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Öğe The effects of abdominal and bimanual pelvic examination and transvaginal ultrasonography on serum CA-125 levels(2000) Sari R.; Buyukberber S.; Sevinc A.; Ates M.; Balat O.; Hascalik S.; Turk M.The need for the early detection of ovarian cancer continues to be one of the most important issues in women's health care. The three most extensively evaluated screening methods for ovarian cancer are pelvic examination, transvaginal ultrasonography, and serum CA-125 levels. The answers to questions such as should the levels of CA-125 be measured before bimanual pelvic examination or transvaginal ultrasonography or do abdominal examinations effect the levels of CA-125 are obscure. Fifty-four otherwise healthy female volunteers at the preovulatory phase of the menstrual cycle complaining of vaginal candidiasis were divided into 3 groups. Abdominal (group 1), bimanual pelvic (group 2), and transvaginal ultrasonography (group 3) examination was performed and serum CA-125 levels were evaluated prior to examination and 10 minutes, 6 hours, and 24 hours after the examination. As a result, serum CA-125 levels (U/ml) were found to be 8.13 ± 4.76, 8.23 ± 5.05, 8.32 ± 4.88, and 8.33 ± 4.94 in the group of abdominal examination, respectively, 8.23 ± 4.89, 8.45 ± 5.15, 8.77 ± 4.96, and 8.79 ± 5.50 in the group of bimanual pelvic examination, respectively, and 8.19 ± 4.56, 8.30 ± 5.10, 8.81 ± 5.56, and 8.88 ± 5.71 in the group of transvaginal ultrasonography, respectively. The serum CA-125 levels detected prior to examinations were statistically insignificant when compared with the results obtained at 10 minutes, 6 hours, and 24 hours later in all three groups. We concluded that physical examination, either abdominal or pelvic, and transvaginal ultrasonography do not change the serum levels of CA-125.Öğe Evaluation of Pharmacokinetics and Biodistribution of Targeted Nanoparticles(Taylor and Francis, 2021) Ates M.; Izat N.; Kir F.; Gulsun T.; Sahin S.Nanotechnology attracts more attention day by day in the field of pharmacy as in many fields. This chapter discusses the biodistribution and pharmacokinetic (PK) properties of nanoparticles, the factors affecting these properties, and studies for assessment. Physiologically based pharmacokinetic modeling (PBPK) is a powerful descriptive tool that mechanistically describes the PK and/or pharmacodynamic behaviors of drugs by using models and simulations with combined considerations of physiology, population, and drug characteristics. The chapter highlights PBPK applications for the PK evaluation and formulation development of nanoparticles. PBPK models are valuable tools to understand and predict the in vivo reflection of changes in formulation design and development factors. Using the dissolution- and distribution-based model, the observed in vivo situation was described successfully by establishing an in vitro–in vivo correlation between physicochemical characteristics of the formulation and clinical data. © 2022 Jenny Stanford Publishing Pte. Ltd.Öğe Physicochemical and pharmacokinetic properties of acyclovir(Nova Science Publishers, Inc., 2023) Sahin S.; Ates M.Acyclovir (2-amino-9-(2-hydroxyethoxymethyl)-1H-purin-6-one) is an antiviral drug that is a guanine nucleoside analogue. The molecule was discovered in 1974. Clinical trials started in 1977, and it was marketed for the first time in 1981. Since then, acyclovir has become one of the most used antiviral drugs worldwide. It was included in the WHO Model List of Essential Medicines in October 2013. It is used in the treatment of herpes simplex viruses, varicella-zoster virus, Epstein-Barr virus and cytomegalovirus. After acyclovir uptake, it is converted to acyclovir monophosphate by thymidine kinase. Since this transformation occurs in infected cells, the specificity of drug increases. Cellular enzymes convert the acyclovir monophosphate to acyclovir triphosphate. Acyclovir triphosphate inhibits DNA polymerase, inhibiting DNA synthesis and viral replication. Acyclovir is commercially available as tablets (200 mg, 400 mg, and 800 mg), oral suspension (400 mg/5 mL), topical cream (5%), intravenous injection (25 mg/mL, sodium salt), and ophthalmic ointment (3%). Acyclovir is slightly soluble in water (1.2-1.6 mg/mL at 22-25°C) and its solubility affected by pH (2.3 mg/mL at pH 5.8). Although aqueous solubility of acyclovir is more than 100 mg/mL at 25°C, it is nonionic at pH 7.4 (maximum solubility 2.5 mg/mL at 37°C). Acyclovir is an amphoteric molecule with two pKa values (2.27 and 9.25). Acyclovir is classified as Class III (high solubility, low permeability/poor metabolism) drug according to Biopharmaceutics Classification System (BCS), and Class IV for the Biopharmaceutics Drug Disposition Classification System (BDDCS). Absorption of acyclovir is slow, variable and insufficient, and its oral bioavailability is low (10-30%). Maximum plasma concentration is reached within 1.5-2.5 hours. After multiple dosing, steady-state concentration is reached within 1-2 days. Acyclovir is widely distributed in many body tissues including lung, brain, kidney, spleen, heart, liver, muscle, placenta and uterus. The protein binding of acyclovir is 9-33% and the volume of distribution is 48 L/1.73 m2. The main route of elimination is renal excretion as unchanged drug via glomerular filtration and tubular secretion. Acyclovir is metabolized in the liver (8-14%) and converted to its pharmacologically inactive metabolite 9-(carboxymethoxy)methyl] guanine. The half-life is about 2.5 hours. Acyclovir is well tolerated, but some adverse effects such as nausea, vomiting, diarrhea, and headache may occur depending on the route of administration. In addition, skin rash and contact dermatitis can be seen in topical applications. Intravenous infusion may cause nephropathy and phlebitis due to crystallization in the renal tubules. Acute renal failure can develop very rarely. In this chapter, physicochemical and pharmacokinetic properties of acyclovir will be given in detail. © 2024 Nova Science Publishers, Inc.
