Resting and exertional haemodynamic effects of buccal nitroglycerin: acute and chronic discontinuous treatment in post-myocardial infarction patients with heart failure

The resting and exertional haemodynamic effects of acute and chronic discontinuous (one tablet every 6 h) treatment with 5 mg of buccal nitroglycerin (BN) have been assessed in nine postinfarction heart failure patients. At rest, pulmonary artery (PAP), pulmonary wedge (PWP), and right atrial pressures (RAP) were reduced by 42%, 55% and 77%, respectively, after the first dose and by 26%, 32% and 45%, respectively, after the chronic (three weeks) treatment with BN. During exercise, at the same workload, PAP, PWP and RAP were significantly reduced by 44%, 54% and 62%, respectively, after acute treatment and by 28%, 34% and 44%, respectively, after chronic treatment. The maximal workload (Kgm) increased by 179% and 166% and the exercise time increased by 78% and 71% after acute and chronic therapy, respectively. At the maximal workload, after acute BN, overall haemodynamics were better than in the basal state. PAP, PWP and RAP were still reduced by 19%, 31% and 31%, respectively, after acute treatment, while after chronic phase the results did not differ from control. The severity of cardiac failure, according to the Weber classification, was reduced by acute and chronic therapy. We can conclude that the buccal nitroglycerin showed clear efficacy in improving overall haemodynamic parameters both at rest and during exercise in post-myocardial infarction patients with heart failure. The discontinuous treatment maintained the effect of nitroglycerin without clear evidence of tolerance during chronic therapy.

Regression of experimental oral carcinomas by local injection of beta-carotene and canthaxanthin

Regression of 7,12-dimethylbenz[a]anthracene (DMBA)-induced epidermoid carcinomas of hamster buccal pouch was accomplished by local injections of beta-carotene and canthaxanthin. One-hundred male hamsters (2-3 months old) were divided into five groups of 20 animals. All animals had the right buccal pouches painted three times weekly for 14 weeks with a 0.5% solution of DMBA in mineral oil, at which time all animals exhibited gross tumors of variable size and number. Group 1 animals were then injected locally into the right buccal pouch twice weekly for 4 weeks with 250 micrograms-carotene in 0.1 ml minimal essential medium (MEM) per injection. Group 2 animals were similarly injected with 250 micrograms canthaxanthin in 0.1 ml MEM. Group 3 animals were similarly injected with 250 micrograms 13-cis-retinoic acid in 0.1 ml MEM. Group 4 animals were injected only with MEM; Group 5 animals were untreated controls. Animals were killed in a carbon dioxide chamber, and buccal pouches were photographed. Tumors were counted and measured. Tumor burden in each group was compared, and statistical significance between groups was recorded. beta-Carotene was more effective than canthaxanthin in tumor regression. 13-cis-Retinoic acid had no effect in this system.

Serum morphine concentrations after buccal and intramuscular morphine administration

1. This study compared serum concentrations of morphine after administration of a buccal tablet (25mg) with those after intramuscular injection (10mg). 2. Buccal morphine was administered to eleven healthy volunteers and intramuscular morphine was given to five preoperative surgical patients. Serum morphine concentrations were assayed by high performance liquid chromatography (h.p.l.c.) in samples taken up to 8 h after drug administration. 3. Mean maximum morphine concentrations were eight times lower after buccal administration than after intramuscular injection and occurred at a mean of 4 h later. Individual morphine concentration-time profiles showed marked interindividual variability after administration of the buccal tablet, consistent with considerable variation in tablet persistence time on the buccal mucosa.

Meperidine pharmacokinetics following intravenous, peroral and buccal administration in beagle dogs

The pharmacokinetics of meperidine was studied in Beagle dogs following intravenous, peroral and buccal administration of a meperidine hydrochloride solution. The elimination half-life after I.V., P.O. and buccal routes was 0.75 +/- 0.14 hours, 0.93 +/- 0.18 hours and 0.36 +/- 0.10 hours, respectively. The volume of distribution and total clearance following I.V., P.O. and buccal administration were 2.41 +/- 0.34 L/kg and 42.5 +/- 8.9 ml/min/kg, 2.84 +/- 1.24 L/kg and 34.6 +/- 7.8 ml/min/kg, 1.01 +/- 0.52 L/kg and 34.7 +/- 8.0 ml/min/kg, respectively. The absolute bioavailability after P.O. and buccal administration was 11.0 +/- 6.8% and 11.9 +/- 6.6%, respectively. This paper discusses the observed low bioavailabilities on hypothesis of hepatic and lung first-pass effect. A hypothesis is presented to explain the delayed onset of absorption following buccal administration.

