Comparison of equivalent doses of fentanyl buccal tablets and arteriovenous differences in fentanyl pharmacokinetics

BACKGROUND

The fentanyl buccal tablet (FBT) is designed to enhance the rate and extent of fentanyl absorption through the buccal mucosa.

AIM

To evaluate the bioequivalence of microg-equivalent doses of FBT administered as single and multiple tablets and assess differences in the arterial and venous pharmacokinetics of FBT in healthy volunteers.

METHODS

Twenty-seven healthy adults, aged 19-45 years, participated in the randomised, open-label, three-period, crossover study. In the first two periods, FBT was administered as four 100 microg tablets simultaneously or one FBT 400 microg to assess bioequivalence. Venous blood samples were obtained over a 72-hour period to measure plasma fentanyl concentrations. In the third period, arterial and venous blood samples were obtained simultaneously from before administration of one FBT 400 microg through 4 hours after administration to evaluate the impact of arterial versus venous sampling on the pharmacokinetic profile. As subjects were not opioid tolerant, naltrexone was administered to block opioid receptor-mediated effects of fentanyl. Adverse events were recorded throughout.

RESULTS

Maximum plasma concentration (C(max)) and area under the plasma concentration-time curve from time zero to infinity (AUC(infinity)) on average were approximately 12% and 13% higher, respectively, for FBT administered as four 100 microg tablets simultaneously compared with one FBT 400 microg. Maximum plasma concentrations in the arterial circulation were approximately 60% higher and occurred 15 minutes earlier than those measured from the venous circulation. No serious adverse events were reported during the study.

CONCLUSION

Despite small differences in C(max) and AUC(infinity) (on average 12% and 13%, respectively), FBT administered as four 100 microg tablets simultaneously compared with one 400 microg tablet did not meet the criteria for bioequivalence. An increased surface area exposure with four tablets compared with one tablet may account for the slightly higher maximum concentrations observed with four 100 microg tablets. A substantially higher C(max) was reached earlier in the arterial than in the venous circulation.

Statistical optimisation of the mucoadhesivity and characterisation of multipolymeric propranolol matrices for buccal therapy

A Box-Behnken experimental design was employed to optimise a polymeric blend for the preparation of propranolol HCl matrices with maximum mucoadhesivity and was thereafter modified for achieving controlled drug release. The quantitative effects of the polymers used i.e. poly(acrylic acid) (PAA) and poly(vinyl pyrrolidone) (PVP) on mucoadhesion could be predicted using polynomial equations. A formulation of 20% PAA, 20% CMC and 20% PVP was identified for maximising mucoadhesivity and obtaining a controlled drug release profile. Reproducibility of the optimal formulation in terms of mucoadhesivity and controlled drug release was confirmed. The optimal formulation was characterised in terms of mucoadhesivity, release kinetics, swelling/erosion, hydration dynamics and surface pH. From the model fitting analyses, drug release was found to be diffusion, polymeric relaxation and erosion based with the former two being more dominant over erosion. This was in agreement with the erosion and swelling studies which showed swelling and erosion occurring in the tablet matrix. Textural profiling showed initial rapid hydration, which could be beneficial for enhanced mucoadhesivity. Surface pH of the multipolymeric matrices was similar to salivary pH and did not show extremes in changes over the test period. The optimal preparation of multipolymeric propranolol matrices identified in this study shows potential for buccal administration.

Misoprostol Administered by Epithelial Routes

OBJECTIVE

To quantify and compare serum levels and uterine effects following vaginal (dry), vaginal (moistened), buccal, and rectal misoprostol administration.

METHODS

Forty women seeking elective abortion between 6 and 12 6/7 weeks were randomly assigned to receive 400 mug of misoprostol by one of four routes. A 2.5-mm pressure monitoring catheter was placed through the cervix to the uterine fundus to record uterine tone and activity during the 5-hour observation period. Serum levels of misoprostol acid were measured at 15 and 30 minutes, then every 30 minutes.

RESULTS

The four groups were similar in age, race or ethnicity, body mass index, parity, and gestation. Serum levels after vaginal, vaginal moistened and buccal administration rose gradually, peaked between 15 and 120 minutes and fell slowly. Vaginal and vaginal moistened routes produced higher peak serum levels than buccal and rectal (445.9 and 427.1 compared with 264.8 and 202.2 pg/mL; P = .03) and higher serum concentration area under the curve at 5 hours (1,025.0 and 1279.4 compared with 519.6 and 312.5 pg-hr/mL; P < .001). Uterine tone and activity, however, were similar for buccal and the two vaginal routes. After rectal administration, serum levels peaked earlier (P < .001) then dropped more abruptly, and peak uterine tone (P < .001) and total activity (P = .04) were lower than after the other routes.

