Combination therapy for cerebral ischemia: do progesterone and noscapine provide better neuroprotection than either alone in the treatment?

Ischemic stroke presents multifaceted pathological outcomes with overlapping mechanisms of cerebral injury. High mortality and disability with stroke warrant a novel multi-targeted therapeutic approach. The neuroprotection with progesterone (PG) and noscapine (NOS) on cerebral ischemia-reperfusion (I-R) injury was demonstrated individually, but the outcome of combination treatment to alleviate cerebral damage is still unexplored. Randomly divided groups of rats (n = 6) were Sham-operated, I-R, PG (8 mg/kg), NOS (10 mg/kg), and PG + NOS (8 mg/kg + 10 mg/kg). The rats were exposed to bilateral common carotid artery occlusion, except Sham-operated, to investigate the therapeutic outcome of PG and NOS alone and in combination on I-R injury. Besides the alterations in cognitive and motor abilities, we estimated infarct area, oxidative stress, blood-brain barrier (BBB) permeability, and histology after treatment. Pharmacokinetic parameters like Cmax, Tmax, half-life, and AUC0-t were estimated in biological samples to substantiate the therapeutic outcomes of the combination treatment. We report PG and NOS prevent loss of motor ability and improve spatial memory after cerebral I-R injury. Combination treatment significantly reduced inflammation and restricted infarction; it attenuated oxidative stress and BBB damage and improved grip strength. Histopathological analysis demonstrated a significant reduction in leukocyte infiltration with the most profound effect in the combination group. Simultaneous analysis of PG and NOS in plasma revealed enhanced peak drug concentration, improved AUC, and prolonged half-life; the drug levels in the brain have increased significantly for both. We conclude that PG and NOS have beneficial effects against brain damage and the co-administration further reinforced neuroprotection in the cerebral ischemia-reperfusion injury.

Pharmacokinetics, safety and bioequivalence of two formulations of progesterone soft capsule in healthy Chinese postmenopausal females: Impacts of a high-fat meal.

Progesterone is an important natural hormone regulating ovulation and menstruation. The present study aimed to investigate the pharmacokinetics and safety of two formulations of progesterone in Chinese postmenopausal females under fasting and fed conditions. The study adopted a single-dose, open-label, randomized, three-period bioequivalence design. A total of 96 subjects were enrolled and randomly assigned to the fasting cohort or fed cohort. A high-fat meal (890 kcal) was used in the fed study. The reference-scaled average bioequivalence method was used for bioequivalence evaluation. A high-fat meal led to a 22-fold higher peak concentration (Cmax ) and a 7-fold higher area under the curve (AUC) while time to reach Cmax and half-life was not significantly affected. The concentration-time curve displayed double peaks suggesting the existence of enterohepatic circulation. The test/reference geometric mean ratios for Cmax and AUC under fasting and fed conditions are all within the range of 80% to 125%. All adverse events (AEs) that occurred during the trial were mild and did not cause drop-out, though these AEs occurred more frequently under fed state. In conclusion, the two formulations of progesterone are bioequivalent in Chinese subjects under fasting and fed conditions. Drug label modification regarding food effects needs further discussion.

Prediction of Free Drug Absorption in Cyclodextrin Formulation by a Modified Physiologically Based Pharmacokinetic Model and Phase Solubility 3-D Surface Graph.

PURPOSE: Cyclodextrin (CD) is commonly used to enhance the solubility of oral drugs. However, with the increase of CD concentrations, the fraction of free drug molecules decreases, which may potentially impede drug absorption. This study aims to predict the optimal ratio between drug and CD to achieve the best absorption efficiency by computational simulation. METHODS: First, a physiologically based pharmacokinetic (PBPK) model was developed. This model can continuously adjust absorption according to free drug fraction and was validated against two model drugs, progesterone (PG) and andrographolide (AG). The further analysis involves 3-D surface graphs to investigate the relationship between free drug amount, theoretically absorbable concentration, and contents of drug and CD in the formulation. RESULTS: The PBPK model predicted the PK behavior of two drugs well. The concentration ratio of drug to CD, leading to maximal free drug amount and the best absorption efficiency, is nearly the same as the slope determined in the phase solubility test. The new modified PBPK model and 3-D surface graph can easily predict the absorption difference of formulations with various drug/CD ratios. CONCLUSION: This PBPK model and 3-D surface graph can predict the absorption and determine the optimal concentration ratio of CD formulation, which could accelerate the R&D of CD formulation.