Influence of pH on the buccal absorption of morphine sulphate and its major metabolite, morphine-3-glucuronide

Buccal absorption of morphine sulphate and morphine-3-glucuronide at various buffer pH values (4 to 10) over 5 min has been investigated in seven and four normal healthy volunteers, respectively. Increasing pH caused an increase in buccal absorption of both. The maximum mean absorption was 37% at pH 10 for morphine and 19% at pH 8 for morphine-3-glucuronide.

Moment analysis of intravenous, intraduodenal, buccal, rectal and percutaneous nifedipine in rats

The pharmacokinetics and bioavailability of intravenous, intraduodenal, buccal, rectal and percutaneous nifedipine were studied in rats to evaluate the influence of route of administration. Plasma concentrations of nifedipine were determined by electron capture gas-liquid chromatography with preliminary oxidation of the drug to its pyridine analog. Pharmacokinetic evaluations were carried out by noncompartmental analysis of plasma concentration-time curves based on the statistical moment theory. The moments were computed by fitting a polyexponential function to the discrete time-course data of plasma concentration using the iterative least-squares method. A good computer fit to biexponential kinetics and a short mean residence time were observed after intravenous administration (i.v.). The linear distribution and disposition of nifedipine was found within the dosing range tested (0.025-0.100 mg/kg, i.v.). The systemic availability of nifedipine after intraduodenal administration was on the average between 52% and 57%, indicating that nifedipine is extensively metabolized during first passage through the liver. Avoidance of first-pass metabolism was investigated following buccal, rectal and percutaneous administration to rats. These nonportal routes of administration gave approximately 10-30% increases in systemic availability compared to that from intraduodenal nifedipine delivery. Moment analysis revealed variations of mixing condition of nifedipine at the dosing site. It was shown that the absorption occurs in a mammillary manner after intraduodenal and rectal administration. On the other hand, there is steady-state absorption of the drug from the buccal route of administration. Following percutaneous administration, the drug seems to be absorbed catenary to some degree.(ABSTRACT TRUNCATED AT 250 WORDS)

Buccal versus sublingual nitroglycerin administration in the treatment of angina pectoris: a multicentre study

Buccal (Suscard) was compared with sublingual nitroglycerin (Nitromex) in 126 patients with stable angina pectoris. Following a dose adjustment period they were randomized to cross-over treatment, two weeks on sublingual and buccal nitroglycerin, respectively. The dosage of buccal nitroglycerin was 2.5 mg in 49% and 5.0 mg in 51%. The total number of treated acute anginal attacks was 31% less during the buccal compared to the sublingual nitroglycerin period (P less than 0.001) despite a reported physical activity level which was significantly higher during the buccal nitroglycerin period. The use of sublingual nitroglycerin and buccal nitroglycerin was considered equally simple by 67%, sublingual nitroglycerin easier by 19% and buccal nitroglycerin easier by 14% of the patients. Sublingual nitroglycerin was used prophylactically on 806 occasions and buccal nitroglycerin on 929 occasions (P less than 0.05) with success in 66% of the sublingual nitroglycerin-attempts and 74% of the buccal nitroglycerin-attempts (P less than 0.05). Considering only prophylactic use, buccal nitroglycerin was preferred by 81% and sublingual nitroglycerin by 4% (P less than 0.05). When given the opportunity only to select one of the two nitroglycerin formulations, 65% (P less than 0.05) preferred buccal nitroglycerin and 19% sublingual nitroglycerin. In conclusion, buccal nitroglycerin seems to be more efficacious than sublingual nitroglycerin. The explanation is probably that the two formulations are comparable in the treatment of acute anginal attacks, while buccal nitroglycerin has a more pronounced prophylactic effect due to its longer duration of action.

Studies on drug absorption from oral cavity. II. Influence of the unstirred water layer on absorption from hamster cheek pouch in vitro and in vivo

The influence of the unstirred water layer (UWL) adjacent to the membrane surface of the hamster cheek pouch on absorption was studied in vitro and in vivo. The tissue uptake rate of 14C-laurylalcohol was determined in vitro and the value of the effective resistance of UWL (RW) was calculated. RW values were reduced by increasing the stirring rate of the mucosal solution. In vitro permeation of 14C-benzoic acid into the serosal compartment was also increased in the well-stirred condition. Thus, the existence of UWL as an effective diffusion barrier for drug absorption from the hamster cheek pouch was suggested. To clarify the influence of the existence of UWL on the absorption in vivo, the apparatus for luminal stirring was newly devised. When the luminal solution was well-stirred, the absorption of benzoic acid in the lower pH region significantly increased, resulting in the disappearance of the shift of pH-absorption curve for benzoic acid. Furthermore, the luminal stirring increased the absorption rate constant for salicylic acid. From these experimental results, it is suggested that UWL plays a part of barriers against drug permeation in the hamster cheek pouch.