In Vitro and In Vivo Evaluations of Dihydroquinoline- and Dihydroisoquinoline-based Targetor Moieties for Brain-specific Chemical Delivery Systems

Brain-targeted delivery of various drugs can be successfully achieved by chemical delivery systems (CDS) that contain a 1,4-dihydropyridine-based redox targetor moiety and undergo a sequential metabolism. However, the susceptibility of this moiety toward hydration in acidic media may limit the shelf-life of such compounds in aqueous formulation. Here, a systematic investigation of the chemical stability toward oxidation and hydration of ester and amide derivatives of 3-substituted 1,4-dihydropyridine, 1,4-dihydroquinoline, and 4-substituted 1,2-dihydroisoquinoline is reported, together with the in vitro stability and in vivo (rat) distribution of isoquinoline-based testosterone and hydrocortisone chemical delivery systems, which were selected as having the most suitable acid-resistant targetor moieties.     

Soft Drugs 18. Oral and Rectal Delivery of Loteprednol Etabonate,a Novel Soft Corticosteroid,in Rats—for Safer Treatment of Gastrointestinal Inflammation

Purpose. As a safe anti-inflammatory corticosteroid, the utility of loteprednol etabonate (LE) for the treatment of gastrointestinal inflammation, via oral and rectal administration, was investigated in rats. Methods. In vivo, LE solution and suspension were orally administered (20 mg/kg), and various LE preparations (solution, suspension & suppository) were applied in rectal loops (0.2 mg per loop). In vitro, various GI tissues were used to study the stability and partition of LE. Results. After oral administration of LE solution, LE reached the upper GI tract effectively, but not the colon, due to absorption and/or decomposition. In suspension, LE reached most of the GI tract (except rectum) in 8 hr and showed little absorption. After rectal applications, LE remained intact in the rectal loop for more than five hours with a slow rate of disappearance, however, LE distributed in the rectal membrane to some extent. The concentrations of LE and its inactive metabolites in plasma after both oral and rectal administrations were lower than the detection limit (0.1 µg/ml) at anytime during the experiments. In vitro, LE in solution was stable in stomach, but not in cecum, due to the hydrolysis by the cecal resident micro flora. In solution, LE distributed into the mucosal membranes efficiently (about 2.5 ~ 4.0 µg/g tissue). Conclusions. The results suggest that LE can be orally or rectally delivered in the GI tract for the topical treatment of the inflammatory bowel disease.     

A project to improve nasal ice packs

Nasal problems are a commonly encountered diseases in the ENT (ear, nose, and throat) specialty. People with nasal problems usually seek medical therapy. When the problem cannot resolved by medical therapy then surgery becomes an option. According to statistics of the ENT unit where author served in 2006, 255 patients underwent nasal surgery. Swelling and pain are the most common discomfort symptoms for patients after nasal surgery. After data collection, it was found that only 16.7% of patients were willing to use ice packs, because they attached poorly (100%), were difficult to secure (100%), and were inconvenient to use (83.3%). After seeking an alternative ice pack replacement, the group decided to use a latex glove filled with 50 gm crushed ice and water in its index and middle fingers, tied with shoe laces and tied to the ears. The project involved three periods: preparation, execution, and evaluation. The results showed that 96.7% of patients were willing to use the new ice pack. The satisfaction rate for use of the new ice pack was 96.7%. The results of this project might improve patients' quality of care, as well as cost reduction.     

Overexpression of adenovirus E3-11.6K protein induces cell killing by both caspase-dependent and caspase-independent mechanisms

Recent studies have shown enhanced antitumor efficacy with adenoviruses that either lack E1B-19K or overexpress E3-11.6K (also known as adenoviral death protein). E1B-19K is a well-characterized anti-apoptotic protein, and viruses with E1B-19K deletions show increased cytopathicity. However, the mechanism of cell killing by E3-11.6K, which plays an important role in killing infected cells and virion release, is not well characterized. To understand the mechanism of cell killing following E3-11.6K overexpression, we constructed a recombinant adenovirus, Ad-ME, by introducing viral major late promoter upstream of the E3-11.6K sequence. Similar to the E1B-19K-deleted virus, E1B/19K-, Ad-ME induced cell death to a greater extent than the wild-type virus. Cell shrinkage, membrane blebbing, activation of caspases 3 and 9, cleavage of poly(ADP-ribose)polymerase (PARP), DNA degradation, and ratio of ADP to ATP in Ad-ME-infected cells indicated that apoptosis contributes to cell death following E3-11.6K overexpression. However, the levels of activation of caspases 3 and 9 were lower in cells infected with Ad-ME compared to those infected with E1B/19K-. Furthermore, cell killing by Ad-ME was not effectively inhibited by Z-VAD-FMK, a general caspase inhibitor. Taken together, our results suggest both caspase-dependent and caspase-independent mechanisms of cell killing due to overexpression of E3-11.6K.     