Sex steroid hormone receptors of telocytes - potential key role in leiomyoma development.

BACKGROUND: Uterine leiomyoma is the most widespread benign tumor affecting women of childbearing age. There are still gaps in the understanding of its pathogenesis. Telocytes are unique cells found in more than 50 different locations inside the human body. The functional relationship between cells could clarify the pathogenesis of leiomyomata. Examination of membrane receptors on telocytes could explain their role in fibrosis, oxidative stress, and myometrial contractility. AIM: This research was conducted to assess the density of telocytes in terms of their putative role in leiomyoma formation by focusing on their correlation with the expression of estrogen and progesterone receptors. METHODS: For gross evaluation of uterine tissue samples from leiomyoma, routine histology of adjacent and unaffected myometrium was performed. Immunohistochemical analysis of c-kit, tryptase, CD34, PDGFRα (telocyte-specific), and ER and PRs (estrogen and progesterone receptors) was performed to examine uterine telocytes and the expression of sex steroid receptors. RESULTS: The decline in telocyte density in leiomyoma foci was correlated with high progesterone expression and low estrogen receptor expression. The unchanged myometrium showed the opposite correlation and balance between both steroid hormone receptors. The difference in sex steroid receptor expression is correlated with the density of uterine telocytes, which emphasizes their conductor function. CONCLUSIONS: A reduction in telocyte density and the changes in examined marker expression demonstrate the involvement of telocytes in local homeostasis. The expression of membrane receptors explicitly indicates their functional potential in the human myometrium, focusing attention on contractility and local homeostasis.

Copolymer Composition and Nanoparticle Configuration Enhance in vitro Drug Release Behavior of Poorly Water-soluble Progesterone for Oral Formulations.

HYPOTHESIS: Developing oral formulations to enable effective release of poorly water-soluble drugs like progesterone is a major challenge in pharmaceutics. Coaxial electrospray can generate drug-loaded nanoparticles of strategic compositions and configurations to enhance physiological dissolution and bioavailability of poorly water-soluble drug progesterone. EXPERIMENTS: Six formulations comprising nanoparticles encapsulating progesterone in different poly(lactide-co-glycolide) (PLGA) matrix configurations and compositions were fabricated and characterized in terms of morphology, molecular crystallinity, drug encapsulation efficiency and release behavior. FINDINGS: A protocol of fabrication conditions to achieve 100% drug encapsulation efficiency in nanoparticles was developed. Scanning electron microscopy shows smooth and spherical morphology of 472.1±54.8 to 588.0±92.1 nm in diameter. Multiphoton Airyscan super-resolution confocal microscopy revealed core-shell nanoparticle configuration. Fourier transform infrared spectroscopy confirmed presence of PLGA and progesterone in all formulations. Diffractometry indicated amorphous state of the encapsulated drug. UV-vis spectroscopy showed drug release increased with hydrophilic copolymer glycolide ratio while core-shell formulations with progesterone co-dissolved in PLGA core exhibited enhanced release over five hours at 79.9±1.4% and 70.7±3.5% for LA:GA 50:50 and 75:25 in comparison with pure progesterone without polymer matrix in the core at 67.0±1.7% and 57.5±2.8%, respectively. Computational modeling showed good agreement with the experimental drug release behavior in vitro.

Colon-targeting of progesterone using hybrid polymeric microspheres improves its bioavailability and in vivo biological efficacy.

