ABSTRACT
Introduction: Knowledge of morphometry of lip lining help in deciding the best site for choosing graft for its better uptake during several dermal grafting procedures following craniofacial cancers or cosmetic procedures. It also proves useful in dermatopharmacokinetics, in which we monitor the effect of drugs acting on connective tissue by translabial route and lip augmentation surgeries (esthetic surgery) where care is to be given for dermal fillers not to be injected into the muscle core of lip. Materials and Methods: Ten human male cadavers and 10 human female cadavers were procured. The rectangle‑shaped skin specimen (1 cm × 1 cm) through the upper lip was stained with hematoxylin and eosin stain. A total of 40 slides were prepared. Readings were obtained with the help of CATCAM E series HD cameras which was installed in light microscope. Results: The mean value of thickness of skin (epidermis + dermis) of the lip was 664.72 μm among males while 769.20 μm among females. Conclusion: The epithelium of females is marginally thicker than males. Edp: sc (epidermis/stratum corneum) ratio can suggest that giving drugs through translabial route will be easy in females as compared to males in the upper lip as the stratum corneum is the main barrier in drug transfusion and its absorption secondary to epidermis as a whole. The number of rete pegs per field at the dermoepidermal junction was higher in males which ensures more stability of skin of male lips compared to females
ABSTRACT
OBJECTIVE: To study the dermatopharmacokinetics of dexamethasone acetate by administering three different formulation and preparationcreams on skin of nude mouse and discuss the application prospect of the method. METHODS: At 0, 0.25, 0.75, 1.75, 3, 5, 8, 12, 24 h after administered dexamethasone acetate cream about 0.025 g on the back of the nude mice, the excess formulation was gently removed. Then mice were sacrificed at the chosen contact time points. Skin samples were immediately excised from the fixed area of skin and weighed. Both compounds were precipitated from skin homogenate with methanol. The concentrations of dexamethasone acetate in skin were analyzed by using LC-ESI-MS method. The pharmacokinetics parameters were calculated and the percutaneous absorption process in skin of nude mouse was evaluated. RESULTS: This determination method does not interfere with endogenous substances. Calibration curves were linear over the range of 0.052 4-5.24 μg · mL-1. The mean recovery was in the ranges of 89.95%-95.97%. The intra-run relative standard deviations were less than 15%. All the results showed there were no stability related problems during the samples' routine analysis. DMSO can increase the AUC value of dexamethasone acetate, coarse granularity and crystal of cream may decrease the AUC value of dexamethasone acetate. CONCLUSION: This method is fast, sensitive, accurate with good recovery, reproducibility and low detection limited, which can be successfully applied to determine the concentration of dexamethasone acetate in skin and study the dermatopharmacokinetics of nude mouse. This in vivo time-share sampling method can be used in preclinical evaluation and screening the dermatopharmacokinetics of topical drugs.
ABSTRACT
Objective To develop a novel skin microdialysis technology in vivo,and to determine the pharmacokinetic of ba-icalin after transdermal administration in rats. Methods An HPLC-MS/MS method used for the determination of baicalin in skin mi-crodialysis samples was established ,SD rats were pretreated with skin microdialysis operation under anesthesia , and then the baicalin gel was applied to the skin surface of probe in vivo.The baicalin concentration of skin microdialysates was determined , the time curve of baicalin concentration was drawn and the topical pharmacokinetics parameters of percutaneous absorption was calculated. Results Baicalin was optimized at the transitions m/z 447.3→271.2.The linearity correlation was good and the assay exhibited good precision and accuracy.The subcutaneous probe recovery of baicalin in vivo was(24.40 ±0.91)%and was stable over the 240 min study peri-od.Baicalin could be detected in the microdialysis samples after transdermal administration , and its concentration continued to rise in 8 h.AUC0-t in skin tissue was(50.04 ±34.17) mg· min· L-1. Conclusion The method of skin microdialysis in vivo could be used in the local pharmacokinetic research of baicalin.