CONCLUSION

Although serum levels were lower for buccal compared with the vaginal routes, the three routes produced similar uterine tone and activity. Rectal administration produced lower uterine tone and activity. Vaginal serum levels were two to three and a half times higher than those observed in prior misoprostol pharmacokinetic studies.

5-methyl-pyrrolidinone chitosan films as carriers for buccal administration of proteins

The purpose of this research was to investigate 5-methyl-pyrrolidinone chitosan (MPC) films as carriers for buccal delivery of protein drugs. Placebo and protein-loaded MPC films were prepared by casting and were then cross-linked with tripolyphosphate at different pH conditions. Myoglobin (MHb) was chosen as the model protein because its molecular weight is under the permeability limit of the buccal mucosa. The observed characteristics like bioadhesiveness, swelling behavior, and in vitro release of MHb from loaded films furnish information on the functional behavior of these films. The results obtained show that the modulation of MHb release was achieved only through chitosan cross-linking; the best results in release rate control were obtained by cross-linking performed at pH 6.5. Good bioadhesion properties were maintained even with high cross-linking degrees; the swelling index of MHb-loaded films at different cross-linking degrees evaluated at pH 7.4 and pH 6.4 were comparable to those of placebo films. By setting suitable tripolyphosphate cross-linking conditions for MPC films, one can control protein release without affecting bioadhesion.

Introduction of the dilation and evacuation procedure for second-trimester abortion in Vietnam using manual vacuum aspiration and buccal misoprostol

BACKGROUND

The dilation and evacuation (D&E) procedure was modified for use in a low-resource setting where access to electric vacuum aspiration is limited.

METHOD

In this demonstration project, buccal misoprostol is used for cervical preparation, followed by evacuation using manual vacuum aspiration (MVA) and forceps. Senior physicians at the Hanoi Obstetrics and Gynecology Hospital were trained in D&E and subsequently conducted 439 D&E procedures.

RESULTS

The primary outcomes were efficacy and safety. Secondary outcome measures include efficacy of buccal misoprostol for cervical preparation prior to D&E and the feasibility of MVA for use in the D&E procedure.

CONCLUSION

Successful abortion took place in 100% of the cases. Three major complications occurred. This procedure may be appropriate in other low-resource settings lacking safe, effective abortion services in the second trimester.

Cancer-related breakthrough pain

Breakthrough pain is a common problem in patients with cancer, and is associated with significant morbidity among this group of patients. This review examines the different types of breakthrough pain, and the various options for the management of breakthrough pain.

Diffusion of naltrexone across reconstituted human oral epithelium and histomorphological features

In transbuccal absorption a major limitation could be the low permeability of the mucosa which implies low drug bioavailability. The ability of naltrexone hydrochloride (NLX) to penetrate a resembling histologically human buccal mucosa was assessed and the occurrence of any histomorphological changes observed. We used reconstituted human oral (RHO) non-keratinised epithelium as mucosal section and a Transwell diffusion cells system as bicompartmental model. Buccal permeation was expressed in terms of drug flux (J(s)) and permeability coefficients (K(p)). Data were collected using both artificial and natural human saliva. The main finding was that RHO does not restrain NLX permeation. Drug transport across the epithelium was observed also in presence of various concentrations of penetration enhancers, without any significant differences. On the contrary, the flux throughout the mucosa was extensively affected by iontophoresis. Histologically, no sign of flogosis was observed in any specimen under experiment without iontophoresis, whereas cytoarchitectural changes, up to nuclear pycnosis or cellular swelling, were determined as a consequence of the application of electric fields.

Buccal bioadhesive drug delivery--a promising option for orally less efficient drugs