This study aims to enhance progesterone (PG) oral bioavailability via its incorporation into hybrid colon-targeted pectin/NaCMC microspheres (MS) cross-linked with Zn2+ and Al3+. The MS were characterized for particle morphology, encapsulation efficiency, swelling behavior, drug release, mucoadhesivity and colon-specific degradability. Response-surface methodology was adopted to optimize the fabrication conditions. Enhancement of in vivo drug performance was evaluated through pharmacokinetic and pharmacodynamic studies. The optimized formulation was typically spherical with a mean diameter of 1031 µm and drug entrapment efficiency of 88.8%. This formulation exhibited pH-dependent swelling, negligible drug release in simulated gastric fluid and sustained-release pattern in simulated small intestinal fluid with a mean t50% of 26.5 h. It also showed prolonged and preferential adhesion to rat colonic mucosa, as well as expedited degradation in presence of rat caecal contents. The MS significantly increased the area under the curve and mean residence time by 1.8 and 2.3-fold, respectively compared to the free drug. Orally administered MS showed ~10 times increase in myometrial thickness compared with the drug suspension and elicited uterine responses very similar to that obtained parenterally. These results confirm the ability of this new carrier system to improve the oral bioavailability of PG and attain adequate clinical efficacy.

Pharmacokinetics of hard micronized progesterone capsules via vaginal or oral route compared with soft micronized capsules in healthy postmenopausal women: a randomized open-label clinical study.

PURPOSE: This study aimed to evaluate the pharmacokinetics of hard micronized progesterone capsules (Yimaxin) via the vaginal or oral route compared with soft micronized progesterone capsules (Utrogestan) in a Chinese population. METHODS: A prospective single-center randomized open-label trial was conducted in 16 healthy postmenopausal women. They were randomized into two groups to receive four phases of treatment: vaginal Yimaxin, vaginal Utrogestan, oral Yimaxin, or oral Utrogestan, with different sequences. RESULTS: By the vaginal route, steady-state maximum concentration (Cmax) of Yimaxin and Utrogestan was 29.13±8.09 and 12.30±1.60 mg/L, time to Cmax 9.72±10.50 and 11.03±9.62 hours, central compartment volume of distribution 4.26±1.86 and 10.40±2.32 L, clearance rate 0.18±0.05 and 0.38±0.10 L/h, and AUC 261.42±74.36 and 116.83±19.72 h·ng/mL, respectively. By the oral route, Cmax of Yimaxin and Utrogestan was 62.97±40.59 and 169.53±130.24 mg/L, time to Cmax was 2.88±1.35 and 2.06±1.55 hours, central compartment volume of distribution 132.16±52.13 and 85.08±55.07 L, clearance rate 3.43±1.07 and 2.50±1.04 L/h, and AUC 274.86±160.28 and 472.00±250.54 h·ng/mL, respectively. By the vaginal route, Cmax, minimum concentration, AUC0-72, and AUC of Yimaxin were higher than Utrogestan, while by the oral route the Cmax, AUC0-72, and AUC of Utrogestan were higher than Yimaxin. CONCLUSION: Pharmacokinetic parameters were different between Yimaxin and Utrogestan on vaginal and oral administration. By the oral route, the metabolism and absorption of Utrogestan was superior to Yimaxin, while by the vaginal route Yimaxin was superior.

In vivo study on biotransformation of pentacyclic analogs of progesterone: Identification of their metabolites by HPLC-MS method.

Progesterone derivatives containing the D' additional cyclohexane ring in the 16α,17α-positions of steroid core (pregna-D'-pentaranes) exhibited high in vitro and in vivo selective progestogenic activity. The assessment of their biotransformation in the body, and the identification of possible metabolites are integral parts of a potential drug studies. Here we describe the results of in vivo metabolic transformation of 6α-methyl-16α,17α-cyclohexanopregn-4-ene-3,20-dione 1 and its 6-demethylated analog 2 and identification of their metabolites in rat urine. We synthesized and fully characterized (1D and 2D NMR, HRMS) 11 possible metabolites as the standards. Then we developed the LC-MS/MS assay including sample preparation and chromatography conditions for identification of the detected metabolites of 1 and 2. The 5α- and 5ß-3,20-diketo-, 3ß-hydroxy-20-keto-5α-, 3-keto-20(S)-hydroxy-5α-, 3ß,20(S)-dihydroxy-5α-metabolites of compounds 1 and 2 were found in rat urine samples. The starting steroids 1 and 2, as well as both 3ß,20(R)-dihydroxy metabolites were not detected in the examined biological urine samples. Thus, we demonstrate for the first time that exogenous progestines - pregna-D'-pentaranes - and endogenous progesterone follow similar metabolic pathways. Therefore, despite the presence of an additional ring D' and the methyl group in position 6, the main enzymatic transformations are similar to those of the natural hormone.

