Enhancing Smoking Risk Communications: The Influence of Health Literacy and Message Content

Background

Efforts are needed to ensure that smokers with lower health literacy are provided with understandable and impactful information about the health consequences of smoking and benefits of quitting.

Purpose

To test the influence of health literacy on smokers' responses to health risk messages manipulated on framing (gain vs. loss) and emotionality (factual vs. emotional).

Methods

Participants (N = 402) were randomized to evaluate one of four sets of smoking risk messages (factual gain-framed, factual loss-framed, emotional gain-framed, or emotional loss-framed). Multiple linear regressions examined main effects of health literacy, message emotionality, and message framing on: (a) risk perceptions, (b) behavioral expectations (i.e. cut down, limit, quit), and (c) risk knowledge. Two-way interactions of health literacy with emotionality and framing were examined for these outcomes. Analyses were based on theory-driven, a priori hypotheses.

Results

As hypothesized, main effects emerged such that smokers with higher health literacy reported stronger risk perceptions and knowledge retention regardless of message type. Additionally, emotional (vs. factual) and gain- (vs. loss-) framed messages were associated with certain lower risk perceptions regardless of health literacy level. Consistent with hypotheses, two-way crossover interactions emerged between health literacy and emotionality. Among smokers with higher health literacy, factual messages produced higher perceived risk and stronger expectations for quitting. Among smokers with lower health literacy, emotional messages produced higher perceived risk and stronger expectations for quitting.

Conclusions

Health literacy plays an important role in influencing how smokers respond to different risk messages. One's health literacy should be considered when determining whether risk communications emphasize factual or emotional content.

HIV Care Initiation: A Teachable Moment for Smoking Cessation?

Introduction

Tobacco use among persons living with HIV represents an important risk factor for poor treatment outcomes, morbidity, and mortality. Thus, efforts designed to inform the development of appropriate smoking cessation programs for this population remains a public health priority. To address this need, a study was conducted to longitudinally assess the relationship between intention to quit smoking and cessation over the 12-month period following initiation of HIV care.

Methods

Patients initiating HIV care at a large inner city safety net clinic were enrolled (n = 378) in a 12-month prospective study. Audio computer-assisted self-interviews were conducted at baseline, and at 3, 6, 9, and 12 months post-enrollment, and HIV-related clinical data were collected from participants' electronic medical records. Variables of interest included intention to quit smoking, 7-day point prevalence smoking abstinence (biochemically verified), and stage of HIV. Data were collected in Houston, Texas from 2009 to 2015.

Results

The sample was 75% male and 62% Black. Findings indicated that intention to quit smoking increased between baseline and 3 months, and subsequently trended downward from 3 to 12 months. Results from linear and generalized linear mixed models indicated that participants with advanced HIV disease (vs. not advanced) reported significantly (p < .05) higher intention to quit smoking at 3, 6, and 12 months post-study enrollment. A similar though nonsignificant pattern was observed in the smoking abstinence outcome.

Conclusions

HIV treatment initiation appears to be associated with increases in intention to quit smoking thus serves as a potential teachable moment for smoking cessation intervention.

Implications

This study documents significant increases in intention to quit smoking in the 3-month period following HIV care initiation. Moreover, quit intention trended downward following the 3-month follow-up until the 12-month follow-up. In addition, a marked effect for HIV disease stage was observed, whereby participants with advanced HIV disease (vs. those without) experienced a greater increase in intention to quit. HIV treatment initiation appears to be associated with increases in intention to quit smoking, thus serves as a crucial teachable moment for smoking cessation intervention for people living with HIV.

Understanding the link between contingency management and smoking cessation: The roles of sex and self-efficacy

INTRODUCTION

Little is known about the mechanisms linking contingency management (CM) treatment with smoking cessation, and recent research suggests that the CM approach is associated with better smoking cessation outcomes among females than males. The current study investigated self-efficacy as a potential mechanism through which CM treatment influences smoking cessation, and explored whether these relationships differed by sex.