Rapid developments in the field of molecular biology and gene technology resulted in generation of many macromolecular drugs including peptides, proteins, polysaccharides and nucleic acids in great number possessing superior pharmacological efficacy with site specificity and devoid of untoward and toxic effects. However, the main impediment for the oral delivery of these drugs as potential therapeutic agents is their extensive presystemic metabolism, instability in acidic environment resulting into inadequate and erratic oral absorption. Parenteral route of administration is the only established route that overcomes all these drawbacks associated with these orally less/inefficient drugs. But, these formulations are costly, have least patient compliance, require repeated administration, in addition to the other hazardous effects associated with this route. Over the last few decades' pharmaceutical scientists throughout the world are trying to explore transdermal and transmucosal routes as an alternative to injections. Among the various transmucosal sites available, mucosa of the buccal cavity was found to be the most convenient and easily accessible site for the delivery of therapeutic agents for both local and systemic delivery as retentive dosage forms, because it has expanse of smooth muscle which is relatively immobile, abundant vascularization, rapid recovery time after exposure to stress and the near absence of langerhans cells. Direct access to the systemic circulation through the internal jugular vein bypasses drugs from the hepatic first pass metabolism leading to high bioavailability. Further, these dosage forms are self-administrable, cheap and have superior patient compliance. Developing a dosage form with the optimum pharmacokinetics is a promising area for continued research as it is enormously important and intellectually challenging. With the right dosage form design, local environment of the mucosa can be controlled and manipulated in order to optimize the rate of drug dissolution and permeation. A rational approach to dosage form design requires a complete understanding of the physicochemical and biopharmaceutical properties of the drug and excipients. Advances in experimental and computational methodologies will be helpful in shortening the processing time from formulation design to clinical use. This paper aims to review the developments in the buccal adhesive drug delivery systems to provide basic principles to the young scientists, which will be useful to circumvent the difficulties associated with the formulation design.

Physicochemical Characterization and Evaluation of Buccal Adhesive Patches Containing Propranolol Hydrochloride

Buccal adhesive patches containing 20 mg of propranolol hydrochloride were prepared using solvent casting method. Chitosan was used as a natural bioadhesive polymer. Patches were prepared at different ratios of PVP K-30 and evaluated for various physicochemical characteristics such as weight variation, drug content uniformity, folding endurance, surface pH, ex-vivo mucoadhesive strength, ex-vivo residence time, in vitro drug release and in vitro buccal permeation study. Patches exhibited sustained release over a period of 7 hours. The mechanism of drug release was found to be Non-Fickian diffusion. Addition of PVP K-30 generally enhanced the releasing rate. The ex-vivo mucoadhesive strength was performed using sheep buccal mucosa on modified physical balance. Optimized patches (batch F4) showed satisfactory bioadhesive strength (9.6 degrees 2.0 gram) and ex vivo residence time (272 degrees 0.25 minutes). Swelling index was proportional to PVP K-30. The surface pH of all batches was within satisfactory limit (7.0+/-1.5) and hence patches would not cause irritation in the buccal cavity. Good correlation was observed between in vitro drug release and in vitro drug permeation with correlation coefficient of 0.9364. Stability of optimized patches was performed in natural human saliva showed that both drug and dosage forms were stable in human saliva.

Evaluation of hybrid liposomes-encapsulated silymarin regarding physical stability and in vivo performance

Silymarin, a known standardized extract obtained from seeds of Silybum marianum is used in treatment of liver diseases of varying origins. Aiming at improving its poor bioavailability from oral products, silymarin hybrid liposomes are introduced in this work for buccal administration after investigating their stability and in vivo hepatoprotective efficiency. Silymarin loaded hybrid liposomes composed of lecithin (L), cholesterol (Ch), stearyl amine (SA) and Tween 20 (T20) in molar ratio of (9:1:1:0.5) were prepared. Their stability upon storage was studied at 4 degrees C and at ambient conditions. Stored samples were analyzed for percent encapsulation, drug release, particle size, turbidity measurement and visual changes. Characterization of the blend between phospholipid and silymarin was done using FT-IR and DSC which indicated a possible interaction. The stabilized formula of silymarin hybrid liposomes was evaluated upon buccal administration regarding its hepatoprotective activity against carbon tetrachloride-induced oxidative stress in albino rats. The degree of protection was measured using biochemical parameters like serum glutamic oxalacetate transaminase (SGOT) and serum glutamic pyruvate transaminase (SGPT). The introduced silymarin hybrid liposomes produced a significant decrease in both transaminase levels when challenged with CCl(4) (intraperitonially) in comparison with orally administered silymarin suspension. This improvement was also confirmed histopathologically.

Testosterone Hormone Replacement Therapy: State-of-the-Art and Emerging Technologies

In the human male, testosterone is the major circulating androgen. The clinical effects of androgen are numerous, and testosterone deficiency is associated with a number of clinical abnormalities. At present, a variety of preparations containing testosterone is available for the treatment of androgen deficiency. Ideally, those treatments have to produce and maintain physiologic serum concentrations of the hormone. This article reviews the current existing testosterone dosage forms on the market with their advantages and drawbacks and examines new and emerging technology developments concerning this therapy. In particular, the latest innovations in transdermal delivery are explored.