Pharmacokinetics of vaginal progesterone in pregnancy.

BACKGROUND: Characterization of pharmacokinetics is lacking for vaginal progesterone in pregnancy. Dosing of vaginal progesterone for preterm birth prevention has been empirical. Owing to pregnancy-related changes in vaginal and uterine blood flow, hepatic metabolism, renal clearance, and endogenously elevated serum progesterone, studies outside of pregnancy may not be applicable. The lack of the pharmacokinetics profile of vaginally administered progesterone in pregnancy limits the ability to define the exposure-response relationship needed to optimize dosing, which has implications for its use in research and clinical care regarding management of short cervix, prevention of recurrent preterm birth, and prevention of recurrent miscarriage. OBJECTIVE: This was a study to establish the feasibility of using serum progesterone to establish basic pharmacokinetic parameters of vaginal progesterone in pregnancy for preterm birth prevention. STUDY DESIGN: This is a prospective study of 6 low-risk singletons at 18 0/7 to 23 6/7 weeks' gestation with body mass index 20-40. Exclusion criteria were current vaginitis, abnormal Pap smear, prescription medication use, cervical length ≤25 mm, prior preterm birth, and contraindication to progesterone. Participants received a single dose of 200 mg micronized vaginal progesterone and serum progesterone levels were evaluated every 2 hours from 0 to 12 hours and then 24 hours post dose. Primary outcome was concentration/time profile of serum progesterone. RESULTS: Median (range) maternal age was 27 (21.5-33.3) years, median body mass index was 26.5 (23.3-29.0) kg/m2, and median gestational age was 22.9 (21.0-23.4) weeks. Median baseline serum progesterone was 47 (40-52) ng/mL, median peak concentration was 54 (48-68) ng/mL, and median time to peak was 12 (4-15) hours. There was a trend in rising serum progesterone over baseline with a median change in peak concentration of 11 ng/mL and interquartile range of 2-22. Median percent change from baseline was an increase by 24% (interquartile range, 4%-53%). However, there was no clear elimination phase and the median area under the curve was 112 ng*h/mL with an interquartile range of -43 to 239. CONCLUSION: Unlike in nonpregnant individuals, administration of vaginal progesterone in pregnant individuals only minimally impacts systemic exposure. There is a limited trend of rising serum progesterone over baseline levels, with significant inter-individual variability. Serum progesterone is unlikely to be a good candidate for establishing pharmacokinetics or dosing of vaginal progesterone in pregnancy for preterm birth prevention.

Pharmacokinetics and tolerability of a novel progesterone intravaginal ring in sheep.

The objectives of this work were to evaluate the in vitro release and in vivo pharmacokinetics and local tolerability of a novel, segmented ethylene-vinyl acetate (EVA) intravaginal ring (IVR) delivering progesterone (P) in drug-naïve ovariectomized female Dorset crossbred sheep. Following preparation and assessment of in vitro release of P, animals were randomized into one of six treatment groups: group 1 Crinone® 8% gel (90 mg); group 2 Prometrium® 200-mg capsules; group 3 placebo IVR; group 4 progesterone (P) IVR 4 mg/day; group 5 P IVR 8 mg/day; or group 6 P IVR 12 mg/day. Crinone 8% gel and Prometrium capsules were administered once daily for 28 days. IVRs were inserted vaginally on day 1 and remained in place through day 14; a new ring was administered on day 15 and was removed at day 28. Animals underwent daily examinations to confirm ring placement, and vaginal irritation was scored from 0 (none) to 4 (severe). Blood samples were taken at scheduled times for pharmacokinetic analysis. Postmortem examinations performed on all IVR groups included vaginal irritation, macroscopic, and microscopic evaluations, including irritation scoring and histopathology. Intravaginal rings were retained over 28 days in all animals. Clinical observations showed no significant abnormal findings in any group. Pharmacokinetic analysis in animals showed sustained release of P over from days 0 through 14 of ring use. Irritation scores and microscopic assessments were consistent with the IVRs being well tolerated. These results will guide future human clinical studies to ultimately develop an IVR for use in women for the prevention of preterm birth.

