The Design of Experiment Approach, Rheology for Optimization of a Topical Anti-inflammatory and Analgesic Cream.

BACKGROUND: A capsaicin cream was formulated by optimizing the rheological stability, the release behavior of the drug, and the pharmacological effect. OBJECTIVES: This study aimed to: (a) apply the Design of Experiment approach to study the rheological stability and release behaviors of a drug (capsaicin) from a formulated oil-in-water cream and (b) investigate the skin irritation and anti-inflammatory and analgesic effects of the optimized cream. METHODS: The cream prepared by the emulsification method was optimized using the central composite design, and then the pharmacological effect in experimental animals was determined using Complete Freund's adjuvant (CFA). RESULTS: The effects of a permeation enhancer (X1), Vaseline (X2), and surfactants (X3) on the fluctuation of the ratio of the viscous modulus (G ') to elastic modulus (G') (tan δ) after three cycles of cooling-heating (10-40°C), flux, and skin deposition of capsaicin after 8 h on mouse skin were statistically analyzed and optimized. The final obtained CAP-cream did not cause irritation in the rabbit model and produced comparable anti-inflammatory and analgesic effects to the reference product (Voltaren® emulgel). CONCLUSION: This study successfully integrated the DoE approach, rheological science, and pharmacological studies to develop a stable and highly effective semi-solid product containing capsaicin.

Overview of epidermoid cyst.

Epidermoid cysts are slow-growing, painless masses that elevate the skin and often have a central punctum that represents the plugged orifice of the pilosebaceous follicle. On ultrasound, they have a round to oval structure, well-circumscribed, avascular mass located in subcutaneous tissue along with phenomena of dorsal acoustic amplification and lateral shadowing. On MRI, they have slightly hypointense signal intensity on T1-weighted and intermediate to high signal on T2-weighted. Restricted diffusion is typical of epidermoid cysts. These signs are useful in the differentiation of epidermal cysts from neoplastic lesions. They need early treatment as they can cause cosmetic and functional impairment.

Pharmacokinetics of a five-day oral dihydroartemisinin monotherapy regimen in patients with uncomplicated falciparum malaria.

The pharmacokinetics of dihydroartemisinin (DHA) in a 5-day oral monotherapy regimen was investigated in ten adult Vietnamese patients with uncomplicated falciparum malaria. The patients were treated with a total dose of 900 mg DHA divided as single daily doses of 300, 300, 100, 100, and 100 mg from day 0 through day 4. There were no differences in the concentrations of DHA within the first two days of treatment. The pharmacokinetics of DHA in the acute phase, however, was significantly different from that in the convalescent phase of malaria. Reduced half-life (T(1/2z)) and lower area under concentration curve (AUC(infinity)) values were observed on the final day of treatment in comparison to those obtained on the first day. These decreases in T(1/2z) and AUC(infinity) were observed in concordance with increased drug clearance (CL/F). Furthermore, the time required to reach maximum plasma DHA concentration (T(max)) on day 4 was shorter than that on day 0. Together, these findings suggest that the change in pharmacokinetics of DHA is related to the physiological change in malaria patients between the acute and convalescent phases of the disease.