Pharmacokinetic properties of fentanyl effervescent buccal tablets: A phase I, open-label, crossover study of single-dose 100, 200, 400, and 800 μg in healthy adult volunteers

BACKGROUND

The fentanyl effervescent buccal tablet (FEBT) is designed to enhance the rate and extent of the absorption of fentanyl, an opioid, through the buccal mucosa.

OBJECTIVES

The purposes of this study were to assess the dose proportionality of FEBT in healthy volunteers over the potential therapeutic dose range (100-800 microg) and characterize the pharmacokinetic (PK) profile of 4 doses (100, 200, 400, and 800 microg) of FEBT.

METHODS

This Phase I, randomized, open-label, 4-period crossover study was conducted at Radiant Research, Honolulu, Hawaii. Healthy adult volunteers with intolerance to opioids were randomly assigned to receive 1 of 4 single-dose sequences of FEBT: 100, 200, 400, and 800 microg (selected to encompass the anticipated therapeutic dose range), with each successive administration separated by a washout period of >or=7 days. Naltrexone hydrochloride (50-mg tablet) was administered-15 and 3 hours before and 9 hours after FEBT administration to block opioid receptor-mediated effects of fentanyl. Plasma fentanyl concentrations were measured from venous samples obtained over 72 hours after FEBT administration. Early fentanyl exposure was assessed using AUC from time 0 to 0.75 hour (the median T(max) of the reference dose [100 microg]) (AUC(0-Tmax')). Adverse events (AEs) were monitored and recorded throughout the study by medically qualified personnel.

RESULTS

Thirty-two subjects (26 men, 6 women; mean [SD] age, 29.3 [7.2] years [range, 19-44 years]; mean [SD] weight, 74.7 [10.7] kg) were enrolled. Median T was between 35 and 45 minutes after FEBT administration. AUC(0-infinity) and C(max) increased approximately linearly with increasing doses of FEBT. Mean plasma fentanyl concentrations decreased from C(max) in a biexponential manner at the 100- and 200-microg doses and decreased in a triexponential manner at the 800-mug dose. Despite the triexponential decrease in the mean profile observed with the 400-microg dose, a biexponential decrease was observed in approximately half of the individual profiles. AUC(0-Tmax') ranged from 0.09 ng x h/mL with the 100-microg dose to 0.52 ng x h/mL with the 800-microg dose. The most commonly reported AEs in the 100-, 200-, 400-, and 800-microg dose groups were as follows: application-site erythema, 3, 3, 4, and 3 subjects, respectively; nausea, 3, 2, 5, and 4 subjects; somnolence, 3, 2, 3, and 2 subjects; and headache, 3, 2, 1, and 4 subjects. None of the AEs were serious.

CONCLUSIONS

In this study of the dose proportionality of FEBT in healthy volunteers, the PK profile of FEBT was characterized by a high early systemic exposure of fentanyl (0.09-0.52 ng x h/mL). Dose-dependent parameters (C(max) and AUC) increased in an approximately dose-proportional manner from 100 to 800 microg FEBT.

Relative bioavailability of the fentanyl effervescent buccal tablet (FEBT) 1080 pg versus Oral transmucosal fentanyl citrate 1600 pg and dose proportionality of FEBT 270 to 1300 μg: A single-dose, randomized, open-label, three-period study in healthy adult volunteers

BACKGROUND

The fentanyl effervescent buccal tablet (FEBT) was designed to enhance the rate and extent of absorption of fentanyl through the buccal mucosa. FEBT is being investigated for the management of breakthrough pain.

OBJECTIVES

The primary objective of this study was to compare the relative bioavailability of FEBT 1,080 microg with that of oral transmucosal fentanyl citrate (OTFC) 1,600 microg, and the secondary objective was to assess the dose proportionality of FEBT 270 to 1,300 microg in healthy adult volunteers.

METHODS

This single-dose, randomized, open-label, 3-period study was conducted by MDS Pharma Services, Lincoln, Nebraska. Non-opioid-tolerant healthy adult volunteers were included. In periods 1 and 2 (relative-bioavailability analysis), subjects were randomly assigned to 1 of 2 administration sequences: single-dose FEBT 1,080 microg followed by single-dose OTFC 1,600 microg, or vice versa; in period 3 (dose-proportionality analysis), they were randomly assigned to receive a single dose of FEBT 270, 810, or 1,300 microg. Subjects were instructed to place FEBT between the gum and cheek above an upper molar tooth and allow it to disintegrate for 10 minutes. Subjects were instructed to place the OTFC lozenge between the cheek and lower gum and move the unit from side to side using the handle and allow the unit to dissolve for 15 minutes. All subjects received naltrexone 50 mg PO at 15 and 3 hours before and 12 hours after fentanyl administration, except those receiving FEBT 270 microg, who were not given naltrexone at 12 hours. For the measurement of serum concentrations of fentanyl, venous blood samples were collected before and up to 36 hours after study drug administration. For tolerability analysis, continuous pulse oximetry, 12-lead electrocardiography, clinical laboratory analysis, and physical examination, including vital-sign measurements, were performed; the oral mucosa was inspected; and spontaneous reporting was employed.