Pharmacokinetics and Tolerability of a Novel 17ß-Estradiol and Progesterone Intravaginal Ring in Sheep.

This study reports the preparation, in vitro release, pharmacokinetics, and local tolerability of novel ethylene-vinyl acetate intravaginal rings (IVRs) delivering 17ß-estradiol (E2) and progesterone (P), in drug-naïve ovariectomized female Dorset crossbred sheep. After preparation and assessment of in vitro release of E2 and P, animals were randomized to treatment groups 1 or 2 (comparator rings releasing 50 or 100 µg/d E2, respectively), groups 3 or 4 (ethylene-vinyl acetate IVRs, 160 µg/d E2 with 4 [160/4 IVR] or 8 mg/d P [160/8 IVR], respectively), or group 5 (160 µg E2 and 10 mg P administered intravenously). IVRs were placed on day 1 and remained in place through day 29. Animals underwent daily examinations to confirm ring placement, and vaginal irritation was scored from 0 (none) to 4 (severe). Blood samples were taken at scheduled times for pharmacokinetic analysis. Postmortem examinations performed on groups 1-4 were macroscopic and microscopic evaluations, including irritation scoring and histopathology. IVRs were retained over 28 days in all but 1 animal (group 4). In all animal groups, clinical observations showed no significant abnormal findings. Pharmacokinetic analysis in the animals showed sustained release of E2 and P over a 28-day period. Irritation scores and microscopic assessments were consistent with foreign object placement. A novel 2-drug IVR delivery system was well tolerated in a sheep model and pharmacokinetic release was as expected over a 28-day release period. These results will guide future human clinical studies.

Radioiodinated progesterone derivative for progesterone receptor targeting with enhanced nucleus uptake via phenylboronic acid conjugation.

A novel 131 I-radiolabeled probe with aromatic boronate motif (131 I-EIPBA) was designed to target progesterone receptor (PR)-positive breast cancer with enhanced nucleus uptake. Acetylene progesterone was conjugated with pegylated phenylboronic acid via click reaction and radiolabeled with 131 I to afford 131 I-EIPBA. Meanwhile, 131 I-EIPB without boronate was prepared as control agent. After determination of the lipophilicity and stability of these tracers, in vitro cell uptake studies and in vivo biodistribution in rats were performed to verify the enhanced nucleus uptake and PR targeting ability of 131 I-EIPBA. 131 I-EIPBA was obtained with moderate radiochemical yield (40.35 ± 3.52%) and high radiochemical purity (>98%). As expected, the high binding affinity (39.58 nM) of 131 I-EIPBA for PR was determined by cell binding assay. The internalization ratio of 131 I-EIPBA was remarkably higher than that of 131 I-EIPB in PR-positive MCF-7 cells. Furthermore, the enhanced nucleus uptake of 131 I-EIPBA (0.59 ± 0.02%) was found to be significantly higher than that of 131 I-EIPB (0.13 ± 0.01%) in MCF-7 cells. A novel 131 I-EIPBA compound was developed for PR targeting with improved cellular nucleus uptake. Furthermore, the introduction of aromatic boronate motif provides a worthwhile strategy for enhancing the nuclear receptor targeting of tracers.

Estradiol and progesterone bioavailability for moderate to severe vasomotor symptom treatment and endometrial protection with the continuous-combined regimen of TX-001HR (oral estradiol and progesterone capsules).