METHODS

Participants (N = 139) were primarily Black (63.3%) and female (57.6%) adults enrolled in a safety-net hospital smoking cessation program. Participants received usual care (UC), which included pharmacotherapy and counseling sessions (n = 66) or a CM intervention (UC + 4 weeks of small, abstinence contingent financial incentives; n = 73). Self-efficacy for quitting was measured on the day after quitting with the Self-Efficacy Scale/Confidence (SESC) questionnaire. Mediation analyses were conducted to evaluate the indirect effects of treatment group on biochemically-verified abstinence (4-weeks post-quit) via self-efficacy, and moderated mediation analyses were conducted to evaluate the moderating role of sex.

RESULTS

Self-efficacy was not found to mediate the relations between CM treatment and smoking cessation in the overall sample. However, analyses indicated a significant moderating effect of sex on the indirect effect of treatment group on smoking cessation through self-efficacy (each of the 3 SESC subscales). Specifically, there was a stronger association between CM and greater self-efficacy among females than males.

CONCLUSION

Findings suggest that CM treatment had a differing impact on self-efficacy among males and females, which in turn influenced the likelihood of smoking cessation.

Cost-effectiveness analysis of smoking cessation interventions using cell phones in a low-income population

BACKGROUND

The prevalence of cigarette smoking is significantly higher among those living at or below the federal poverty level. Cell phone-based interventions among such populations have the potential to reduce smoking rates and be cost-effective.

METHODS

We performed a cost-effectiveness analysis of three smoking cessation interventions: Standard Care (SC) (brief advice to quit, nicotine replacement therapy and self-help written materials), Enhanced Care (EC) (SC plus cell phone-delivered messaging) and Intensive Care (IC) (EC plus cell phone-delivered counselling). Quit rates were obtained from Project ACTION (Adult smoking Cessation Treatment through Innovative Outreach to Neighborhoods). We evaluated shorter-term outcomes of cost per quit and long-term outcomes using cost per quality-adjusted life year (QALY).

RESULTS

For men, EC cost an additional $541 per quit vs SC; however, IC cost an additional $5232 per quit vs EC. For women, EC was weakly dominated by IC-IC cost an additional $1092 per quit vs SC. Similarly, for men, EC had incremental cost-effectiveness ratio (ICER) of $426 per QALY gained vs SC; however, IC resulted in ICER of $4127 per QALY gained vs EC. For women, EC was weakly dominated; the ICER of IC vs SC was $1251 per QALY gained. The ICER was below maximum acceptable willingness-to-pay threshold of $50 000 per QALY under all alternative modelling assumptions.

DISCUSSION

Cell phone interventions for low socioeconomic groups are a cost-effective use of healthcare resources. Intensive Care was the most cost-effective strategy both for men and women.

TRIAL REGISTRATION NUMBER

NCT00948129; Results.

An ecological momentary intervention for smoking cessation: The associations of just-in-time, tailored messages with lapse risk factors

BACKGROUND

Smartphone apps can provide real-time, tailored interventions for smoking cessation. The current study examines the effectiveness of a smartphone-based smoking cessation application that assessed risk for imminent smoking lapse multiple times per day and provided messages tailored to current smoking lapse risk and specific lapse triggers.

METHODS

Participants (N=59) recruited from a safety-net hospital smoking cessation clinic completed phone-based ecological momentary assessments (EMAs) 5 times/day for 3 consecutive weeks (1week pre-quit, 2weeks post-quit). Risk for smoking lapse was estimated in real-time using a novel weighted lapse risk estimator. With each EMA, participants received messages tailored to current level of risk for imminent smoking lapse and self-reported presence of smoking urge, stress, cigarette availability, and motivation to quit. Generalized linear mixed model analyses determined whether messages tailored to specific lapse risk factors were associated with greater reductions in these triggers than messages not tailored to specific triggers.