RESULTS

A total of 42 subjects were enrolled (25 women, 17 men; mean [SD] age, 27 [11] years; mean [SD] weight, 68.4 [8.7] kg); 39 completed the study. Total systemic exposure (as measured using AUC(0-infinity))) was statistically similar between FEBT 1,080 microg and OTFC 1,600 microg (mean [SD], 18.0 [5.4] vs 18.0 [7.1] ng x h/mL). However, the mean (SD) C(max) with FEBT 1,080 microg was 2.7 (0.9) ng/mL compared with 2.2 (0.7) ng/mL with OTFC 1,600 microg (P = NS), and the T(max) of 1.0 hour with FEBT was significantly less compared with OTFC (2.0 hours; P < 0.001). Similarly, mean (SD) early systemic exposure (AUC(0-Tmax'); ie, AUC from time 0 to 1 hour the median T(max) of the reference dose of FEBT [810 microg]) was significantly greater with FEBT compared with OTFC (1.5 [0.5] vs 0.8 [0.4] ng x h/mL; P < 0.001). Exploratory analyses suggested dose proportionality as assessed using AUC(0-infinity) and AUC(0-Tmax') over the range of FEBT 270 to 1,300 microg. Increases in C(max) were less than dose proportional at FEBT doses >810 microg. Definitive attribution of adverse events (AEs) to FEBT or OTFC was generally not possible because these medications were coadministered with naltrexone. With naltrexone alone, there were reports of headache (3 [7%] subjects), nausea (1 [2%]), upset stomach (1 [2%]), and low systolic blood pressure (1 [2%]) after naltrexone administration, but before FEBT or OTFC administration. The AEs were typical of opioids (ie, headache, nausea, lightheadedness), and most (89.6%) were mild. One case each of mild oral irritation and redness were reported after the administration of FEBT Both occurrences resolved within 4.5 hours after study drug administration. No irritation or redness was reported after the administration of OTFC.

CONCLUSIONS

In this pharmacokinetic study in healthy volunteers, total systemic exposure increased in a dose-proportional manner up to FEBT 1,300 microg, whereas doses above 810 microg showed a less-than-dose-proportional increase in C(max). The results suggest that fentanyl enters the systemic circulation to a significantly greater extent (C(max) and AUC(0-Tmax')) and significantly more rapidly (T(max)) with FEBT compared with OTFC.

Cyclodextrin-containing poly(ethyleneoxide) tablets for the delivery of poorly soluble drugs: potential as buccal delivery system

The aim of this work was to develop a tablet for the buccal delivery of the poorly soluble drug carvedilol (CAR), based on poly(ethyleneoxide) (PEO) as bioadhesive sustained-release platform and hydroxypropyl-beta-cyclodextrin (HPbetaCD) as modulator of drug release. As first, PEO tablets loaded with CAR/HPbetaCD binary systems with different dissolution properties were tested for CAR and HPbetaCD release features and compared to PEO tablets containing only CAR. When the drug was incorporated as CAR/HPbetaCD freeze-dried product, all CAR content was released from the tablet in about 10 h, displaying a constant release regimen after a transient. The effect of HPbetaCD incorporation on the release mechanism, was rationalized on the basis of the interplay of different physical phenomena: erosion and swelling of the tablet, drug dissolution, drug counter-diffusion and complex formation. In the second part of the study, the potential of HPbetaCD-containing PEO tablets as buccal delivery system for CAR was tested. It was found that the incorporation of HPbetaCD in the tablet did not alter significantly its good adhesion properties. The feasibility of buccal administration of CAR was assessed by permeation experiments on pig excised mucosa. The amount of CAR permeated from PEO tablet was higher in the case of HPbetaCD-containing tablets, the maximum value being obtained for CAR/HPbetaCD freeze-dried system. Our results demonstrate that, when the tablet is employed as transmucosal system, the role of drug dissolution enhancement in the hydrated tablet is much more relevant than in solution for increasing the delivery rate.

