 and 3300 cm(-1) were also noted in this domain, indicating the presence of the solubilizer, propylene glycol. Data also suggested the presence of benzyl alcohol in this domain. More detailed analysis showed the distribution of surfactants and other excipients in the base. Similar results were obtained for Vitra, a generic version of Almeta. Imaging analysis with micro ATR-IR confirmed that both ointments are liquid droplet dispersions with ALC dissolved in propylene glycol and dispersed in a base. However, minor differences in the ingredient distributions of the two ointments were detected and reflect differences in excipient concentrations and type, or manufacturing differences. In summary, we used micro ATR-IR for imaging analysis of an original ointment, Almeta, and its generic form Vitra, and established a method for visually evaluating the distributions of the API and excipients in these ointments.

Use of topical medication in orofacial neuropathic pain: a retrospective study

OBJECTIVE

The objective of this study was to evaluate the effect of topical medications as a single treatment or in combination with systemic medications in the treatment of orofacial neuropathic pain conditions.

STUDY DESIGN

A retrospective chart review of 39 patients treated for orofacial neuropathic pain at the Orofacial Pain Clinic in the New Jersey Dental School was performed. In line with the treatment selection, the subjects were divided into 3 groups: topical medications only (n = 12), systemic medications only (n = 10), and a combination of both (n = 17).

RESULTS

The starting pain level as expressed in pain Visual Analog Scale for the 3 groups was significantly different. The combined treatment group baseline pain level (7.5 +/- 0.403 SEM; P = .0015) and the systemic treatment only group pain level (8.6 +/- 0.611 SEM; P = .0375) was significantly elevated compared to the topical only group (6.1 +/- 0.716 SEM; P = .1057). Following treatment, pain level was significantly reduced in all 3 groups. The combined group had the highest pain relief (52.0 +/- 6.676 SEM % reduction; P < .0001) followed by the systemic-only group (40.6 +/- 9.727 SEM % reduction; P = .0029) and the topicals-only group (40.9 +/- 10.775 SEM% reduction; P = .0048). The time taken for the topical treatment only to act was significantly shorter (3 weeks +/- 0.479 SEM; P = .0015) when compared with the systemic-only (4 weeks +/- 0.772 SEM; P = .3629) and the combined group (5.5 weeks +/- 0.912 SEM; P = .1738).

CONCLUSION

Topical medication as single treatment or in combination with systemic medications can reduce orofacial neuropathic pain severity. Further prospective research should be performed to validate this treatment option.