RESULTS

Overall, messages tailored to smoking urge, cigarette availability, or stress corresponded with greater reductions in those triggers than messages that were not tailored to specific triggers (p's=0.02 to <0.001). Although messages tailored to stress were associated with greater reductions in stress than messages not tailored to stress, the association was non-significant (p=0.892) when only moments of high stress were included in the analysis.

CONCLUSIONS

Mobile technology can be used to conduct real-time smoking lapse risk assessment and provide tailored treatment content. Findings provide initial evidence that tailored content may impact users' urge to smoke, stress, and cigarette availability.

Financial strain indirectly influences smoking cessation through withdrawal symptom severity

BACKGROUND

Financial strain has an adverse impact on smoking cessation. However, the mechanisms through which financial strain influences cessation remain unclear. The purpose of the current study was to determine whether financial strain indirectly influenced smoking cessation through withdrawal symptom severity.

METHODS

Participants (N=139) were primarily Black (63.3%) and female (57.6%) adults enrolled in a smoking cessation program at a safety-net hospital. A self-report financial strain questionnaire was completed one week prior to the scheduled quit date, and the Wisconsin Smoking Withdrawal Scale (WSWS) was completed on the day after the scheduled quit date. Biochemically-verified 7-day point prevalence abstinence was assessed four weeks after the scheduled quit date. Adjusted mediation analyses were conducted using the PROCESS macro for SPSS to evaluate the indirect effects of financial strain on smoking cessation via post-quit withdrawal symptom severity.

RESULTS

Analyses indicated a significant indirect effect of financial strain on smoking cessation through total withdrawal symptom severity, B=0.027; 95% CI (0.003, 0.066); and specifically anger, B=0.035; 95% CI (0.008, 0.074), anxiety, B=0.021; 95% CI (0.001, 0.051), and sleep symptoms, B=0.015; 95% CI (0.005, 0.043). Greater pre-quit financial strain was associated with greater post-quit withdrawal symptom severity, which increased the likelihood of non-abstinence 4 weeks after the scheduled quit attempt. The direct effect of financial strain on smoking cessation was not significant in any of the mediation models.

CONCLUSIONS

Findings: suggest that withdrawal severity is an underlying mechanism through which financial strain influences smoking cessation.

An Ecological Momentary Intervention for Smoking Cessation: Evaluation of Feasibility and Effectiveness

BACKGROUND

Despite substantial public health progress in reducing the prevalence of smoking in the United States overall, smoking among socioeconomically disadvantaged adults remains high.

OBJECTIVE

To determine the feasibility and preliminary effectiveness of a novel smartphone-based smoking cessation app designed for socioeconomically disadvantaged smokers.

METHODS

Participants were recruited from a safety-net hospital smoking cessation clinic in Dallas, Texas, and were followed for 13 weeks. All participants received standard smoking cessation clinic care (ie, group counseling and cessation pharmacotherapy) and a smartphone with a novel smoking cessation app (ie, Smart-T). The Smart-T app prompted 5 daily ecological momentary assessments (EMAs) for 3 weeks (ie, 1 week before cessation and 2 weeks after cessation). During the precessation period, EMAs were followed by messages that focused on planning and preparing for the quit attempt. During the postcessation period, participant responses to EMAs drove an algorithm that tailored messages to the current level of smoking lapse risk and currently present lapse triggers (eg, urge to smoke, stress). Smart-T offered additional intervention features on demand (eg, one-click access to the tobacco cessation quitline; "Quit Tips" on coping with urges to smoke, mood, and stress).

RESULTS

Participants (N=59) were 52.0 (SD 7.0) years old, 54% (32/59) female, and 53% (31/59) African American, and 70% (40/57) had annual household income less than US $16,000. Participants smoked 20.3 (SD 11.6) cigarettes per day and had been smoking for 31.6 (SD 10.9) years. Twelve weeks after the scheduled quit date, 20% (12/59) of all participants were biochemically confirmed abstinent. Participants responded to 87% of all prompted EMAs and received approximately 102 treatment messages over the 3-week EMA period. Most participants (83%, 49/59) used the on-demand app features. Individuals with greater nicotine dependence and minority race used the Quit Tips feature more than their counterparts. Greater use of the Quit Tips feature was linked to nonabstinence at the 2 (P=.02), 4 (P<.01), and 12 (P=.03) week follow-up visits. Most participants reported that they actually used or implemented the tailored app-generated messages and suggestions (83%, 49/59); the app-generated messages were helpful (97%, 57/59); they would like to use the app in the future if they were to lapse (97%, 57/59); and they would like to refer friends who smoke to use the Smart-T app (85%, 50/59). A minority of participants (15%, 9/59) reported that the number of daily assessments (ie, 5) was "too high."