Articaine and Lidocaine Mandibular Buccal Infiltration Anesthesia: A Prospective Randomized Double-Blind Cross-Over Study

This randomized crossover double-blind trial compared the efficacy of buccal infiltration with 4% articaine and 2% lidocaine (both with 1:100,000 epinephrine) in securing mandibular first molar pulp anesthesia. Injections were given at least 1 week apart in 31 healthy adult volunteers. Electronic pulp testing was undertaken at baseline and at 2 minute intervals until 30 minutes postinjection. A successful outcome was recorded in the absence of pulp sensation on two consecutive maximal pulp tester stimulations (80 muA). 64.5% of articaine and 38.7% of lidocaine infiltrations were successful (p = 0.008). Articaine infiltration produced significantly more episodes of no response to maximum stimulation in first molars than lidocaine (236 and 129, respectively, p < 0.001). Mandibular buccal infiltration is more effective with 4% articaine with epinephrine compared to 2% lidocaine with epinephrine. Both injections were associated with mild discomfort.

Is permanent maxillary tooth removal without palatal injection possible?

OBJECTIVE

The aim of the present study was to demonstrate if articaine HCl could provide palatal anesthesia in maxillary tooth removal without the need for a second palatal injection.

STUDY DESIGN

Of 53 patients, 23 had bilateral and 30 had unilateral extractions. In the study group 2 mL of 4% articaine/HCl with 1:100,000 epinephrine was injected into the buccal vestibule of the tooth. After 5 min the extraction was performed. 27 subjects were controls and subjected to the same protocol with palatal injection. All patients completed a Faces Pain Scale (FPS) and a 100-mm Visual Analogue Scale (VAS) after extraction.

RESULTS

According to VAS and FPS scores, when permanent maxillary tooth removal with palatal injection (97.5%) and without palatal injection (96.8%) were compared the difference was not statistically significant (P > .05) [corrected].

CONCLUSION

Permanent removal of maxillary teeth without palatal injection is possible by depositing 2 mL articaine/HCl to the buccal vestibule of the tooth.

In vivo human buccal permeability of nicotine

The aim was to examine the in vivo buccal pH-dependent permeability of nicotine in humans and furthermore compare the in vivo permeability of nicotine to previous in vitro permeability data. The buccal permeability of nicotine was examined in a three-way cross-over study in eight healthy non-smokers using a buccal perfusion cell. The disappearance of nicotine from perfusion solutions with pH 6.0, 7.4, and 8.1 was studied for 3h. The apparent permeability of nicotine (P(app)) was determined at each pH value. Parotid saliva was collected in an attempt to assess systemic levels of nicotine. The disappearance rate of nicotine increased significantly as the pH increased, which resulted in P(app) values of 0.57+/-0.55 x 10(-4), 2.10+/-0.23 x 10(-4), and 3.96+/-0.54 x 10(-4)cms(-1) (mean+/-S.D.) at pH 6.0, 7.4, and 8.1, respectively. A linear relationship (R(2)=0.993) was obtained between the P(app) values and non-ionised nicotine, which indicates that the nicotine transfer occurred by means of passive diffusion. P(app) values of 0.60 x 10(-4) and 6.18 x 10(-4)cms(-1) were obtained for the mono-protonated and non-ionised species of nicotine, respectively. The analysis of the parotid saliva samples indicated that these samples might be useful in the assessment of systemic absorption of nicotine. Previous buccal in vitro models underestimated the in vivo human permeability of nicotine. However, the in vitro models were capable of predicting the effect of pH on the nicotine permeability.

Buccal vs. nasogastric tube administration of tacrolimus after pediatric liver transplantation

Tacrolimus is an important drug for immunosuppression after liver transplantation. Bioavailability of enterally administered tacrolimus is poor, and further reduced by gastric residuals or by enteral nutrition. Buccal administration might be an alternative route especially in children. Tacrolimus trough levels (TTLs) obtained after buccal administration of tacrolimus after liver transplantation have not been reported. The aim of this study was to determine whether buccal administration of tacrolimus is feasible and to compare TTLs after nasogastric tube (NGT) administration with buccal administration. TTLs after NGT or buccal administration during the first week after pediatric liver transplantation were analyzed from 28 cadaveric liver transplants in 23 pediatric recipients between June 2002 and March 2004. Each level was scored within, under or above the target range. Buccal administration was well tolerated in all patients. A total of 149 TTLs were obtained of which nine were excluded because of incomplete information on target levels. Overall 27% of TTLs was adequate. The percentage of levels under, within and above the target range were comparable in both groups (chi-square test; p = 0.64). Both groups had a decrease in percentages within the target range on day 3 and 4 after liver transplantation with a subsequent rise. Buccal tacrolimus administration is feasible. Similar TTLs are achieved compared with NGT tacrolimus administration during the first week after pediatric liver transplantation.