Soft Drugs. XX. Design,Synthesis, and Evaluation of Ultra-Short Acting Beta-Blockers

A new type of ultra-short acting -blocker which might prove advantageous in treating acute arrhythmias was designed, synthesized and investigated. Based on the soft drug inactive metabolite approach, the inactive phenylacetic acid metabolite of both metoprolol and atenolol was reactivated by esterification with sulfur-containing aliphatic alcohols. Since the sulfur-containing moieties are labile to the ubiquitous esterases, the new compounds should be inactivated by a one step enzymatic cleavage back to the inactive phenylacetic acid derivative. Pharmacological and pharmacokinetic profiles of the new compounds were evaluated in rats and rabbits. Isoproterenol-induced tachycardia was inhibited with short-term infusion of each compound. This tachycardia blocking effect rapidly disappeared upon termination of infusion, while -blocking activity was 2–4-fold longer after comparable doses of the short-acting -blocker, esmolol. The rapid recovery from the -receptor blockade is believed due to fast hydrolysis of the soft drugs in the body. This is supported from in vitro results showing the t_l/2 of esmolol is about 10-fold longer than the new soft drugs in rat, rabbit, dog and human blood. Hydrolysis studies in phosphate buffered solutions indicated that the esters are labile to base-catalyzed hydrolysis. However, the relative t_1/2 values measured in biological media compared to phosphate buffered solution clearly support rapid enzymatic cleavage of the soft drugs. Interestingly, one of the soft -blockers, the sulfonyl ester derivative, showed a unique property of exhibiting good -receptor blocking activity without significant hypotensive action.     

Pharmacokinetics of the sequential metabolites of loteprednol etabonate in rats

Pharmacokinetics, metabolism and excretion of two sequential inactive metabolites of the soft corticosteroid loteprednol etabonate (LE), Delta1-cortienic acid etabonate (AE) and Delta1-cortienic acid (A), have been investigated in rats. Pharmacokinetic studies (two-compartment model, 10 mg kg(-1) intra-venous bolus of AE or A) found the elimination of both AE (t(1/2)(beta), 12.46 +/- 1.18 min; CL total, 101.94 +/- 5.80 mL min(-1) kg(-1); and K el, 0.24 +/- 0.02 min(-1)) and A (t(1/2)(beta), 14.62 +/- 0.46 min; CL total, 53.80 +/- 1.40 mL min(-1) kg(-1); and K el, 0.18 +/- 0.02 min(-1)) to be significantly faster than that previously determined for the parent LE (t(1/2)(beta), 43.41 +/- 7.58 min; CL total, 67.40 +/- 11.60 mL min(-1) kg(-1); and K el, 0.071 +/- 0.024 min(-1)). For metabolism and excretion evaluations, 1 and 10 mg kg(-1) of either AE or A were intravenously administered, and the urine and bile were collected. AE and A rapidly reached their peak concentrations in the bile and urine, and most of them were eliminated within one hour. Total cumulative excretions at 4 h after 1 and 10 mg kg(-1) injections were 85.51 +/- 3.38% and 67.50 +/- 2.67% for AE, and 71.90 +/- 3.72% and 37.73 +/- 2.69% for A in bile; and 4.84 +/- 1.87% and 13.85 +/- 3.27% for AE, and 24.28 +/- 8.44% and 22.35 +/- 1.12% for A in urine, respectively. After AE administration, the excretion of AE was > 90%, and A was < 10% in all cases, indicating that the elimination of AE was much faster than its metabolism (to A). In a manner similar to that seen for LE, dose-dependent elimination was observed both in AE and A. These results suggested that both AE and A were ideal leads for the design of soft steroids based on the inactive metabolite approach.     