CONCLUSIONS

This novel just-in-time adaptive intervention delivered an intensive intervention (ie, 102 messages over a 3-week period), was well-liked, and was perceived as helpful and useful by socioeconomically disadvantaged adults who were seeking smoking cessation treatment. Smartphone apps may be used to increase treatment exposure and may ultimately reduce tobacco-related health disparities among socioeconomically disadvantaged adults.

Using Intensive Longitudinal Data Collected via Mobile Phone to Detect Imminent Lapse in Smokers Undergoing a Scheduled Quit Attempt

Background

Mobile phone‒based real-time ecological momentary assessments (EMAs) have been used to record health risk behaviors, and antecedents to those behaviors, as they occur in near real time.

Objective

The objective of this study was to determine if intensive longitudinal data, collected via mobile phone, could be used to identify imminent risk for smoking lapse among socioeconomically disadvantaged smokers seeking smoking cessation treatment.

Methods

Participants were recruited into a randomized controlled smoking cessation trial at an urban safety-net hospital tobacco cessation clinic. All participants completed in-person EMAs on mobile phones provided by the study. The presence of six commonly cited lapse risk variables (ie, urge to smoke, stress, recent alcohol consumption, interaction with someone smoking, cessation motivation, and cigarette availability) collected during 2152 prompted or self-initiated postcessation EMAs was examined to determine whether the number of lapse risk factors was greater when lapse was imminent (ie, within 4 hours) than when lapse was not imminent. Various strategies were used to weight variables in efforts to improve the predictive utility of the lapse risk estimator.

Results

Participants (N=92) were mostly female (52/92, 57%), minority (65/92, 71%), 51.9 (SD 7.4) years old, and smoked 18.0 (SD 8.5) cigarettes per day. EMA data indicated significantly higher urges (P=.01), stress (P=.002), alcohol consumption (P<.001), interaction with someone smoking (P<.001), and lower cessation motivation (P=.03) within 4 hours of the first lapse compared with EMAs collected when lapse was not imminent. Further, the total number of lapse risk factors present within 4 hours of lapse (mean 2.43, SD 1.37) was significantly higher than the number of lapse risk factors present during periods when lapse was not imminent (mean 1.35, SD 1.04), P<.001. Overall, 62% (32/52) of all participants who lapsed completed at least one EMA wherein they reported ≥3 lapse risk factors within 4 hours of their first lapse. Differentially weighting lapse risk variables resulted in an improved risk estimator (weighted area=0.76 vs unweighted area=0.72, P<.004). Specifically, 80% (42/52) of all participants who lapsed had at least one EMA with a lapse risk score above the cut-off within 4 hours of their first lapse.

Conclusions

Real-time estimation of smoking lapse risk is feasible and may pave the way for development of mobile phone‒based smoking cessation treatments that automatically tailor treatment content in real time based on presence of specific lapse triggers. Interventions that identify risk for lapse and automatically deliver tailored messages or other treatment components in real time could offer effective, low cost, and highly disseminable treatments to individuals who do not have access to other more standard cessation treatments.

Have combustible cigarettes met their match? The nicotine delivery profiles and harmful constituent exposures of second-generation and third-generation electronic cigarette users

INTRODUCTION

Electronic cigarettes' (e-cigarettes) viability as a public health strategy to end smoking will likely be determined by their ability to mimic the pharmacokinetic profile of a cigarette while also exposing users to significantly lower levels of harmful/potentially harmful constituents (HPHCs). The present study examined the nicotine delivery profile of third- (G3) versus second-generation (G2) e-cigarette devices and their users' exposure to nicotine and select HPHCs compared with cigarette smokers.