OBJECTIVE: In the REPLENISH trial, women receiving TX-001HR-an oral, softgel capsule, combining 17ß-estradiol (E2) and progesterone (E2 mg/P4 mg 1/100, 0.5/100), had significantly improved vasomotor symptoms, while having their endometrium protected from hyperplasia. The objective here was to describe P4 levels sufficient to counteract the potential endometrial effects of 1 or 0.5 mg oral E2 with TX-001HR. METHODS: In REPLENISH (phase 3; NCT01942668), serum P4, E2, and estrone (E1) levels were characterized in postmenopausal women treated with TX-001HR (E2 mg/P4 mg: 1/100, 0.5/100, [0.5/50, 0.25/50 and placebo not reported here]) at baseline, week 12, and month 12 for P4, and at baseline, weeks 4 and 12, and months 6, 9, and 12 for E2 and E1. In a phase 1 study, pharmacokinetic parameters were assessed after 7 daily doses of oral E2 mg/P4 mg (1/100 and 0.5/100). RESULTS: In REPLENISH (n = 1,835), mean P4 levels were 0.39 to 0.55 ng/mL with 100-mg P4 doses; E2 levels were 42.3 to 45.6 pg/mL and 23.0 to 27.4 pg/mL for the 1-mg and 0.5-mg E2 doses, respectively; E1 levels were 214 to 242 pg/mL and 114 to 129 pg/mL for the 1-mg and 0.5-mg E2 doses. In the phase 1 study (n = 40; day 7), mean Cavg for P4 was 0.66 ng/mL with 100-mg P4 doses; E2 was 38.1 pg/mL and 29.2 pg/mL for 1 mg and 0.5 mg E2, respectively; and E1 was 211 and 106 pg/mL for 1 mg and 0.5 mg E2. All three analytes reached steady state within 7 days; accumulation ratios were 1.36 to 1.94. CONCLUSIONS: P4 levels observed with TX-001HR were similar in the phase 1 and 3 studies, and were associated with no endometrial hyperplasia with either E2 daily dose over 1 year in the REPLENISH phase 3 study, which showed significant improvements in menopausal vasomotor symptoms.

Development of a mucoinert progesterone nanosuspension for safer and more effective prevention of preterm birth.

Preterm birth (PTB) is a significant global problem, but few therapeutic options exist. Vaginal progesterone supplementation has been demonstrated to reduce PTB rates in women with a sonographic short cervix, yet there has been little investigation into the most effective dose or delivery form. Further, vaginal products like progesterone gel often contain excipients that cause local toxicity, irritation, and leakage. Here, we describe the development and characterization of a mucoinert vaginal progesterone nanosuspension formulation for improved drug delivery to the female reproductive tract. We compare the pharmacokinetics and pharmacodynamics to the clinical comparator progesterone gel in pregnant mice and demonstrate increased vaginal absorption and biodistribution via the uterine first-pass effect. Importantly, the unique plasma progesterone double peak observed in humans, reflecting recirculation from the uterus, was also observed in pregnant mice with vaginal dosing. We adapted a mouse model of progesterone withdrawal that was previously believed to be incompatible with testing the efficacy of exogenous progestins, and are first to demonstrate efficacy in preventing preterm birth with vaginal progesterone in this model. Further, improved vaginal progesterone delivery by the nanosuspension led to increased efficacy in PTB prevention. Additionally, we identified histological and transcriptional evidence of cervical and uterine toxicity with a single vaginal administration of the clinical gel that are absent after dosing with the mucoinert nanosuspension formulation. We demonstrate that a progesterone formulation that is designed for improved vaginal progesterone absorption and vaginal biocompatibility could be more effective for PTB prevention.

Intranasal administration of progesterone: A potential efficient route of delivery for cerebroprotection after acute brain injuries.

Progesterone has been shown to be cerebroprotective in different experimental models of brain injuries and neurodegenerative diseases. The preclinical data provided great hope for its use in humans. The failure of Phase 3 clinical trials to demonstrate the cerebroprotective efficiency of progesterone in traumatic brain injury (TBI) patients emphasizes that different aspects of the design of both experimental and clinical studies should be reviewed and refined. One important aspect to consider is to test different routes of delivery of therapeutic agents. Several studies have shown that the intranasal delivery of drugs could be used in different experimental models of central nervous system diseases. In this review, we will summarize the pharmacokinetic characteristics and practical advantages of intranasal delivery of progesterone. A special emphasis will be placed on describing and discussing our recent findings showing that intranasal delivery of progesterone after transient focal cerebral ischemia: 1) improved motor functions; 2) reduced infarct volume, neuronal loss, blood brain barrier disruption; and 3) reduced brain mitochondrial dysfunctions. Our data suggest that intranasal delivery of progesterone is a potential efficient, safe and non-stressful mode of administration that warrants evaluation for cerebroprotection in patients with brain injuries. This article is part of the Special Issue entitled "Novel Treatments for Traumatic Brain Injury".