Synthesis and biological evaluations of brain-targeted chemical delivery systems of [Nva2]-TRH

Various chemical delivery systems for [Nva2]-TRH were synthesized and their CNS activity was investigated and compared with that of a similar chemical delivery system of [Leu2]-TRH, previously studied. Sequential metabolism of the chemical delivery system delivered to the brain, starting with the conversion of the dihydrotrigonellyl (DHT) to the trigonellyl (T+) moiety, will provide the lock-in to the brain of the T+-chemical delivery system, which will undergo hydrolysis of the cholesteryl ester, formation of the Pr-amide and cleavage of the spacer-T+ part, allowing ultimately the sustained release of the active [Nva2]-TRH. The CNS activity was assessed by measuring the extent of antagonizing barbiturate-induced sleeping time in mice. The fully packaged DHT-Pro-Pro-Gln-Nva-Pro-Gly-OCh produced robust antagonism, reducing sleeping time from 89 min to 48 min, similar to the Leu2-analogue (49 min). However, the partially substituted [Nva2]-TRH analogues showed little or no CNS activity. The results indicate that the fully packaged delivery system is necessary to produce the successful brain targeting of the precursor construct and effective release of the Gln-Nva-ProNH2.     

Using a short questionnaire of the perimenopausal fatigue scale to evaluate perimenopausal women prone to fatigue syndrome

ObjectiveFatigue, a painful and unpleasant subjective experience, is common in perimenopausal women. Therefore, an effective tool to evaluate the fatigue-precipitating factor is important for perimenopausal women prone to fatigue syndrome.Materials and methodsThis study was surveyed by short-term perimenopausal fatigue scale. The enrollment period was from November 2019 to January 2020. The subjects were perimenopausal women prone to perimenopausal fatigue. The differences between the fatigue-precipitating factors and the degrees of fatigue and disturbance were determined by one-way ANOVA and t test.ResultsA total of 220 perimenopausal women with mean age of 51.3 years were included. Among these, 64.1% did not have a habit of regular exercise and 55.5% had chronic diseases. Fatigue syndrome was found in 64.1% of subjects, who were mainly presented by shoulder and neck pain and sleep problems. There were significant differences between “perimenopausal fatigue” and “duration” (p < 0.001); “with and without regular exercise” (p = 0.05); and “with and without chronic diseases” (p = 0.03).ConclusionsOur study showed the perimenopausal fatigue syndrome is more frequently found in perimenopausal women who have a co-morbidity (chronic illness) and do not have a habit of regular exercise. An early identification and prompt intervention may help perimenopausal women to deal with their fatigue syndrome. The short questionnaire perimenopausal fatigue scale seems to be useful for screening perimenopausal women prone to fatigue syndrome.     

In vitro and in vivo evaluations of dihydroquinoline- and dihydroisoquinoline-based targetor moieties for brain-specific chemical delivery systems

Brain-targeted delivery of various drugs can be successfully achieved by chemical delivery systems (CDS) that contain a 1,4-dihydropyridine-based redox targetor moiety and undergo a sequential metabolism. However, the susceptibility of this moiety toward hydration in acidic media may limit the shelf-life of such compounds in aqueous formulation. Here, a systematic investigation of the chemical stability toward oxidation and hydration of ester and amide derivatives of 3-substituted 1,4-dihydropyridine, 1,4-dihydroquinoline, and 4-substituted 1,2-dihydroisoquinoline is reported, together with the in vitro stability and in vivo (rat) distribution of isoquinoline-based testosterone and hydrocortisone chemical delivery systems, which were selected as having the most suitable acid-resistant targetor moieties.     

Design,Pharmacokinetic, and Pharmacodynamic Evaluation of a New Class of Soft Anticholinergics

Purpose. To design and evaluate a new class of soft anticholinergics with subtype selectivity. Methods. A new class of soft anticholinergics was designed based on the inactive metabolite approach. Four compounds were synthesized. The potency and soft nature of the compounds were evaluated by receptor binding, cardiac, and mydriatic studies. Stability and pharmacokinetic studies were also performed on these newly synthesized soft anticholinergics. Results. Receptor binding studies of the soft anticholinergics on cloned muscarinic receptors indicated pKi values in the range of 7.5 to 8.9. Two compounds, 9a and 13a, of the series showed muscarinic subtype receptor selectivity (M₃/M₂). In mydriatic studies, 13a and 13b showed shorter duration of action in the treated eyes than tropicamide. In the control eyes, significant dilation of pupils was found only in rabbits treated with atropine and tropicamide, indicating that the soft anticholinergics lack systemic effects because of their facile hydrolytic deactivation. Consistent with their soft nature, this new class of soft anticholinergics displayed much shorter cardiovascular effects in the carbachol-induced bradycardia (10 to 15 min) in rats than atropine (> 60 min). Stability and pharmacokinetic studies suggested that the new soft anticholinergics were rapidly eliminated from plasma (systemic circulation) after i.v. administration. Conclusions. A new class of anticholinergics was designed and synthesized, and the PK/PD evaluation confirmed they were potent soft anticholinergics; two of them showed muscarinic receptor subtype selectivity (M₃/M₂).