METHODS

30 participants (10 smokers, 9 G2 and 11 G3 users) completed baseline questionnaires and provided exhaled carbon monoxide (eCO), saliva and urine samples. Following a 12-hour nicotine abstinence, G2 and G3 users completed a 2-hour vaping session (ie, 5 min, 10-puff bout followed by ad libitum puffing for 115 min). Blood samples, subjective effects, device characteristics and e-liquid consumption were assessed.

RESULTS

Smokers, G2 and G3 users had similar baseline levels of cotinine, but smokers had 4 and 7 times higher levels of eCO (p<0.0001) and total 4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanol (i.e., NNAL, p<0.01), respectively, than G2 or G3 users. Compared with G2s, G3 devices delivered significantly higher power to the atomiser, but G3 users vaped e-cigarette liquids with significantly lower nicotine concentrations. During the vaping session, G3 users achieved significantly higher plasma nicotine concentrations than G2 users following the first 10 puffs (17.5 vs 7.3 ng/mL, respectively) and at 25 and 40 min of ad libitum use. G3 users consumed significantly more e-liquid than G2 users. Vaping urges/withdrawal were reduced following 10 puffs, with no significant differences between device groups.

DISCUSSION

Under normal use conditions, both G2 and G3 devices deliver cigarette-like amounts of nicotine, but G3 devices matched the amount and speed of nicotine delivery of a conventional cigarette. Compared with cigarettes, G2 and G3 e-cigarettes resulted in significantly lower levels of exposure to a potent lung carcinogen and cardiovascular toxicant. These findings have significant implications for understanding the addiction potential of these devices and their viability/suitability as aids to smoking cessation.

Polymorphisms in the Hsp70 gene locus are genetically associated with systemic lupus erythematosus

BACKGROUND

Heat shock proteins (Hsps) play a role in the delivery and presentation of antigenic peptides and are thought to be involved in the pathogenesis of multifactorial diseases.

OBJECTIVE

To investigate genes encoding cytosolic Hsp70 proteins for associations of allelic variants with systemic lupus erythematosus (SLE).

METHODS

Case-control studies of two independent Caucasian SLE cohorts were performed. In a haplotype-tagging single-nucleotide polymorphism approach, common variants of HspA1L, HspA1A and HspA1B were genotyped and principal component analyses were performed for the cohort from the Oklahoma Medical Research Foundation (OMRF). Relative quantification of mRNA was carried out for each Hsp70 gene in healthy controls. Conditional regression analysis was performed to determine if allelic variants in Hsp70 act independently of HLA-DR3.

RESULTS

On analysis of common genetic variants of HspA1L, HspA1A and HspA1B, a haplotype significantly associated with SLE in the Erlangen-SLE cohort was identified, which was confirmed in the OMRF cohort. Depending on the cohorts, OR ranging from 1.43 to 1.88 and 2.64 to 3.16 was observed for individuals heterozygous and homozygous for the associated haplotype, respectively. Patients carrying the risk haplotype or the risk allele more often displayed autoantibodies to Ro and La in both cohorts. In healthy controls bearing this haplotype, the amount of HspA1A mRNA was significantly increased, whereas total Hsp70 protein concentration was not altered.

CONCLUSIONS

Allelic variants of the Hsp70 genes are significantly associated with SLE in Caucasians, independently of HLA-DR3, and correlate with the presence of autoantibodies to Ro and La. Hence, the Hsp70 gene locus appears to be involved in SLE pathogenesis.

Evaluation of the genetic association of the PTPN22 R620W polymorphism in familial and sporadic systemic lupus erythematosus

OBJECTIVE

The R620W (1858C-->T) polymorphism in PTPN22 has been implicated in type 1 diabetes mellitus, rheumatoid arthritis, Graves' disease, Hashimoto thyroiditis, autoimmune thyroid disease, and systemic lupus erythematosus (SLE). The aim of this study was to evaluate this polymorphism in patients with familial SLE and in those with sporadic SLE.