Effect of Surfactant-Bile Interactions on the Solubility of Hydrophobic Drugs in Biorelevant Dissolution Media.

Biorelevant dissolution media (BDM) methods are commonly employed to investigate the oral absorption of poorly water-soluble drugs. Despite the significant progress in this area, the effect of commonly employed pharmaceutical excipients, such as surfactants, on the solubility of drugs in BDM has not been characterized in detail. The aim of this study is to clarify the impact of surfactant-bile interactions on drug solubility by using a set of 12 surfactants, 3 model hydrophobic drugs (fenofibrate, danazol, and progesterone) and two types of BDM (porcine bile extract and sodium taurodeoxycholate). Drug precipitation and sharp nonlinear decrease in the solubility of all studied drugs is observed when drug-loaded ionic surfactant micelles are introduced in solutions of both BDM, whereas the drugs remain solubilized in the mixtures of nonionic polysorbate surfactants + BDM. One-dimensional and diffusion-ordered 1H NMR spectroscopy show that mixed bile salt + surfactant micelles with low drug solubilization capacity are formed for the ionic surfactants. On the other hand, separate surfactant-rich and bile salt-rich micelles coexist in the nonionic polysorbate surfactant + bile salt mixtures, explaining the better drug solubility in these systems. The nonionic alcohol ethoxylate surfactants show intermediate behavior. The large dependence of the drug solubility on surfactant-bile interactions (in which the drug molecules do not play a major role per se) highlights how the complex interplay between excipients and bile salts can significantly change one of the key parameters which governs the oral absorption of poorly water-soluble drugs, viz. the drug solubility in the intestinal fluids.

Effect on endometrial histology and pharmacokinetics of different dose regimens of progesterone vaginal pessaries, in comparison with progesterone vaginal gel and placebo.

STUDY QUESTION: Which progesterone vaginal pessary dose regimen induces adequate secretory transformation of the endometrium, in comparison with progesterone vaginal gel and placebo? SUMMARY ANSWER: The best secretory transformation of the endometrium was observed during treatment with 400 mg progesterone vaginal pessaries, administered twice daily. WHAT IS KNOWN ALREADY: Vaginally administered progesterone is widely used for luteal phase support (LPS) in assisted reproductive techniques (ART). Although several vaginal formulations using various doses are available, little is known on the impact of formulation and doses at the endometrial level. STUDY DESIGN, SIZE, DURATION: The study had a randomised, observer-blind design and comprised two parts. The participants used study medication during two or three treatment periods, separated by washout periods. Subjects in Part 1 (n = 61 treated) received 200 mg progesterone vaginal pessaries twice daily (bid), 400 mg pessaries bid and the comparator 90 mg progesterone vaginal gel once daily (od) in a 3-way crossover design. Subjects in Part 2 (n = 64 treated) received 100 mg pessaries bid in one period and 400 mg pessaries od in the other period in a 2-way crossover design. A subgroup of these subjects (n = 22 treated) received placebo vaginal pessaries bid in a third period in a non-randomised manner. The study was performed from May 2012 until April 2013. PARTICIPANTS/MATERIALS, SETTING, METHODS: The study was performed at a clinical research centre in healthy female volunteers of reproductive age. The subjects used 2 mg estradiol bid for 24 days in each treatment cycle. Progesterone or placebo was administered vaginally from Day 15 onwards during 10 days. In each treatment period, an endometrial biopsy for histological evaluation was performed on Day 23 and pharmacokinetic parameters were determined after the first progesterone dose on Day 15 and after the last dose on Day 24. MAIN RESULTS AND THE ROLE OF CHANCE: Frequencies of (early and late) secretory transformation of the endometrium, i.e. adequate responses, during treatment with 200 mg and 400 mg vaginal pessaries bid were comparable with those during 90 mg vaginal gel treatment (90-94%), whereas lower secretory transformation rates were observed during treatment with 100 mg bid and 400 mg od (64-75%). At the time of the endometrial biopsy in the cycle the late secretory state of the endometrium, which is characteristic of adequate luteal support, was observed more often with 400 mg pessaries bid (90%) than with vaginal gel (82%) and with lower pessary doses (64-78%). Pharmacokinetic parameters after repeated dosing of vaginal pessaries showed a dose-dependent, but not dose-proportional, increase of plasma progesterone levels. The lowest incidence of bleeding and spotting was reported during treatment with 400 mg pessaries bid. LIMITATIONS REASONS FOR CAUTION: The primary outcome parameter, rate of secretory transformation of the endometrium, is a surrogate for endometrial receptivity and for the actual clinical efficacy. WIDER IMPLICATIONS OF THE FINDINGS: Delivery of progestesterone through 400 mg pessaries bid is an effective alternative method for luteal support in ART. STUDY FUNDING/COMPETING INTEREST(S): The study was funded by Actavis Group PTC ehf., Iceland, part of Teva Pharmaceuticals, and L.D. Collins. I.D. and C.K. are directors of Dinox, a contract research organisation. I.K. is Managing Director of Pharmaplex and M.W. is Managing Director of M.A.R.C.O., service organisations involved in organisation/supervision and evaluation/reporting of clinical trials. All received funding for the conduct of the study from Actavis. S.H. and Th.M. are employees of Actavis. TRIAL REGISTRATION NUMBER: EudraCT number 2012-001726-95.