Cervical preparation using laminaria with adjunctive buccal misoprostol before second-trimester dilation and evacuation procedures: a randomized clinical trial

OBJECTIVE

This study was undertaken to determine whether buccal misoprostol improves cervical preparation achieved with laminaria before second-trimester dilation and evacuation procedures.

STUDY DESIGN

A randomized, double blind, placebo-controlled trial of preoperative cervical preparation with overnight laminaria and either buccal placebo or 400 microg buccal misoprostol approximately 90 minutes before second-trimester surgical abortion. Block randomization was used to provide balanced enrollment into 2 separate gestational age study groups: early (13-15(6/7)) and mid (16-20(6/7)) second trimester. Surgeons tested maximal cervical dilation by inserting the largest dilator that could be passed through the cervical os without force. Subject demographics and preprocedure symptoms were tracked.

RESULTS

Groups were similar in regard to age, gravity, parity, delivery type, and gestational age. Data were analyzed from 125 women in the 13 to 15(6/7) (30 misoprostol, 32 placebo) and 16 to 20(6/7) (31 misoprostol, 32 placebo) gestational age groups. Overall, misoprostol treatment did not improve the initial mean dilation achieved with laminaria alone in either the 13 to 15(6/7) (46.0 fr +/- 5.0; placebo 45.0 fr +/- 6.2, P = .68) or 16 to 20(6/7) (50.9 fr +/- 5.6, placebo 48.9 fr +/- 5.2, P = .16) groups. However, a subanalysis of gestations 19 weeks or more demonstrated significantly greater dilation in the misoprostol group (53.6 fr fr +/- 5.3, placebo 48.5 fr +/- 5.0, P = .01). Subjects receiving misoprostol reported significantly more cramping than those receiving placebo (13-15(6/7) weeks misoprostol 25/30, 83%; placebo 17/32, 53%, P = .02; 16-20(6/7) week misoprostol 25/31, 81%, placebo 16/32, 50%, P = .02).

CONCLUSION

Cervical dilation with laminaria is augmented by 400 microg buccal misoprostol in gestations 19 weeks or more, but not in earlier gestations. Misoprostol causes more abdominal cramping.

New absorption promoter for the buccal delivery: Preparation and characterization of lysalbinic acid

Drug delivery across the buccal mucosa is convenient and safe transport method. The efficiency of the buccal system of peptide delivery is, however, not yet satisfactory. To improve the buccal transport new absorption promoters should be developed to be sufficiently active and at the same time causing no side effects like irritation or unpleasant taste. We have found that lysalbinic acid, a product of the alkaline hydrolysis of egg albumin and a mild detergent, meets those requirements. The preparation and some physicochemical properties of lysalbinic acid are described. Hamster cheek pouch was used as a model for the penetration process studies lysalbinic acid was shown to increase significantly an oral mucosa permeability for alpha-interferon and insulin. So this substance of the natural origin can be applied as an absorption enhancer for the buccal delivery of peptide drugs.

Increased remineralization of tooth enamel by milk containing added casein phosphopeptide-amorphous calcium phosphate

Casein phosphopeptide amorphous calcium phosphate nanocomplexes (CPP-ACP) in chewing gum, lozenges and mouthrinses have been shown to remineralize enamel subsurface lesions in human in situ experiments. The aim of this double-blind, randomized clinical study was to investigate the capacity of CPP-ACP added to bovine milk to remineralize enamel subsurface lesions in situ. Ten subjects drank milk containing either 2·0 or 5·0 g CPP-ACP/l or a control milk whilst wearing removable appliances with enamel slabs containing subsurface demineralized lesions. Each 200 ml milk sample was consumed once a day for each weekday over three consecutive weeks. After each treatment and one weeks rest the subjects crossed over to the other treatments. At the completion of the treatments the enamel slabs were removed and remineralization determined using microradiography and microdensitometry. The results demonstrated that all three milk samples remineralized enamel subsurface lesions. However, the milk samples containing CPP-ACP produced significantly greater remineralization than the control milk. The remineralising effect of CPP-ACP in milk was dose-dependent with 2·0 and 5·0 g CPP-ACP/l producing an increase in mineral content of 70 and 148%, respectively, relative to the control milk. The differences in remineralization following exposure to the three milk samples were all statistically significant (P<0·001). In conclusion, this study shows that the addition of 2·0–5·0 g CPP-ACP/l to milk substantially increases its ability to remineralize enamel subsurface lesions.