METHODS

A total of 4,981 DNA samples were genotyped (from 1,680 SLE patients, 1,834 family members, and 1,467 controls). Both population-based case-control and family-based association designs were used for the analyses.

RESULTS

In the European American familial SLE cohort, the minor 1858T allele was more common in randomly selected patients compared with controls (chi2= 5.61, P = 0.018, odds ratio [OR] 1.46, 95% confidence interval [95% CI] 1.07-1.99). The heterozygous C/T genotype was also more common in these European American patients compared with controls (OR 1.63, 95% CI 1.15-2.30). Family-based association tests showed preferential transmission of the 1858T allele to affected offspring (chi2 = 5.87, P = 0.015). In contrast, the frequency of the 1858T minor allele was not significantly increased in the European American patients with sporadic SLE compared with controls, nor did these patients have preferential transmission of the 1858T allele. Indeed, the difference in the 1858T allele frequency between patients with familial SLE and those with sporadic SLE was measurable (allelic chi2= 4.22, P = 0.04, OR 1.51, 95% CI 1.02-2.24). Our data also showed that among patients with SLE, the 1858T allele was separately associated with type 1 diabetes mellitus and with autoimmune thyroid disease, confirming the findings of other investigators.

CONCLUSION

The 1858T allele of PTPN22 is associated with familial SLE but not with sporadic SLE in European Americans, thereby potentially explaining previous contradictory reports.

Ocular toxicity of vitreal pluronic polyol F-127

To evaluate pluronic polyol F-127 (PF-127) as a vitreous substitute and an intraocular drug delivery system, a total vitrectomy was performed on 18 New Zealand rabbits (18 eyes). The vitreous was replaced with either PF-127 (9 eyes) or balanced salt solution (9 eyes). There was little difference clinically between the eyes containing PF-127 and the control eyes. Both groups showed mild postoperative inflammation, with no differences in intraocular pressures. Histopathologic findings for the control group showed no significant retinal alteration, and serial ERG findings were within normal limits. In contrast, the eyes containing PF-127 showed marked destruction of the retina by 2 weeks after surgery. The ERG amplitudes decreased dramatically to a flat tracing by 24 hours after surgery. Although it is attractive as a potential vitreous substitute, PF-127 is not safe for human use, at least at the concentration used.

Drug release studies on an oil-water emulsion based on a eutectic mixture of lidocaine and prilocaine as the dispersed phase

The in vitro drug release properties of a topical anesthetic formulation known to be effective on intact skin, based on a 1:1 eutectic mixture of lidocaine and prilocaine emulsified in water, were investigated with a poly(dimethylsiloxane) membrane partition model. Aqueous solutions and solubilized systems of lidocaine and prilocaine in a 1:1 ratio by weight were also included in the study as well as the eutectic mixture itself. Two identical sets of samples were used, one of which was gelled with carbomer 934 P. Drug solubilities in the membrane, partition coefficients between membrane and water, and diffusion coefficients in the membrane and the formulations were determined. As in the case of an aqueous medium, lidocaine and prilocaine in combination had lower solubilities in the membrane than they did separately. However, in the aqueous phase or in the membrane, the diffusion coefficients were mutually independent. Carbomer 934P, when neutralized totally with sodium hydroxide, did not decrease the aqueous diffusivities of the local anesthetic bases. The major advantages of using the emulsion formulation based on a eutectic mixture rather than more conventional formulations are: (a) the local anesthetic bases are present in their permeable uncharged forms; (b) the use of a poor solvent, water, as the vehicle provides a saturated system at low concentrations; (c) lipophilic solvent is absent in the dispersed phase, the presence of which would decrease the effective distribution coefficients of the active substances between the skin and the formulation; (d) the droplets consist of dissolvable drug and act as reservoirs to obtain steady-state release; and (e) the fluid state of the excess drug provides a higher dissolution rate than from a solid state.