Administration of progesterone BioRelease LA inhibits follicular growth in llamas (Lama glama) regardless of follicle diameter at the start of treatment.

The aims of the study were twofold: first, the comparison of the pharmacokinetics parameters of two doses of Progesterone BioRelease® LA, (BioRelease Technologies, Lexington, KY, USA) one of 300 mg and other of 150 mg and their effects on ovarian dynamics in llamas. Based on the results from the first study, the aim of the second study was to evaluate the effect of the doses of 150 mg of progesterone on follicular activity considering the stage of the largest follicle at the beginning of treatment. The results in Study 1 showed that both doses of the formulation induced plasma progesterone concentrations higher than 1 ng/ml during the first 6 days of treatment in all females, progesterone concentrations steadily decline until Day 5 following by a slowly decrease. The total amount of progesterone released during treatment was higher in Group 300 than in Group 150 (p = 0.045). Mean maximum concentrations were 14.9 ± 2.24 and 14.3 ± 2.16 ng/ml for Group A versus Group B (p = 0.58), and they were registered on Day 1.5 ± 0.22 and 1.7 ± 0.34 days, respectively (p = 0.10). None of the animals of Group A showed progesterone concentration below 1 ng/ml during all studied period. The treatment applied in Study 2 was efficient in inhibiting the ovarian follicular dynamics and to start a superestimulatory treatment. The use of progesterone Biorelease® LA of 150 mg in comparison with the dose of 300 mg could be more effective in the use of synchronization protocols in llamas for AI or prior to the application of an ovarian superstimulatory treatment.

Preparation of TPP-crosslinked chitosan microparticles by spray drying for the controlled delivery of progesterone intended for estrus synchronization in cattle.

PURPOSE: Planned reproduction in cattle involves regulation of estrous cycle and the use of artificial insemination. Cycle control includes the administration of exogenous progesterone during 5-8 days in a controlled manner allowing females to synchronize their ovulation. Several progesterone delivery systems are commercially available but they have several drawbacks. The aim of the present contribution was to evaluate chitosan microparticles entrapping progesterone as an alternative system. METHODS: Microparticles were prepared by spray drying. The effect of formulation parameters and experimental conditions on particle features and delivery was studied. A mathematical model to predict progesterone plasma concentration in animals was developed and validated with experimental data. RESULTS: Microparticle size was not affected by formulation parameters but sphericity enhances as Tween 80 content increases and it impairs as TPP content rises. Z potential decreases as phosphate content rises. Particles remain stable in acidic solution but the addition of surfactant is required to stabilize dispersions in neutral medium. Encapsulation efficiencies was 69-75%. In vitro delivery studies showed burst and diffusion-controlled phases, being progesterone released faster at low pH. In addition, delivery extend in cows was affected mainly by particle size and hormone initial content, while the amount injected altered plasma concentration. Theoretical predictions with excellent accuracy were obtained. CONCLUSION: The mathematical model developed can help to find proper particle features to reach specific delivery rates in the animals. This not only save time, money and effort but also minimized experimentation with animals which is desired from an ethical point of view.