Thiolated Chitosans: Design and In Vivo Evaluation of a Mucoadhesive Buccal Peptide Drug Delivery System

PURPOSE

Intravenous application of pituitary adenylate cyclase-activating polypeptide (PACAP) has been identified as a promising strategy for the treatment of type 2 diabetes. To generate a more applicable formulation, it was the aim of this study to develop a sustained buccal delivery system for this promising therapeutic peptide.

METHODS

2-Iminothiolane was covalently bound to chitosan to improve the mucoadhesive and permeation-enhancing properties of chitosan used as drug carrier matrix. The resulting chitosan-4-thiobutylamidine conjugate was homogenized with the enzyme inhibitor and permeation mediator glutathione (gamma-Glu-Cys-Gly), Brij 35, and PACAP (formulation A). The mixture was lyophilized and compressed into flat-faced discs (18 mm in diameter). One formulation was additionally coated on one side with palm wax (formulation B). Tablets consisting of unmodified chitosan and PACAP (formulation C) or of unmodified chitosan, Brij 35, and PACAP (formulation D) served as controls. Bioavailability studies were performed in pigs by buccal administration of these test formulations. Blood samples were analyzed via an ELISA method.

RESULTS

Formulations A and B led to an absolute bioavailability of 1%, whereas PACAP did not reach the systemic circulation when administered via formulations C and D. Moreover, in the case of formulations A and B, a continuously raised plasma level of the peptide drug being in the therapeutic range could be maintained over the whole period of application (6 h). Formulations A and B were removed by moderate force from the buccal mucosa after 6 h, whereas formulations C and D detached from the mucosa 4 h after application.

CONCLUSION

The study reveals this novel mucoadhesive delivery system to be a promising approach for buccal delivery of PACAP.

Fentanyl Buccal Tablet

The fentanyl buccal tablet (FBT) is a new formulation of fentanyl that uses an effervescent drug delivery system to enhance penetration across the buccal mucosa for the treatment of breakthrough pain in opioid-tolerant patients with cancer. Fentanyl is rapidly absorbed from FBT across the buccal mucosa and into the bloodstream. Fentanyl is more rapidly absorbed and bioavailability is higher from FBT than from the oral transmucosal fentanyl citrate formulation. In a well designed phase III trial in opioid-tolerant patients with cancer, a single dose of FBT 100-800 microg provided clinically significant improvements in pain intensity from 15 to 60 minutes after the dose. Single FBT doses of 100-800 microg were generally well tolerated; the majority of adverse events were mild to moderate in nature and typical of those associated with opioids.

Comparison of Oxycodone Pharmacokinetics after Buccal and Sublingual Administration in Children

OBJECTIVE

We evaluated and compared the pharmacokinetics of two oral administration routes of oxycodone parenteral liquid (10 mg/mL)--single buccal and sublingual administration--in 30 generally healthy awake children, aged 6-91 months.

METHODS

Two groups of children undergoing inpatient surgery were enrolled. In a randomised fashion, children received a single dose of oxycodone 0.2 mg/kg buccally (n = 15) or sublingually (n = 15). Regular blood samples were collected for up to 12 hours, and plasma was analysed for oxycodone, oxymorphone and noroxycodone using gas chromatography-mass spectrometry.

RESULTS

Bioavailability was similar after administration at the two instillation sites. The area under the plasma concentration-time curve from time zero extrapolated to infinity (AUCinfinity) was 2400-8000 ng x min/mL (median 4200 ng x min/mL) in the buccal group and 2700-7900 ng x min/mL (median 5500 ng x min/mL) in the sublingual group. After buccal administration, maximum plasma concentration (Cmax) was 5.4-39 ng/mL (16 ng/mL) after buccal and 5.5-42 ng/mL (22 ng/mL) after sublingual administration. Twelve of the 15 children in both groups reached the oxycodone analgesic concentration of 12 ng/mL, which was sustained for 43-209 minutes (median 160 minutes) in the children with buccal oxycodone and for 32-262 minutes (median 175 minutes) in the children with sublingual oxycodone. The terminal elimination half-lives were closely similar in the two groups: 104-251 minutes (median 140 minutes) in the buccal group and 110-190 minutes (150 minutes) in the sublingual group.

CONCLUSION

The results of this study show that in young children the absorption of oxycodone is similar after buccal and sublingual instillation.