Phase distribution studies on an oil-water emulsion based on a eutectic mixture of lidocaine and prilocaine as the dispersed phase

The distribution conditions in oil-water emulsions prepared by emulsifying a 1:1 eutectic mixture of lidocaine and prilocaine with a nonionic surfactant in water were studied by membrane and gel filtration methods. In this system, the local anesthetics are considered to be freely dissolved, surfactant solubilized, and emulsified in three separate phases. The dispersity of the oil phase was investigated by light microscopy and light-scatter spectroscopy. The majority of drops in the lidocaine-prilocaine emulsions were less than 1 micron in size. The concentration of freely dissolved drug in the aqueous phase of the emulsions was equal to the aqueous solubility of lidocaine-prilocaine in a 1:1 ratio. At constant lidocaine/prilocaine/surfactant ratio, increasing the total drug concentration in the emulsion resulted in an increase of the emulsified fraction of lidocaine-prilocaine, whereas the surfactant-solubilized fraction remained constant.

Dissolution dialysis studies of metronidazole-montmorillonite adsorbates

In the context of the potential usefulness of clays in retarding the rate of release of adsorbed drugs, dissolution dialysis studies of the release of metronidazole from montmorillonite adsorbates have been conducted. The goal was to develop a means for improving local gastrointestinal therapy of amebiasis while concurrently maintaining efficacy in treating hepatic amebiasis. At acidic pH, the clay was in a flocculated state and the rate of drug release was inhibited. This effect was apparently due to slow diffusion of the drug throughout the clay flocculate. A physical admixture of montmorillonite and metronidazole was also effective in inhibiting the rate of release of metronidazole. Upon increasing the pH to 7, the clay particles progressively deflocculated and the rate of release increased significantly.

Investigation of the beta-cyclodextrin-hydrocortisone inclusion compound

The formation of an inclusion compound by beta-cyclodextrin with hydrocortisone has been studied by proton magnetic resonance (1H-NMR) and phase solubility analysis. The magnitude of the chemical shifts of the interior and exterior beta-cyclodextrin protons in the presence of hydrocortisone indicated that hydrocortisone is included within the beta-cyclodextrin cavity and probably interacts with protons on the edge of the torus. The overall stoichiometry of the inclusion compound was not a single, simple relationship, but was unusual in that it was variable and apparently dependent on the relative amounts of hydrocortisone and beta-cyclodextrin in the system.

Particulate matter in four reconstituted cephalosporin injections

The amount and size of particulate contamination in three commercially available cephalosporin injections and a new product, anophilized cephalothin sodium injection, were studied. Particles in reconstituted cephalothin sodium (commercially available and anophilized), cephapirin sodium, and cephradine injections were counted using two methods: (1) modified USP membrane-filtration technique and (2) Elzone computerized particle analyzer. The amount of particulate contamination in the ranges of 10-24 and greater than or equal to 25 microns was determined by both methods. In the 10-24-microns range, the cephalothin, cephapirin, and cephradine products had significantly greater particle counts than the anophilized cephalothin product. The greater than or equal to 25-microns particle counts showed that the cephapirin and cephradine products had particle counts greater than the anophilized cephalothin product, while total particle counts showed the same results as the 10-24-microns particle counts. A comparison of counting methods showed that the only significant difference between the number of particulates obtained using the modified USP and Elzone computer methods was with the cephalothin product. Anophilized cephalothin sodium injection has significantly fewer particles in the size ranges studied. No conclusion could be reached as to the more accurate method for counting particles.

Phase solubility analysis and PMR study of complexing behavior of dinoprostone with beta-cyclodextrin in water

The mechanism of inclusion compound formation by dinoprostone (prostaglandin E2) with beta-cyclodextrin was studied by phase solubility analysis and PMR spectroscopy. As indicated by the linear increase of aqueous solubility of dinoprostone with beta-cyclodextrin concentration, some types of molecular interactions definitely exist between dinoprostone and the complexing ligands. The temperature dependence of a 1:1 complex formation constant yielded the following thermodynamic data at 20 degrees : deltaG degrees = -4.11 kcal/mole, deltaH degrees = 7.20 kcal/mole, and deltaS degrees = 10.5 e.u. Since water was the solvent system, these parameters appear to be largely determined by solvent reorganization through hydrogen bonding rather than solely by the binding of desolvated free dinoprostone and beta-cyclodextrin entities. PMR data indicate that dinoprostone is included within the cavity and also interacts with protons on the exterior of the beta-cyclodextrin molecule. A model consisting of a 1:1 complex, in which a dinoprostone molecule is partially included within the cavity and the remainder of the molecule extends around the edge of the opening of the cavity to the exterior of the beta-cyclodextrin molecule, is proposed as the most probable structure of this inclusion compound.

Tritiated naltrexone binding in plasma from several species and tissue distribution in mice

The binding of 15,16,-3H-naltrexone in human, monkey, dog, guinea pig, rat, and mouse plasma was investigated over a range of concentrations, including predicted therapeutic levels. Studies using equilibrium dialysis at 37 degrees indicate that the extent of binding is independent of naltrexone concentration over the concentration range of 1-500 ng/ml for dog plasma and of 0.1-500 ng/ml for human, monkey, guinea pig, rat, and mouse plasma. The extent of naltrexone binding in plasma is similar in the six species studied, the range being from 20% bound in rat plasma to 26% in plasma from beagle and mongrel dogs. This relatively low extent of naltrexone binding in plasma is consistent with previous findings of a large apparent volume of distribution of this drug in the dog. To investigate further the distribution of tritiated naltrexone, the tissue levels of radioactivity in mice at 1, 5, and 15 min after intravenous administration of 8-3H-naltrexone were determined. Naltrexone was rapidly distributed from plasma to tissues, with less than 4% of the dose being present in plasma at 1 min after injection.

Metabolic reduction of naltrexone. I. Synthesis, separation and characterization of naloxone and naltrexone reduction products and qualitative assay of urine and bile following administration of naltrexone, alpha-naltrexol, or beta-naltrexol

Reduction of naltrexone and naloxone with sodium borohydride gave a mixture (85:15) of the 6alpha- and 6beta-hydroxy epimers, alpha- and beta-naltrexol and alpha- and beta-naloxol, respectively. Each pair of epimers was separated by preparative thin-layer chromatography and the physical and spectral properties of each compound were determined. Previous assignments for the configuration of the epimers were verified. A semi-quantitative electron capture gas-liquid chromatographic method was devised for distinguishing either alpha- or beta-naltrexol in the presence of the other and in the presence of large amounts (at least 10-fold greater) of naltrexone. The method was used to determine the approximate weight ratio of beta-naltrexol to naltrexone present in enzymatically hydrolyzed urine samples. It was found that substantially greater quantities of beta-naltrexol and/or its conjugates were excreted in the urine of man, monkey, guinea pig and rabbit after administration of naltrexone, whereas very small quantities were excreted by the mouse, rat and dog. In contrast, just trace amounts of the 6alpha-hydroxy epimer, alpha-naltrexol, were detected in the urine of only 2 of the 7 species that had received naltrexone, i.e., monkey and guinea pig. After administration of 3H-15,16-naltrexone, 1 mg/kg, i.v. to the guinea pig, 25% of the radioactivity found following thin-layer chromatography of the extract of acid-hydrolyzed urine corresponded to beta-naltrexol. In gall bladder bile from the guinea pig, only conjugates of naltrexone and beta-naltrexol were found 2 hours after administration of naltrexone. Following administration of beta-naltrexol, 1 mg/kg, i.v. to guinea pigs only beta-naltrexol and/or its conjugates were detected in urine or bile. However, urine collected after administration of alpha-naltrexol, 1 mg/kg, i.v. to guinea pigs contained alpha-naltrexol and its conjugates, as well as a yet unidentified metabolite.